# Efficacy and Safety of Wuling Powder in the Treatment of Patients with Diabetic Nephropathy: A Systematic Review and Meta-Analysis

Authors: Yunyi Yang; Wenjun Sha; Keke Hou; Yuanying Xu; Shufa Tan; Hongping Yin; Lin Chen; Tao Lei
Journal: Evidence-Based Complementary and Alternative Medicine
 (2022)

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## Abstract

Background. Wuling powder is a classical formula of traditional Chinese medicine (TCM), which is extensively applied to treat diabetic nephropathy (DN). However, there are no related reports on systematically evaluating the efficacy of Wuling powder in the treatment of DN. Targeted at this, this study was developed. Materials and Methods. This study systematically searched related articles from nine databases, including PubMed, Cochrane Library, Embase, Web of Science, China Knowledge Infrastructure (CNKI), China Biomedical CD-ROM (Sino Med), Wanfang database, Vipers database (VIP), and the China Clinical Trials Registry website. The randomized controlled trials (RCTs) involving Wuling Power to treat DN were included, which were published from the established data of the above databases to March 2022. In addition, the language of the studies was not restricted. Studies were meta-analyzed using the RevMan 5.4 software given in the Cochrane Collaboration Network. The treatment efficacy was measured using the weighted mean differences (WMD) and 95% confidence intervals (CI). Results. 24 studies were included for the final analysis. 24 h urine volume (WMD = 357.95; 95% CI [322.83, 393.06], p<0.00001), 24 h urine protein quantification(24 h UPQ) (WMD = −1.30; 95% CI [−1.82, −0.78], p<0.00001), serum creatinine (Scr) (WMD = −10.17; 95% CI [−11.13, −9.21], p<0.00001), blood urea nitrogen (BUN) (WMD = −1.62; 95% CI [−2.30, −0.93], p<0.00001), urinary albumin excretion rate (UAER) (WMD = −24.73; 95% CI [−35.46, −13.99], p<0.00001), fasting blood glucose (FBG) (WMD = −0.63.95% CI [−0.97, −0.30], p = 0.002), glycated hemoglobin (WMD = −0.11; 95% CI [−0.30, 0.08], p=0.26), total cholesterol (TC) (WMD = −0.63; 95% CI [−1.23, −0.04], p=0.04), triglycerides (TG) (WMD = −0.46. 95% CI [−0.70, −0.23], p=0.0001), high-density lipoprotein cholesterol (HDL-C) (WMD = −0.32; 95% CI [0.03, 0.62], p=0.03), low-density lipoprotein cholesterol (LDL-C) (WMD = −0.57; 95% CI [−0.77, −0.37], p<0.00001), and total effective rate (TER) (response ratio (RR) = 1.40; 95% CI [1.32, 1.48]; p<0.00001) were concluded. The Wuling powder in the treatment of DN was statistically significant in all the above outcome indicators, and the efficacy of the treatment group was better than that of the control group. Conclusion. The results of this study provided evidence for the clinical application of Wuling powder to treat the DN, but it had to be further validated in higher-quality clinical studies.


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## Body

## 1. Introduction

Diabetic nephropathy (DN) is the most common and serious microvascular complication of diabetes mellitus (DM). It is clinically characterized by persistent albuminuria and/or progressive decline in glomerular filtration rate and microangiopathy, and it may result in end-stage renal disease in severe cases. Therefore, it becomes one of the leading causes of death in patients with DM [1]. The number of patients with DM in China ranks first all over the world, and its incidence is increasing year by year [2, 3]. In recent years, studies have shown that the incidence of nephropathy caused by DM has increased rapidly, surpassing glomerulonephritis and hypertension [4]. Once the DN has progressed to renal failure, it will be difficult to reverse, which seriously affects the life, health, and quality of life of patients, and brings serious mental and economic burdens to their families. Currently, angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers can reduce the urinary protein, which can slow down the progression of DN, but its effect is not ideal [5]. Therefore, it is urgent to develop new treatment methods for DN.The history of treating DN using Traditional Chinese medicine (TCM) is long, so the experience is highly enriched. In addition, the people-oriented and evidence-based TCM has achieved good clinical efficacy in the treatment of DN, and so it has become popular [6]. In TCM, DM is included in “oedema” and “thirst,” and its pathogenesis is determined as water metabolism disorders, Qi deficiency, blood stasis, paralysis, and obstruction of veins and ligaments, resulting in dysfunction of internal organs. As a classical TCM formula, Wuling powder was first recorded in the Treatise on Miscellaneous Diseases of Typhoid Fever, written by Zhang Zhong Jing, a famous doctor in the Eastern Han Dynasty. It can play the effect of dipping water and dampness, warming Yang, and transforming Qi. Wuling powder has been approved by the State Food and Drug Administration in China (approval number: Z11020702). The drug compositions of Wuling powder were as follows: Polyporus umbellatus (Pers.) Fries (zhū líng), Poria cocos (Schw.) Wolf (fú líng), Atractylodes macrocephala Koidz (bái zhú), Alisma plantago-aquatica L. var. orientalis (Sam.) Juzep (zé xiè), and Cinnamomum cassia Presl (guì zhī). The compositions and detailed summary of Wuling powder are given in Figure 1 and Table 1, respectively.Figure 1
Compositions of Wuling powder.Table 1
Details of the compositions of Wuling powder.
Chinese herbsLatin nameFamilyPart of herbsFunctions in TCMZhu ling (zhū líng)Polyporus umbellatus (Pers.) FriesSargassaceaeSclerotiumTo clear dampness and promote diuresisFu ling (fú líng)Poria cocos (Schw.) Wolf.PolyporaceaeSclerotiumTo clear dampness, promote diuresis, strengthen the spleen, and calm the heartBai Zhu (bái zhú)Atractylodes macrocephala Koidz.AsteraceaeRoots and rhizomesTo invigorate Qi and spleen, dry damp, stop sweating, and relieve miscarriageZe Xie (zé xiè)Alisma plantago-aquatica L.var. orientali s(Sam.) Juzep.AlismataceaeRoots and rhizomesTo dry damp, release heat, resolve turbidity, and lower lipidsGui Zhi(guì zhī)Cinnamomum cassia Presl.LauraceaeTwigTo sweat and relieve the surface, dispel cold and relieve pain, and clear the Yang and transform QiIn this formula, Poria cocos Wolf, Polyporus umbellatus, and Alisma plantago-aquatica exerted the effect of diuresis and dampness percolation; Atractylodes macrocephala Koidz strengthened the spleen and transported damp, and it strengthened the spleen and dispelled damp together with Poria cocos Wolf; Cinnamomum cassia warmed Yang to help the bladder to transform Qi, so that water could flow on its own, which could not only lightly percolate the water and damp but also strengthen the spleen for water and damp transportation. Modern pharmacological studies have shown that Wuling powder has a protective effect on patients with DN, greatly improving the renal indicators such as creatinine clearance, urinary protein, and urea nitrogen level [7, 8]. Clinical studies have shown that Wuling powder combined with some specific western medicines can lower the urinary protein, promote the conversion of proteinuria and haematuria to negative, disperse the swelling, decrease the 24 h urinary protein volume, increase the average daily urine volume, regulate the immune inflammatory response, and better the lipid metabolism disorders and hypercoagulability in DN patients, with significant overall efficacy [9–11]. In this meta-analysis, an evidence-based approach was adopted to systematically evaluate the efficacy and safety of Wuling powder to treat DN, aiming to provide a more effective and reliable scientific basis for the clinical treatment of DN.


## 2. Methods

### 2.1. Design

The protocol for this systematic study was registered on the Open Science Framework (INPLASY) platform (https://inplasy.com/) (registration number: INPLASY202240071). It was implemented and executed according to the preferred reporting guidelines for systematic review and meta-analysis protocols [12]. The final report would be in line with the PRISMA recommendations for systematic view reporting of the medical interventions in meta-analysis [13].


### 2.2. Database and Literature Search

This study systematically searched nine databases from their establishment data to March 2022, including PubMed, Cochrane Library, Embase, Web of Science, China Knowledge Infrastructure (CNKI), China Biomedical CD-ROM (Sino Med), Wanfang database, Vipers database (VIP), and China Clinical Trials Registry website. In addition, the patent databases were searched to exclude the clinical trials that were not published due to patent applications for Wuling powder (approval number: Z11020702). The clinical randomized controlled trials (RCTs) focusing on Wuling powder to treat DN were included in this study. The main objective of the first search was to collect the literature comprehensively by taking “Wuling Powder,” “Wuling San,” “Wuling,” “Diabetic Nephropathies,” “Nephropathies, Diabetic,” “Nephropathy, Diabetic,” “Diabetic Nephropathy,” “Diabetic Kidney Disease,” “Diabetic Kidney Diseases,” “Kidney Disease, Diabetic,” “Kidney Diseases, Diabetic” “Diabetic Glomerulosclerosis,” “Glomerulosclerosis, Diabetic,” “Intracapillary Glomerulosclerosis, Diabetic.” “Intracapillary Glomerulosclerosis,” “Nodular Glomerulosclerosis,” “Glomerulosclerosis, Nodular,” “Kimmelstiel-Wilson Syndrome,” “Kimmelstiel Wilson Syndrome,” “Syndrome, Kimmelstiel-Wilson,” “Kimmelstiel-Wilson Disease,” “Kimmelstiel Wilson Disease,” “Kimmelstiel Wilson Syndrome,” “Kimmelstiel Wilson Disease,” “Kimmelstiel Wilson Disease,” “Kimmelstiel Wilson Disease,” and “Kimmelstiel Wilson Disease” as the search terms. The search strategy was shown in Supplementary Material Table1.


### 2.3. Inclusion and Exclusion Criteria

#### 2.3.1. Types of Research

The selected RCTs were on the Wuling powder plus or minus formula for the treatment of DN.


#### 2.3.2. Subjects of the Studies

In the included studies, the subjects were patients who met the internationally recognized diagnostic criteria for DN at the time of the study, who had been definitively diagnosed with DN by a clinician, and who had excluded primary nephropathy and other causes of renal disease.


#### 2.3.3. Interventions

All patients in the treatment group were treated with Wuling powder plus or minus formula, while those in the control group received other hypoglycaemic drugs; or patients in both treatment and control groups received the same conventional diabetes medication and based on which patients in the treatment group took Wuling powder plus or minus formula. Studies with multiple interventions or where Wuling powder was not the primary intervention were excluded. There were no requirements for the course of the disease, course of treatment, and dose of medication.


#### 2.3.4. Outcome Indicators

The main outcome indicators in this study included 24 h urine volume; 24 h urinary protein quantification (24 h UPQ); serum creatinine (Scr); blood urea nitrogen (BUN); urinary albumin excretion rate (UAER); and total effective rate (TER). The secondary outcome indicators were fasting blood glucose (FBG); hemoglobin A1c; total cholesterol (TC); triglyceride (TG); high-density lipoprotein cholesterol (HDL-C); and low-density lipoprotein cholesterol (LDL-C). In addition, safety was measured based on adverse effects.


#### 2.3.5. Exclusion Criteria

The studies satisfying the below conditions had to be excluded: (1) duplicate publications; (2) reviews, summaries of expert experience, evaluative articles, or theoretical elaborations; (3) not RTCs, or animal studies; (4) nonclinical studies such as pharmacology; and (5) with incomplete documentation of data.


### 2.4. Data Collection and Analysis

#### 2.4.1. Literature Screening

The RCTs were screened independently by two researchers to exclude those who failed to meet the inclusion criteria. After the elimination of the duplicates, the abstracts of the searched RCTs were read for initial screening to exclude the RCTs not meeting the inclusion criteria and all the RCTs were downloaded. Next, the full texts of these RCTs were read. Finally, the RCTs on Wuling powder for DN treatment that met the inclusion criteria were selected. Any different opinions between the two researchers were referred to a third party for adjudication.


#### 2.4.2. Research Data Extraction

The authors, year of publication, mean age, number of trials and controls, course of the disease, number of cases by gender, interventions, duration of treatment, and outcome indicators of the included RCTs were selected. Then, the authors were contacted if the required data were incomplete. Two researchers cross-checked the information entered in the RCTs, and any disagreements were referred to a third party for adjudication.


#### 2.4.3. Assessment on Risk of Bias

The risk of bias of the included RCTs was assessed by using the Risk of Bias Assessment Tool recommended by the Cochrane Collaboration, in terms of seven aspects: (1) random sequence generation method; (2) allocation protocol concealment; (3) blindness to subjects and intervention providers; (4) blindness to outcome assessors; (5) completeness of outcome data; (6) selective reporting of study results; and (7) other biases. For each of the included RCTs, “high risk,” “low risk,” and “unclear risk” were assessed for each aspect [14]. In case of any disagreement on assessment results of the risk of bias, it should be discussed with a third researcher.


#### 2.4.4. Data Analysis

The RevMan 5.4 software provided by the Cochrane Collaboration Network was adopted for meta-analysis. Dichotomous variables were expressed with the response ratio (RR), and the continuous variables were expressed using mean differences (MD). Theχ2 test was performed for heterogeneity. If p>0.1 and I2 < 50%, the heterogeneity among all RCTs was low and the fixed effect model (FEM) was used for meta-analysis; while if p<0.1 and I2 ≥ 50%, the heterogeneity was statistically significant and the random effect model (REM) was used for the meta-analysis. p<0.05 indicated a statistically significant difference.


#### 2.4.5. Heterogeneity Assessment and Sensitivity Analysis

IfI2 ≥ 50%, there was a statistical heterogeneity and the REM was adopted to analyse the data; while the FEM was adopted if the test for heterogeneity was not significant (I2 < 50%). As there was a variation in heterogeneity, the sensitivity analysis or subgroup analysis was essential to explore the potential causes of heterogeneity and to exclude the RCTs with a high risk of bias, so as to ensure the robustness of results.


#### 2.4.6. Subgroup Analysis

Due to differences in heterogeneity, subgroup analysis was required to analyze the possible reasons for heterogeneity. The main subgroup analysis items included different ages, control treatments, duration of treatment, region, and safety.


#### 2.4.7. Assessment of Publication Bias

Publication bias was detected using a funnel plot. A significant asymmetry in the funnel plot meant a publication bias.


## 2.1. Design

The protocol for this systematic study was registered on the Open Science Framework (INPLASY) platform (https://inplasy.com/) (registration number: INPLASY202240071). It was implemented and executed according to the preferred reporting guidelines for systematic review and meta-analysis protocols [12]. The final report would be in line with the PRISMA recommendations for systematic view reporting of the medical interventions in meta-analysis [13].


## 2.2. Database and Literature Search

This study systematically searched nine databases from their establishment data to March 2022, including PubMed, Cochrane Library, Embase, Web of Science, China Knowledge Infrastructure (CNKI), China Biomedical CD-ROM (Sino Med), Wanfang database, Vipers database (VIP), and China Clinical Trials Registry website. In addition, the patent databases were searched to exclude the clinical trials that were not published due to patent applications for Wuling powder (approval number: Z11020702). The clinical randomized controlled trials (RCTs) focusing on Wuling powder to treat DN were included in this study. The main objective of the first search was to collect the literature comprehensively by taking “Wuling Powder,” “Wuling San,” “Wuling,” “Diabetic Nephropathies,” “Nephropathies, Diabetic,” “Nephropathy, Diabetic,” “Diabetic Nephropathy,” “Diabetic Kidney Disease,” “Diabetic Kidney Diseases,” “Kidney Disease, Diabetic,” “Kidney Diseases, Diabetic” “Diabetic Glomerulosclerosis,” “Glomerulosclerosis, Diabetic,” “Intracapillary Glomerulosclerosis, Diabetic.” “Intracapillary Glomerulosclerosis,” “Nodular Glomerulosclerosis,” “Glomerulosclerosis, Nodular,” “Kimmelstiel-Wilson Syndrome,” “Kimmelstiel Wilson Syndrome,” “Syndrome, Kimmelstiel-Wilson,” “Kimmelstiel-Wilson Disease,” “Kimmelstiel Wilson Disease,” “Kimmelstiel Wilson Syndrome,” “Kimmelstiel Wilson Disease,” “Kimmelstiel Wilson Disease,” “Kimmelstiel Wilson Disease,” and “Kimmelstiel Wilson Disease” as the search terms. The search strategy was shown in Supplementary Material Table1.


## 2.3. Inclusion and Exclusion Criteria

### 2.3.1. Types of Research

The selected RCTs were on the Wuling powder plus or minus formula for the treatment of DN.


### 2.3.2. Subjects of the Studies

In the included studies, the subjects were patients who met the internationally recognized diagnostic criteria for DN at the time of the study, who had been definitively diagnosed with DN by a clinician, and who had excluded primary nephropathy and other causes of renal disease.


### 2.3.3. Interventions

All patients in the treatment group were treated with Wuling powder plus or minus formula, while those in the control group received other hypoglycaemic drugs; or patients in both treatment and control groups received the same conventional diabetes medication and based on which patients in the treatment group took Wuling powder plus or minus formula. Studies with multiple interventions or where Wuling powder was not the primary intervention were excluded. There were no requirements for the course of the disease, course of treatment, and dose of medication.


### 2.3.4. Outcome Indicators

The main outcome indicators in this study included 24 h urine volume; 24 h urinary protein quantification (24 h UPQ); serum creatinine (Scr); blood urea nitrogen (BUN); urinary albumin excretion rate (UAER); and total effective rate (TER). The secondary outcome indicators were fasting blood glucose (FBG); hemoglobin A1c; total cholesterol (TC); triglyceride (TG); high-density lipoprotein cholesterol (HDL-C); and low-density lipoprotein cholesterol (LDL-C). In addition, safety was measured based on adverse effects.


### 2.3.5. Exclusion Criteria

The studies satisfying the below conditions had to be excluded: (1) duplicate publications; (2) reviews, summaries of expert experience, evaluative articles, or theoretical elaborations; (3) not RTCs, or animal studies; (4) nonclinical studies such as pharmacology; and (5) with incomplete documentation of data.


## 2.3.1. Types of Research

The selected RCTs were on the Wuling powder plus or minus formula for the treatment of DN.


## 2.3.2. Subjects of the Studies

In the included studies, the subjects were patients who met the internationally recognized diagnostic criteria for DN at the time of the study, who had been definitively diagnosed with DN by a clinician, and who had excluded primary nephropathy and other causes of renal disease.


## 2.3.3. Interventions

All patients in the treatment group were treated with Wuling powder plus or minus formula, while those in the control group received other hypoglycaemic drugs; or patients in both treatment and control groups received the same conventional diabetes medication and based on which patients in the treatment group took Wuling powder plus or minus formula. Studies with multiple interventions or where Wuling powder was not the primary intervention were excluded. There were no requirements for the course of the disease, course of treatment, and dose of medication.


## 2.3.4. Outcome Indicators

The main outcome indicators in this study included 24 h urine volume; 24 h urinary protein quantification (24 h UPQ); serum creatinine (Scr); blood urea nitrogen (BUN); urinary albumin excretion rate (UAER); and total effective rate (TER). The secondary outcome indicators were fasting blood glucose (FBG); hemoglobin A1c; total cholesterol (TC); triglyceride (TG); high-density lipoprotein cholesterol (HDL-C); and low-density lipoprotein cholesterol (LDL-C). In addition, safety was measured based on adverse effects.


## 2.3.5. Exclusion Criteria

The studies satisfying the below conditions had to be excluded: (1) duplicate publications; (2) reviews, summaries of expert experience, evaluative articles, or theoretical elaborations; (3) not RTCs, or animal studies; (4) nonclinical studies such as pharmacology; and (5) with incomplete documentation of data.


## 2.4. Data Collection and Analysis

### 2.4.1. Literature Screening

The RCTs were screened independently by two researchers to exclude those who failed to meet the inclusion criteria. After the elimination of the duplicates, the abstracts of the searched RCTs were read for initial screening to exclude the RCTs not meeting the inclusion criteria and all the RCTs were downloaded. Next, the full texts of these RCTs were read. Finally, the RCTs on Wuling powder for DN treatment that met the inclusion criteria were selected. Any different opinions between the two researchers were referred to a third party for adjudication.


### 2.4.2. Research Data Extraction

The authors, year of publication, mean age, number of trials and controls, course of the disease, number of cases by gender, interventions, duration of treatment, and outcome indicators of the included RCTs were selected. Then, the authors were contacted if the required data were incomplete. Two researchers cross-checked the information entered in the RCTs, and any disagreements were referred to a third party for adjudication.


### 2.4.3. Assessment on Risk of Bias

The risk of bias of the included RCTs was assessed by using the Risk of Bias Assessment Tool recommended by the Cochrane Collaboration, in terms of seven aspects: (1) random sequence generation method; (2) allocation protocol concealment; (3) blindness to subjects and intervention providers; (4) blindness to outcome assessors; (5) completeness of outcome data; (6) selective reporting of study results; and (7) other biases. For each of the included RCTs, “high risk,” “low risk,” and “unclear risk” were assessed for each aspect [14]. In case of any disagreement on assessment results of the risk of bias, it should be discussed with a third researcher.


### 2.4.4. Data Analysis

The RevMan 5.4 software provided by the Cochrane Collaboration Network was adopted for meta-analysis. Dichotomous variables were expressed with the response ratio (RR), and the continuous variables were expressed using mean differences (MD). Theχ2 test was performed for heterogeneity. If p>0.1 and I2 < 50%, the heterogeneity among all RCTs was low and the fixed effect model (FEM) was used for meta-analysis; while if p<0.1 and I2 ≥ 50%, the heterogeneity was statistically significant and the random effect model (REM) was used for the meta-analysis. p<0.05 indicated a statistically significant difference.


### 2.4.5. Heterogeneity Assessment and Sensitivity Analysis

IfI2 ≥ 50%, there was a statistical heterogeneity and the REM was adopted to analyse the data; while the FEM was adopted if the test for heterogeneity was not significant (I2 < 50%). As there was a variation in heterogeneity, the sensitivity analysis or subgroup analysis was essential to explore the potential causes of heterogeneity and to exclude the RCTs with a high risk of bias, so as to ensure the robustness of results.


### 2.4.6. Subgroup Analysis

Due to differences in heterogeneity, subgroup analysis was required to analyze the possible reasons for heterogeneity. The main subgroup analysis items included different ages, control treatments, duration of treatment, region, and safety.


### 2.4.7. Assessment of Publication Bias

Publication bias was detected using a funnel plot. A significant asymmetry in the funnel plot meant a publication bias.


## 2.4.1. Literature Screening

The RCTs were screened independently by two researchers to exclude those who failed to meet the inclusion criteria. After the elimination of the duplicates, the abstracts of the searched RCTs were read for initial screening to exclude the RCTs not meeting the inclusion criteria and all the RCTs were downloaded. Next, the full texts of these RCTs were read. Finally, the RCTs on Wuling powder for DN treatment that met the inclusion criteria were selected. Any different opinions between the two researchers were referred to a third party for adjudication.


## 2.4.2. Research Data Extraction

The authors, year of publication, mean age, number of trials and controls, course of the disease, number of cases by gender, interventions, duration of treatment, and outcome indicators of the included RCTs were selected. Then, the authors were contacted if the required data were incomplete. Two researchers cross-checked the information entered in the RCTs, and any disagreements were referred to a third party for adjudication.


## 2.4.3. Assessment on Risk of Bias

The risk of bias of the included RCTs was assessed by using the Risk of Bias Assessment Tool recommended by the Cochrane Collaboration, in terms of seven aspects: (1) random sequence generation method; (2) allocation protocol concealment; (3) blindness to subjects and intervention providers; (4) blindness to outcome assessors; (5) completeness of outcome data; (6) selective reporting of study results; and (7) other biases. For each of the included RCTs, “high risk,” “low risk,” and “unclear risk” were assessed for each aspect [14]. In case of any disagreement on assessment results of the risk of bias, it should be discussed with a third researcher.


## 2.4.4. Data Analysis

The RevMan 5.4 software provided by the Cochrane Collaboration Network was adopted for meta-analysis. Dichotomous variables were expressed with the response ratio (RR), and the continuous variables were expressed using mean differences (MD). Theχ2 test was performed for heterogeneity. If p>0.1 and I2 < 50%, the heterogeneity among all RCTs was low and the fixed effect model (FEM) was used for meta-analysis; while if p<0.1 and I2 ≥ 50%, the heterogeneity was statistically significant and the random effect model (REM) was used for the meta-analysis. p<0.05 indicated a statistically significant difference.


## 2.4.5. Heterogeneity Assessment and Sensitivity Analysis

IfI2 ≥ 50%, there was a statistical heterogeneity and the REM was adopted to analyse the data; while the FEM was adopted if the test for heterogeneity was not significant (I2 < 50%). As there was a variation in heterogeneity, the sensitivity analysis or subgroup analysis was essential to explore the potential causes of heterogeneity and to exclude the RCTs with a high risk of bias, so as to ensure the robustness of results.


## 2.4.6. Subgroup Analysis

Due to differences in heterogeneity, subgroup analysis was required to analyze the possible reasons for heterogeneity. The main subgroup analysis items included different ages, control treatments, duration of treatment, region, and safety.


## 2.4.7. Assessment of Publication Bias

Publication bias was detected using a funnel plot. A significant asymmetry in the funnel plot meant a publication bias.


## 3. Results

### 3.1. Literature Search

Figure2 showed the flowchart to screen the RCTs. 222 relevant publications were searched from various databases, and 100 duplicates were excluded after the initial screening. Next, 88 not satisfying the inclusion criteria were excluded. Then, after the full texts were read carefully, the publications which were not RCTs, not related to the treatment of DN, and lacked details of the results were excluded. Finally, 24 RCTs [15–38] were included in this meta-analysis.Figure 2
Flowchart of specific publications screening.


### 3.2. Characteristics of the Included RCTs

2,018 patients were included in the 24 RCTs, including 1,030 in the treatment group and 988 in the control group. The mean age of the patients ranged from 50.57 ± 15.17 years old to 69.58 ± 1.65 years old. The intervention for patients in all treatment groups was Wuling powder combined with conventional Western medicine. All 24 RCTs were conducted in China and published in 2003∼2021. The shortest and longest durations of treatment were 3 weeks and 12 weeks, respectively. Table2 showed in detail the basic characteristics of the 24 RCTs.Table 2
Basic characteristics of the included RCTs.
Author, yearAge (T/C)Number (T/C)Duration of disease (T/C, year)Gender (M/F)Intervention (T)Intervention (C)CourseOutcomesRegionZhenying Mao 200358.13/56.14 ± 0280 (160/120)2.11/1.98T (76/84)C (69/51)Wuling powder + RTGliquidone12 w②③④⑥⑧⑨⑫Puyang, HenanShiyun Li 200852.35/51.1542 (21/21)0.88/4.3T (13/8)C (12/9)Wuling powder + RTRT3–4 w①②⑧⑨⑫Zhumadian, HenanKaiwang Xiong 201154.548 (24/24)3∼1626/22Wuling powder + RTRT4 w①②③⑧⑨⑫Fenyi, JiangxiMing Li 2011(57.6 ± 7.1)/(55.8 ± 7.2)59 (29/30)(7.9 ± 5.8)/(7.8 ± 6.5)T (15/14)C (16/14)Wuling powder + RTRT12 w③⑤⑥⑦⑧⑨⑩⑪ShanghaiHongqiang Lei 2013(53.4 ± 10.8)/(52.3 ± 10.5)58 (29/29)NRT (17/12)C (16/13)Wuling powder + RTRT12 w②③④Weinan, ShaanxiYuping Liu 2013(45∼82)/(42∼80)60 (30/30)5/5.5T (20/10)C (18/12)Wuling powder + RTGliquidone8 w②⑤⑥⑧⑨⑫Cangwu, GuangxiHuanxu Chen 2014(52.1 ± 6.3)/(51.3 ± 6.5)89 (46/43)(6.1 ± 1.5)/(5.7 ± 1.3)T (27/19)C (25/18)Wuling powder + RTRT2 w③④⑤⑧⑨⑩⑪⑫Zhongshan, GuangdongQinghua Chen 2015(54.9 ± 7.1)/(53.5 ± 6.3)86 (43/43)(11.1 ± 1.0)/(10.4 ± 1.6)T (27/16)C (25/18)Wuling powder + RTRT4 w⑫Yunfu, GuangdongWenchao Shen 2015(53.7 ± 4.2)/(52.8 ± 4.1)64 (32/32)(6.8 ± 1.2)/(6.9 ± 1.3)T (17/15)C (15/17)Wuling powder + RTRT8 w②⑥⑦⑬Pinghu, ZhejiangXiaoxiang Liu 2015(58.2 ± 6.3)/(59.1 ± 5.4)54 (27/27)(9 ± 1.3)/(10 ± 1.6)T (12/15)C (13/14)Wuling powder + RTRT3 w①②③④⑫BeijingChang Liu 2016(60.5 ± 5.5)/(59.3 ± 5.2)60 (30/30)(8.9 ± 1.1)/(9.2 ± 1.1)T (14/16)C (16/14)Wuling powder + RTRT3 w①⑫BeijingLin Bo 2016(54.2 ± 1.9)/(53.6 ± 1.8)100 (50/50)(3.7 ± 1.3)/(3.6 ± 1.2)T (24/26)C (25/25)Wuling powder + RTGliquidone8 w②⑥⑧⑨Dalian, LiaoningShaoping Zhuo 2016(56.9 ± 3.5)/(58.2 ± 3.2)120 (60/60)(5.8 ± 2.3)/(5.4 ± 2.6)64/56Wuling powder + RTRT8 w③④⑤⑦⑫Lianping, GuangdongRenzhi Jing 2017(52.64 ± 8.81)/(51.29 ± 8.26)68 (34/34)(10.79 ± 4.99)/(11.02 ± 4.92)T (20/14)C (18/16)Wuling powder + RTRT11 w③④⑤⑥⑨⑩⑪⑫⑬Chengdu, SichuanXiaobo Hao 2017(54.5 ± 5.5)/(53.5 ± 5.0)98 (49/49)(15.0 ± 4.0)/(14.5 ± 3.6)T (26/23)C (27/22)Wuling powder + RTRT12 w②③⑥⑧⑨⑩⑪⑫Zhoukou, HenanJing Chen 2017(54.92 ± 5.25)/(53.65 ± 5.63)150 (75/75)(5.39 ± 0.58)/(5.52 ± 0.62)T (54/21)C (51/24)Wuling powder + RTGliquidone8 w⑫Hebi, HenanQiyao Xin 2017(50.57 ± 15.17)/(52.57 ± 15.77)60 (30/30)(12.25 ± 3.77)/(13.17 ± 2.12)T (16/14)C (18/12)Wuling powder + RTRT2 w②③④⑥⑫Guangdong, GuangzhouYu Wang 2018(69.21 ± 1.30)/(69.58 ± 1.65)90 (45/45)NRT (28/17)C (29/16)Wuling powder + RTRT3 w①⑫Zunhua, HebeiYuanyuan Lai 2019(64.3 ± 10.5)/(64.5 ± 10.4)72 (36/36)NRT (21/15)C (20/16)Wuling powder + RTRT12 w⑫BeijingYunyun Zuo 202063/62.5084 (42/42)6.50/5.50T (19/17)C (20/18)Wuling powder + RTRT8 w⑥⑦⑫Urumqi, XinjiangYimei Li 2020(35–75)/(35–75)70 (35/35)(5–21)/(5–21)T (26/9)C (20/15)Wuling powder + RTRT8 w②③④⑥⑦⑨⑩Jinan, ShandongYutian Chen 2020(54.16 ± 12.57)/(50.89 ± 12.12)80 (40/40)(6.32 ± 2.754)/(5.24 ± 2.604)T (27/13)C (23/17)Wuling powder + RTRT8 w②③④⑥⑦⑧⑨⑫Guangdong, GuangzhouXiaoting Wen 202055.540 (20/20)3∼1518/22Wuling powder + RTRT4 w①②③⑫Qitaihe, HeilongjiangZhixiang Jiang 2021(59.3 ± 2.8)/(58.6 ± 2.8)86 (43/43)(7.5 ± 1.7)/(7.2 ± 1.6)T (26/17)C (28/15)Wuling powder + RTRT4 w③④⑤⑫Ezhou, HubeiT: treatment group; C: control group; F: female; M: male; NR: not reported; W: week; RT: western conventional treatment; ①24 h urine volume; ②24 h urine protein quantification; ③Serum creatinine; ④blood urea nitrogen; ⑤urinary albumin excretion rate; ⑥fasting blood glucose; ⑦glycated hemoglobin; ⑧total cholesterol; ⑨triglyceride; ⑩high-density lipoprotein cholesterol; ⑪low-density lipoprotein cholesterol; ⑫total effective rate; ⑬adverse reactions.


### 3.3. Risk of Bias in the Included RCTs

This meta-analysis investigated the risk of bias for all RCTs included. All research projects were randomized into a five-linger group and a control group. A comparison of the 24 RCTs revealed inconsistent randomization of treatment; 9 RCTs [21–23, 28, 30, 31, 34, 36, 38] were determined as low risk of bias because they generated random sequences by random number tables and random coin flips, while the remaining RCTs described only “random allocation” and therefore were determined to be an unclear risk of bias. In addition, 3 RCTs [31, 34, 36] reported allocation concealment, so they were classified as low risk of bias. In terms of performance bias, only 1 RCT [31] reported the double-blind trials, so the remaining 23 RCTs were classified as having a high risk of bias. In terms of reporting bias, only 1 RCT [34] had shedding of participant data and was, therefore, determined to have a high risk of bias. All RCTs were balanced at baseline examination and showed no other bias. The full and detailed analysis results on the risk of bias are shown in Figures 3 and 4.Figure 3
Risk of bias.Figure 4
Summary chart of risk of bias.


### 3.4. Results

#### 3.4.1. 24 h Urine Volume

6 RCTs [16, 17, 24, 25, 32, 37] involving 334 DN patients provided data on 24 h urine volume before and after the intervention. A heterogeneity test (P = 0.03 and I2 = 59%) and a sensitivity analysis revealed that the statistical heterogeneity became lower after the study of Wang et al. [32] was removed (χ2 = 5.16, p=0.27, I2 = 23%; Figure 5), so the FEM was used. The results showed that the 24 h urine volume was significantly higher for patients in the treatment group treated with Wuling powder combined with conventional western medicine (WMD = 357.95; 95% CI [322.83, 393.06], p<0.00001; Figure 5). The subgroup analysis suggested that, in the different age subgroups (p=0.01), the group <60 years (χ2 = 3.52, p=0.32, I2 = 15%) was homogeneous with the group ≥60 years (χ2 = 0.56, p=0.45, I2 = 0%), and the difference was statistically significant. The difference between different regional subgroups (p=0.14) was not significant (Table 3, Supplementary Material Figures 1 and 2).Figure 5
Forest plot of 24 h urine volume.Table 3
Subgroup analysis.
Number of comparisonsResultsP value for overall effectI 2P value for subgroup difference24h urine volumeWMD (95% CI)All comparisons6335.13 [295.01, 375.26]<0.0000159%Age0.01<60 y4360.83 [320.76, 400.91]<0.0000115%≥60y2310.13 [309.15, 311.10]<0.000010%Region0.14Beijing2240.47 [109.29, 371.65]0.00030%Other provinces4344.68 [299.76, 389.59]<0.0000173%24h UPQAll comparisons13−1.30 [−1.82, −0.78]<0.0000198%Age0.002<60 y12−1.44 [−2.01, −0.87]<0.0000199%≥60 y1−0.44 [−0.69, −0.19]0.0005NADifferent control treatment<0.0001Gliquidone3−0.45 [−0.54, −0.35]<0.000010%Other treatments10−2.15 [−2.95, −1.35]<0.0000199%Course of treatment0.05<8 w5−2.63 [−4.16, −1.11]0.000799%≥8 w8−1.00 [−1.53, −0.47]0.000298%Region<0.00001Guangdong province2−117.95 [−129.88, −106.02]<0.000010%Other provinces11−0.90 [−1.28, −0.52]<0.0000197%SCrAll comparisons14−10.17 [−11.13, −9.21]<0.00001100%Course of treatment0.11<8 w6−2.44 [−2.99, −1.89]<0.0000199%≥8 w8−11.16 [−21.76, −0.57]0.0498%Region0.007Guangdong province4−19.36 [−27.52, −11.20]<0.0000190%Other provinces10−8.12 [−9.10, −7.13]<0.00001100%BUNAll comparisons10−1.62 [−2.30, −0.93]<0.0000193%Course of treatment0.26<8 w4−2.01 [−2.79, −1.23]<0.0000181%≥8 w6−1.40 [−2.12, −0.67]0.000286%Region0.41Guangdong province4−1.32 [−2.16, −0.48]0.00283%Other provinces6−1.86 [−2.83, −0.89]0.000295%UAERAll comparisons6−24.73 [−35.46, −13.99]<0.0000196%Age0.11<60 y5−22.49 [−34.09, −10.89]0.000197%≥60 y1−38.41 [−53.97, −22.85]<0.00001NACourse of treatment0.93<8 w2−24.55 [−40.91, −8.18]0.00399%≥8 w4−25.73 [−44.46, −7.00]0.00789%Region0.02Guangdong province2−32.79 [−35.33, −30.25]<0.000010%Other provinces4−20.21 [−30.58, −9.84]0.000188%FBGAll comparisons11−0.63 [−0.97, −0.30]0.000274%Age0.49<60 y9−0.69 [−1.13, −0.25]0.00279%≥60 y2−0.52 [−0.76, −0.28]<0.00010%Different control treatment0.45Gliquidone3−0.87 [−1.72, −0.03]0.0470%Other treatments8−0.52 [−0.85, −0.20]0.00268%Course of treatment0.49<8 w1−0.84 [−1.38, −0.30]0.002NA≥8 w10−0.61 [−0.98, −0.25]0.00176%Region0.67Guangdong province2−0.73 [−1.07, −0.39]<0.00010%Other provinces9−0.61 [−1.04, −0.19]0.00578%Safety0.78No adverse effects9−0.62 [−0.96, −0.28]0.000472%Adverse effects2−0.88 [−2.71, 0.95]0.3489%HbA1CAll comparisons6−0.11 [−0.30, 0.08]0.2655%Age0.56<60 y5−0.08 [−0.34, 0.18]0.5764%≥60 y1−0.17 [−0.35, 0.01]0.07NARegion0.01Guangdong province2−0.35 [−0.55, −0.14]0.00080%Other provinces40.02 [−0.19, 0.23]0.8740%TCAll comparisons9−0.63 [−1.23, −0.04]<0.000196%Age0.06<60 y8−0.72 [−1.36, −0.07]0.0397%≥60 y10.06 [−0.42, 0.54]0.81NADifferent control treatment0.22Gliquidone3−0.14 [−1.00, 0.73]0.7592%Other treatments6−0.88 [−1.68, −0.08]0.0397%Course of treatment0.05<8 w3−1.70 [−3.24, −0.16]0.0399%≥8 w6−0.10 [−0.56, 0.35]0.6588%Region0.99Guangdong province2−0.64 [−2.98, 1.69]0.5999%Other provinces7−0.63 [−1.23, −0.02]0.0496%TGAll comparisons11−0.46 [−0.70, −0.23]0.000196%Age0.08<60 y10−0.50 [−0.74, −0.25]<0.000196%≥60 y1−0.05 [−0.49, 0.39]0.82NADifferent control treatment0.11Gliquidone3−0.27 [−0.45, −0.09]0.00356%Other treatments8−0.55 [−0.83, −0.26]0.000295%Course of treatment0.7<8 w3−0.38 [−0.89, 0.13]0.1498%≥8 w8−0.49 [−0.72, −0.25]<0.000186%Region<0.00001Guangdong province2−0.84 [−0.89, −0.79]<0.000010%Other provinces9−0.36 [−0.55, −0.17]0.000287%HDL- CAll comparisons50.32 [0.03, 0.62]0.0397%Course of treatment0.0002<8 w11.06 [0.72, 1.40]<0.00001NA≥8 w40.17 [−0.14, 0.48]0.2797%Region0.0002Guangdong province11.06 [0.72, 1.40]<0.00001NAOther provinces40.17 [−0.14, 0.48]0.2797%LDL-CAll comparisons4−0.72 [−1.10, −0.34]0.000271%Course of treatment0.02<8 w1−1.17 [−1.57, −0.77]<0.00001NA≥8 w3−0.56 [−0.87, −0.24]0.000540%Region0.02Guangdong province1−1.17 [−1.57, −0.77]<0.00001NAOther provinces3−0.56 [−0.87, −0.24]0.000540%Total effective rateAll comparisons191.40 [1.32, 1.48]<0.0000118%Age0.72<60 y141.39 [1.31, 1.48]<0.0000127%≥60 y51.43 [1.26, 1.62]<0.000010%Different control treatment0.45Gliquidone31.35 [1.22, 1.50]<0.0000115%Other treatments161.42 [1.32, 1.51]<0.0000126%Course of treatment0.37<8 w101.44 [1.32, 1.58]<0.0000111%≥8 w91.37 [1.27, 1.47]<0.0000128%Region0.79Guangdong province51.41 [1.27, 1.58]<0.0000154%Other provinces141.39 [1.30, 1.48]<0.000017%


#### 3.4.2. 24 h UPQ

13 RCTs [15–17, 19, 20, 23, 24, 26, 29, 31, 35–37] (including 1,054 patients) reported the data of 24 UPQ. Significant heterogeneity was found in these 13 RCTs (χ2 = 760.27, p<0.00001, I2 = 98%; Figure 6), so the REM was used. The 24 h UPQ for patients treated with Wuling powder combined with conventional western medicine was higher than that in the control group (WMD = -1.30; 95% CI [−1.82, −0.78], p<0.00001; Figure 6). Because of the large heterogeneity, the subgroup analysis was conducted based on the age, control treatment, duration of treatment, and region; and significant differences were found in intervention effects of different ages (p=0.002), control treatments (p<0.0001), and regions (p<0.0001). It was reflected in the glipizide group (control treatment) (χ2 = 0.1, p=0.95, I2 = 0%) and in Guangdong province (region) (χ2 = 0.36, p=0.55, I2 = 0%), while significant heterogeneity was still observed in the rest (Table 3, Supplementary Material Figures 3–6).Figure 6
Forest plot for 24 h UPQ.


#### 3.4.3. Scr

14 RCTs [15, 17–19, 21, 24, 27–29, 31, 35–38] (including 1,210 participants) reported the Scr data. Significant heterogeneity was found (χ2 = 3628.59, p<0.00001, I2 = 100%; Figure 7), so the meta-analysis was conducted by using a REM. The analysis showed a statistically significant difference in Scr between the treatment and control groups (WMD = −10.17; 95% CI [−11.13, −9.21], p<0.00001; Figure 7), indicating that the Scr was significantly better in the treatment group. In addition, the subgroup analysis was conducted in different durations of treatment and regions, and different durations of treatment showed no statistically significant difference (p=0.11) and different regions showed statistically obvious difference (p=0.007), but significant heterogeneity was still observed (Table 3, Supplementary Material Figures 7 and 8).Figure 7
Forest plot of Scr.


#### 3.4.4. BUN

10 RCTs [15, 19, 21, 24, 27, 28, 31, 35, 36, 38] (including 965 patients) reported the BUN data. The tests showed significant heterogeneity (χ2 = 137.59, p<0.00001, I2 = 93%; Figure 8), so the meta-analysis was conducted by using a REM. The analysis showed a statistically significant difference in BUN between the treatment and control groups (WMD = −1.62; 95% CI [−2.30, −0.93], p<0.00001; Figure 8), indicating that the BUN was significantly better in the treatment group. Subgroup analysis in different durations of treatment and regions showed no significant difference in intervention effects between the two groups (p=0.26 and 0.41 respectively), but significant heterogeneity was still observed (Table 3, Supplementary Material Figures 9 and 10).Figure 8
Forest plot of BUN.


#### 3.4.5. UAER

6 RCTs [18, 20, 21, 27, 28, 38] (including 482 patients) reported on UAER. Tests showed significant heterogeneity (χ2 = 128.55, p<0.00001, I2 = 96%; Figure 9), so a REM was used. A statistically significant difference was found in UAER between the treatment and control groups (WMD = −24.73; 95% CI [−35.46, −13.99], p<0.00001; Figure 9), indicating that the UAER was significantly better in the treatment group. A subgroup analysis suggested the intervention effect was not significantly different in age (p=0.11) and duration of treatment (p=0.93) but showed an obvious difference in regions (p=0.02), with no heterogeneity in the Guangdong region (χ2 = 0.24, p=0.62, I2 = 0%) and the rest still observed significant heterogeneity (Table 3, Supplementary Material Figures 11–13).Figure 9
Forest plot of UAER.


#### 3.4.6. FBG

11 RCTs [15, 18, 20, 23, 26, 28, 29, 31, 34–36] (including 1,013 patients) reported the FBG data. Tests showed significant heterogeneity (χ2 = 38.24, p<0.0001, I2 = 74%; Figure 10), so a REM was adopted for meta-analysis. The analysis results revealed a statistically significant difference in FBG between the treatment and control groups (WMD = −0.63; 95% CI [−0.97, −0.30], p=0.002; Figure 10), suggesting that Wuling powder combined with conventional western medicine may significantly reduce the FBG in DN patients. Based on different ages, control treatments, durations of treatment, regions, and safety, the subgroup analysis was conducted, and the results showed no significant differences in intervention effects (p=0.49, 0.45, 0.49, 0.67, and 0.78, respectively); no heterogeneity was found in the ≥60 years group (χ2 = 0.26, p=0.61, I2 = 0%) in the age subgroup and in Guangdong Province (χ2 = 0.26, p=0.61, I2 = 0%) in the region, while significant heterogeneity was still observed in the rest (Table 3, Supplementary Material Figures 14–18).Figure 10
Forest plot of FBG.


#### 3.4.7. Glycated Hemoglobin

6 RCTs [18, 23, 27, 34–36] (including 467 patients) reported the glycated hemoglobin. A REM was adopted because significant heterogeneity was found among them (χ2 = 11.16, p=0.05, I2 = 55%; Figure 11). The glycated hemoglobin between the treatment and control groups was statistically significant (WMD = −0.11; 95% CI [−0.30, 0.08], p=0.26; Figure 11), indicating that it was significantly better in patients treated with the Wuling powder combined with conventional western medicine. Subgroup analysis showed no significant difference in intervention effects in age (p=0.56) and region (p=0.01), with no heterogeneity in Guangdong Province (χ2 = 0.32, p=0.57, I2 = 0%), while significant heterogeneity was still observed in the rest (Table 3, Supplementary Material Figures 19 and 20).Figure 11
Forest plot of glycated hemoglobin.


#### 3.4.8. Blood Lipids

(1) 9 RCTs [15–18, 20, 21, 26, 29, 36] (856 patients) reported the TC and high heterogeneity was found (χ2 = 228.38, p<0.00001, I2 = 96%; Figure 12). The REM analysis results showed the TC was statistically significant (WMD = −0.63; 95% CI [−1.23, −0.04], p=0.04; Figure 12). In the subgroup analysis, the differences in age, control treatment, duration of treatment, and region (p=0.06, 0.22, 0.05, and 0.99, respectively) were not statistically significant (Table 3, Supplementary Material Figures 21–24).Figure 12
Forest plot of TC.(2) 11 RCTs [15–18, 20, 21, 26, 28, 29, 35, 36] (994 patients) reported TG values and the heterogeneity was high (χ2 = 222.98, p<0.00001, I2 = 96%; Figure 13). The REM analysis results showed (WMD = −0.46; 95% CI [−0.70, −0.23], p=0.0001; Figure 13) the differences in TG between the two groups were statistically significant. In the subgroup analysis, the differences were not statistically significant in age, control treatment, and duration of treatment (p=0.08, 0.11, and 0.7, respectively), were statistically significant in regions (p<0.00001), and not heterogeneous in Guangdong Province (p=0.69, I2 = 0%) (Table 3, Supplementary Material Figures 25–28).Figure 13
Forest plot of TG.(3) RCTs [18, 21, 28, 29, 35] (384 patients) recorded HDL values with a test for heterogeneity (χ2 = 137.26, p<0.00001, I2 = 97%; see Figure 14), indicating high heterogeneity, and using a random effects model, the results showed (WMD = −0.32; 95% CI [0.03,0.62], p=0.03; see Figure 14), the difference between the two groups was statistically significant. In the subgroup analysis, the differences were statistically significant across sessions and regions (all p=0.0002) (Table 3, Supplementary Material Figures 29 and 30).Figure 14
Forest plot of HDL.(4) 4 RCTs [18, 21, 28, 29] (314 patients) recorded LDL values, and the heterogeneity among them was proved to be high (χ2 = 10.28, p=0.02, I2 = 71%; Figure 15), which became lower after the study by Chen et al. [21] was removed (χ2 = 3.34, p = 0.19, I2 = 40%; Figure 15), so the difference between the two groups was statistically significant using a FEM (WMD = −0.57; 95% CI [−0.77, −0.37], p<0.00001). In the subgroup analysis, the differences were statistically significant in control treatment and region (all p=0.02) (Table 3, Supplementary Material Figures 31 and 32).Figure 15
Forest plot of LDL.In summary, Wuling powder showed better performance compared with the conventional methods in the treatment of DN in terms of TC, TG, HDL-C, and LDL-C.


#### 3.4.9. TER

The TER was categorized as markedly effective, effective, and ineffective according to the improvement degree in clinical symptoms and related indicators (mainly 24 h urine volume, 24 h UPQ, Scr, BUN, UAER, and FBG). 19 RCTs [15–17, 20–22, 24, 25, 27–34, 36–38] involving 1,657 patients undertook the TER as an outcome indicator. As there was no significant heterogeneity (χ2 = 21.92, p=0.24, I2 = 18%; Figure 16), an FEM was used. The analysis showed that Wuling powder resulted in a significant increase in TER compared to conventional treatment (RR = 1.40; 95% CI [1.32, 1.48]; p<0.00001; Figure 16). Subgroup analysis based on age, control treatment, duration of treatment, and region showed no significant differences (p=0.72, 0.45, 0.37, and 0.79, respectively) (Table 3, Supplementary Material Figures 33–36).Figure 16
Forest plot of TER.


### 3.5. Adverse Effects

Adverse reactions were reported in 2 out of 24 RTCs. The adverse reactions reported in the study by Shen and Shu [23] were nausea, vomiting, abdominal distension, diarrhea, skin rash, and mild hypoglycemia; while those reported by Jing et al. [28] included nausea, vomiting, back pain, skin pruritus, swelling of lower limbs, thirst, and excessive drinking. No adverse reactions were reported in the remaining RCTs.


### 3.6. Publication Bias

Funnel plots were plotted for studies with >10 literature on combined outcome indicators, and 24 h urine volume, 24 h UPQ, Scr, BUN, UAER, FBG, glycated hemoglobin, TC, TG, HDL-C, LDL-C, and TER after treatment showed significant asymmetry in the funnel plots (Figures17–28), indicating publication bias in the included studies.Figure 17
The publication bias funnel chart of 24 h urine volume.Figure 18
The publication bias funnel chart of 24 h UPQ.Figure 19
The publication bias funnel chart of Scr.Figure 20
The publication bias funnel chart of BUN.Figure 21
The publication bias funnel chart of UAER.Figure 22
The publication bias funnel chart of FBG.Figure 23
The publication bias funnel chart of glycated hemoglobin.Figure 24
The publication bias funnel chart of TC.Figure 25
The publication bias funnel chart of TG.Figure 26
The publication bias funnel chart of HDL-C.Figure 27
The publication bias funnel chart of LDL-C.Figure 28
The publication bias funnel chart of TER.


### 3.7. Certainty of Evidence

The GRADEpro was employed to assess the certainty of the evidence in this study. Table4 showed that the results of 24 h urine output, LDL, and TER were moderate-quality evidence, while other outcomes were low-quality evidences. The high heterogeneity of some outcomes, the low methodological quality, and the high risk of bias were reasons for the poor quality of the evidence. Therefore, Wuling powder should be considered cautiously in the clinical use for DN treatment.Table 4
Certainty of evidence: Wuling powder compared to control treatment for DN. CI, confidence interval; MD, mean difference; RR, risk ratio.
Certainty assessment№ of patientsEffectCertaintyImportance№ of studiesStudy designRisk of biasInconsistencyIndirectnessImprecisionOther considerationsWuling powderPlaceboRelative (95% CI)Absolute (95% CI)24 h urine volume5Randomized trialsSeriousNot seriousNot seriousNot seriousNone122122—MD 357.95 higher (322.83 higher to 393.06 higher)⨁⨁⨁◯ ModerateCRITICAL24 h UPQ13Randomized trialsSeriousSeriousNot seriousNot seriousNone547507—MD 1.3 lower (1.82 lower to 0.78 lower)⨁⨁◯◯ LowCRITICALSCr14Randomized trialsSeriousSeriousNot seriousNot seriousNone626584—MD 10.17 lower (11.13 lower to 9.21 lower)⨁⨁◯◯ LowCRITICALBUN10Randomized trialsSeriousSeriousNot seriousNot seriousNone504461—MD 1.62 lower (2.3 lower to 0.93 lower)⨁⨁◯◯ LowCRITICALUAER6Randomized trialsSeriousSeriousNot seriousNot seriousNone242240—MD 24.73 lower (35.46 lower to 13.99 lower)⨁⨁◯◯ LowCRITICALFBG11Randomized trialsSeriousSeriousNot seriousNot seriousNone525488—MD 0.63 lower (0.97 lower to 0.3 lower)⨁⨁◯◯ LowIMPORTANTHbA1C6Randomized trialsSeriousSeriousNot seriousNot seriousNone232235—MD 0.11 lower (0.3 lower to 0.08 higher)⨁⨁◯◯ LowIMPORTANTTC9Randomized trialsSeriousSeriousNot seriousNot seriousNone449407—MD 0.63 lower (1.23 lower to 0.04 lower)⨁⨁◯◯ LowIMPORTANTTG11Randomized trialsSeriousSeriousNot seriousNot seriousNone518476—MD 0.46 lower (0.7 lower to 0.23 lower)⨁⨁◯◯ LowIMPORTANTHDL5Randomized trialsSeriousSeriousNot seriousNot seriousNone193191—MD 0.32 higher (0.03 higher to 0.62 higher)⨁⨁◯◯ LowIMPORTANTLDL3Randomized trialsSeriousNot seriousNot seriousNot seriousNone112113—MD 0.57 lower (0.77 lower to 0.37 lower)⨁⨁⨁◯ ModerateIMPORTANTOverall effective rate19Randomized trialsSeriousNot seriousNot seriousNot seriousNone758/849 (89.3%)515/808 (63.7%)RR 1.40 (1.32 to 1.48)255 more per 1,000 (from 204 more to 306 more)⨁⨁⨁◯ModerateCRITICAL


## 3.1. Literature Search

Figure2 showed the flowchart to screen the RCTs. 222 relevant publications were searched from various databases, and 100 duplicates were excluded after the initial screening. Next, 88 not satisfying the inclusion criteria were excluded. Then, after the full texts were read carefully, the publications which were not RCTs, not related to the treatment of DN, and lacked details of the results were excluded. Finally, 24 RCTs [15–38] were included in this meta-analysis.Figure 2
Flowchart of specific publications screening.


## 3.2. Characteristics of the Included RCTs

2,018 patients were included in the 24 RCTs, including 1,030 in the treatment group and 988 in the control group. The mean age of the patients ranged from 50.57 ± 15.17 years old to 69.58 ± 1.65 years old. The intervention for patients in all treatment groups was Wuling powder combined with conventional Western medicine. All 24 RCTs were conducted in China and published in 2003∼2021. The shortest and longest durations of treatment were 3 weeks and 12 weeks, respectively. Table2 showed in detail the basic characteristics of the 24 RCTs.Table 2
Basic characteristics of the included RCTs.
Author, yearAge (T/C)Number (T/C)Duration of disease (T/C, year)Gender (M/F)Intervention (T)Intervention (C)CourseOutcomesRegionZhenying Mao 200358.13/56.14 ± 0280 (160/120)2.11/1.98T (76/84)C (69/51)Wuling powder + RTGliquidone12 w②③④⑥⑧⑨⑫Puyang, HenanShiyun Li 200852.35/51.1542 (21/21)0.88/4.3T (13/8)C (12/9)Wuling powder + RTRT3–4 w①②⑧⑨⑫Zhumadian, HenanKaiwang Xiong 201154.548 (24/24)3∼1626/22Wuling powder + RTRT4 w①②③⑧⑨⑫Fenyi, JiangxiMing Li 2011(57.6 ± 7.1)/(55.8 ± 7.2)59 (29/30)(7.9 ± 5.8)/(7.8 ± 6.5)T (15/14)C (16/14)Wuling powder + RTRT12 w③⑤⑥⑦⑧⑨⑩⑪ShanghaiHongqiang Lei 2013(53.4 ± 10.8)/(52.3 ± 10.5)58 (29/29)NRT (17/12)C (16/13)Wuling powder + RTRT12 w②③④Weinan, ShaanxiYuping Liu 2013(45∼82)/(42∼80)60 (30/30)5/5.5T (20/10)C (18/12)Wuling powder + RTGliquidone8 w②⑤⑥⑧⑨⑫Cangwu, GuangxiHuanxu Chen 2014(52.1 ± 6.3)/(51.3 ± 6.5)89 (46/43)(6.1 ± 1.5)/(5.7 ± 1.3)T (27/19)C (25/18)Wuling powder + RTRT2 w③④⑤⑧⑨⑩⑪⑫Zhongshan, GuangdongQinghua Chen 2015(54.9 ± 7.1)/(53.5 ± 6.3)86 (43/43)(11.1 ± 1.0)/(10.4 ± 1.6)T (27/16)C (25/18)Wuling powder + RTRT4 w⑫Yunfu, GuangdongWenchao Shen 2015(53.7 ± 4.2)/(52.8 ± 4.1)64 (32/32)(6.8 ± 1.2)/(6.9 ± 1.3)T (17/15)C (15/17)Wuling powder + RTRT8 w②⑥⑦⑬Pinghu, ZhejiangXiaoxiang Liu 2015(58.2 ± 6.3)/(59.1 ± 5.4)54 (27/27)(9 ± 1.3)/(10 ± 1.6)T (12/15)C (13/14)Wuling powder + RTRT3 w①②③④⑫BeijingChang Liu 2016(60.5 ± 5.5)/(59.3 ± 5.2)60 (30/30)(8.9 ± 1.1)/(9.2 ± 1.1)T (14/16)C (16/14)Wuling powder + RTRT3 w①⑫BeijingLin Bo 2016(54.2 ± 1.9)/(53.6 ± 1.8)100 (50/50)(3.7 ± 1.3)/(3.6 ± 1.2)T (24/26)C (25/25)Wuling powder + RTGliquidone8 w②⑥⑧⑨Dalian, LiaoningShaoping Zhuo 2016(56.9 ± 3.5)/(58.2 ± 3.2)120 (60/60)(5.8 ± 2.3)/(5.4 ± 2.6)64/56Wuling powder + RTRT8 w③④⑤⑦⑫Lianping, GuangdongRenzhi Jing 2017(52.64 ± 8.81)/(51.29 ± 8.26)68 (34/34)(10.79 ± 4.99)/(11.02 ± 4.92)T (20/14)C (18/16)Wuling powder + RTRT11 w③④⑤⑥⑨⑩⑪⑫⑬Chengdu, SichuanXiaobo Hao 2017(54.5 ± 5.5)/(53.5 ± 5.0)98 (49/49)(15.0 ± 4.0)/(14.5 ± 3.6)T (26/23)C (27/22)Wuling powder + RTRT12 w②③⑥⑧⑨⑩⑪⑫Zhoukou, HenanJing Chen 2017(54.92 ± 5.25)/(53.65 ± 5.63)150 (75/75)(5.39 ± 0.58)/(5.52 ± 0.62)T (54/21)C (51/24)Wuling powder + RTGliquidone8 w⑫Hebi, HenanQiyao Xin 2017(50.57 ± 15.17)/(52.57 ± 15.77)60 (30/30)(12.25 ± 3.77)/(13.17 ± 2.12)T (16/14)C (18/12)Wuling powder + RTRT2 w②③④⑥⑫Guangdong, GuangzhouYu Wang 2018(69.21 ± 1.30)/(69.58 ± 1.65)90 (45/45)NRT (28/17)C (29/16)Wuling powder + RTRT3 w①⑫Zunhua, HebeiYuanyuan Lai 2019(64.3 ± 10.5)/(64.5 ± 10.4)72 (36/36)NRT (21/15)C (20/16)Wuling powder + RTRT12 w⑫BeijingYunyun Zuo 202063/62.5084 (42/42)6.50/5.50T (19/17)C (20/18)Wuling powder + RTRT8 w⑥⑦⑫Urumqi, XinjiangYimei Li 2020(35–75)/(35–75)70 (35/35)(5–21)/(5–21)T (26/9)C (20/15)Wuling powder + RTRT8 w②③④⑥⑦⑨⑩Jinan, ShandongYutian Chen 2020(54.16 ± 12.57)/(50.89 ± 12.12)80 (40/40)(6.32 ± 2.754)/(5.24 ± 2.604)T (27/13)C (23/17)Wuling powder + RTRT8 w②③④⑥⑦⑧⑨⑫Guangdong, GuangzhouXiaoting Wen 202055.540 (20/20)3∼1518/22Wuling powder + RTRT4 w①②③⑫Qitaihe, HeilongjiangZhixiang Jiang 2021(59.3 ± 2.8)/(58.6 ± 2.8)86 (43/43)(7.5 ± 1.7)/(7.2 ± 1.6)T (26/17)C (28/15)Wuling powder + RTRT4 w③④⑤⑫Ezhou, HubeiT: treatment group; C: control group; F: female; M: male; NR: not reported; W: week; RT: western conventional treatment; ①24 h urine volume; ②24 h urine protein quantification; ③Serum creatinine; ④blood urea nitrogen; ⑤urinary albumin excretion rate; ⑥fasting blood glucose; ⑦glycated hemoglobin; ⑧total cholesterol; ⑨triglyceride; ⑩high-density lipoprotein cholesterol; ⑪low-density lipoprotein cholesterol; ⑫total effective rate; ⑬adverse reactions.


## 3.3. Risk of Bias in the Included RCTs

This meta-analysis investigated the risk of bias for all RCTs included. All research projects were randomized into a five-linger group and a control group. A comparison of the 24 RCTs revealed inconsistent randomization of treatment; 9 RCTs [21–23, 28, 30, 31, 34, 36, 38] were determined as low risk of bias because they generated random sequences by random number tables and random coin flips, while the remaining RCTs described only “random allocation” and therefore were determined to be an unclear risk of bias. In addition, 3 RCTs [31, 34, 36] reported allocation concealment, so they were classified as low risk of bias. In terms of performance bias, only 1 RCT [31] reported the double-blind trials, so the remaining 23 RCTs were classified as having a high risk of bias. In terms of reporting bias, only 1 RCT [34] had shedding of participant data and was, therefore, determined to have a high risk of bias. All RCTs were balanced at baseline examination and showed no other bias. The full and detailed analysis results on the risk of bias are shown in Figures 3 and 4.Figure 3
Risk of bias.Figure 4
Summary chart of risk of bias.


## 3.4. Results

### 3.4.1. 24 h Urine Volume

6 RCTs [16, 17, 24, 25, 32, 37] involving 334 DN patients provided data on 24 h urine volume before and after the intervention. A heterogeneity test (P = 0.03 and I2 = 59%) and a sensitivity analysis revealed that the statistical heterogeneity became lower after the study of Wang et al. [32] was removed (χ2 = 5.16, p=0.27, I2 = 23%; Figure 5), so the FEM was used. The results showed that the 24 h urine volume was significantly higher for patients in the treatment group treated with Wuling powder combined with conventional western medicine (WMD = 357.95; 95% CI [322.83, 393.06], p<0.00001; Figure 5). The subgroup analysis suggested that, in the different age subgroups (p=0.01), the group <60 years (χ2 = 3.52, p=0.32, I2 = 15%) was homogeneous with the group ≥60 years (χ2 = 0.56, p=0.45, I2 = 0%), and the difference was statistically significant. The difference between different regional subgroups (p=0.14) was not significant (Table 3, Supplementary Material Figures 1 and 2).Figure 5
Forest plot of 24 h urine volume.Table 3
Subgroup analysis.
Number of comparisonsResultsP value for overall effectI 2P value for subgroup difference24h urine volumeWMD (95% CI)All comparisons6335.13 [295.01, 375.26]<0.0000159%Age0.01<60 y4360.83 [320.76, 400.91]<0.0000115%≥60y2310.13 [309.15, 311.10]<0.000010%Region0.14Beijing2240.47 [109.29, 371.65]0.00030%Other provinces4344.68 [299.76, 389.59]<0.0000173%24h UPQAll comparisons13−1.30 [−1.82, −0.78]<0.0000198%Age0.002<60 y12−1.44 [−2.01, −0.87]<0.0000199%≥60 y1−0.44 [−0.69, −0.19]0.0005NADifferent control treatment<0.0001Gliquidone3−0.45 [−0.54, −0.35]<0.000010%Other treatments10−2.15 [−2.95, −1.35]<0.0000199%Course of treatment0.05<8 w5−2.63 [−4.16, −1.11]0.000799%≥8 w8−1.00 [−1.53, −0.47]0.000298%Region<0.00001Guangdong province2−117.95 [−129.88, −106.02]<0.000010%Other provinces11−0.90 [−1.28, −0.52]<0.0000197%SCrAll comparisons14−10.17 [−11.13, −9.21]<0.00001100%Course of treatment0.11<8 w6−2.44 [−2.99, −1.89]<0.0000199%≥8 w8−11.16 [−21.76, −0.57]0.0498%Region0.007Guangdong province4−19.36 [−27.52, −11.20]<0.0000190%Other provinces10−8.12 [−9.10, −7.13]<0.00001100%BUNAll comparisons10−1.62 [−2.30, −0.93]<0.0000193%Course of treatment0.26<8 w4−2.01 [−2.79, −1.23]<0.0000181%≥8 w6−1.40 [−2.12, −0.67]0.000286%Region0.41Guangdong province4−1.32 [−2.16, −0.48]0.00283%Other provinces6−1.86 [−2.83, −0.89]0.000295%UAERAll comparisons6−24.73 [−35.46, −13.99]<0.0000196%Age0.11<60 y5−22.49 [−34.09, −10.89]0.000197%≥60 y1−38.41 [−53.97, −22.85]<0.00001NACourse of treatment0.93<8 w2−24.55 [−40.91, −8.18]0.00399%≥8 w4−25.73 [−44.46, −7.00]0.00789%Region0.02Guangdong province2−32.79 [−35.33, −30.25]<0.000010%Other provinces4−20.21 [−30.58, −9.84]0.000188%FBGAll comparisons11−0.63 [−0.97, −0.30]0.000274%Age0.49<60 y9−0.69 [−1.13, −0.25]0.00279%≥60 y2−0.52 [−0.76, −0.28]<0.00010%Different control treatment0.45Gliquidone3−0.87 [−1.72, −0.03]0.0470%Other treatments8−0.52 [−0.85, −0.20]0.00268%Course of treatment0.49<8 w1−0.84 [−1.38, −0.30]0.002NA≥8 w10−0.61 [−0.98, −0.25]0.00176%Region0.67Guangdong province2−0.73 [−1.07, −0.39]<0.00010%Other provinces9−0.61 [−1.04, −0.19]0.00578%Safety0.78No adverse effects9−0.62 [−0.96, −0.28]0.000472%Adverse effects2−0.88 [−2.71, 0.95]0.3489%HbA1CAll comparisons6−0.11 [−0.30, 0.08]0.2655%Age0.56<60 y5−0.08 [−0.34, 0.18]0.5764%≥60 y1−0.17 [−0.35, 0.01]0.07NARegion0.01Guangdong province2−0.35 [−0.55, −0.14]0.00080%Other provinces40.02 [−0.19, 0.23]0.8740%TCAll comparisons9−0.63 [−1.23, −0.04]<0.000196%Age0.06<60 y8−0.72 [−1.36, −0.07]0.0397%≥60 y10.06 [−0.42, 0.54]0.81NADifferent control treatment0.22Gliquidone3−0.14 [−1.00, 0.73]0.7592%Other treatments6−0.88 [−1.68, −0.08]0.0397%Course of treatment0.05<8 w3−1.70 [−3.24, −0.16]0.0399%≥8 w6−0.10 [−0.56, 0.35]0.6588%Region0.99Guangdong province2−0.64 [−2.98, 1.69]0.5999%Other provinces7−0.63 [−1.23, −0.02]0.0496%TGAll comparisons11−0.46 [−0.70, −0.23]0.000196%Age0.08<60 y10−0.50 [−0.74, −0.25]<0.000196%≥60 y1−0.05 [−0.49, 0.39]0.82NADifferent control treatment0.11Gliquidone3−0.27 [−0.45, −0.09]0.00356%Other treatments8−0.55 [−0.83, −0.26]0.000295%Course of treatment0.7<8 w3−0.38 [−0.89, 0.13]0.1498%≥8 w8−0.49 [−0.72, −0.25]<0.000186%Region<0.00001Guangdong province2−0.84 [−0.89, −0.79]<0.000010%Other provinces9−0.36 [−0.55, −0.17]0.000287%HDL- CAll comparisons50.32 [0.03, 0.62]0.0397%Course of treatment0.0002<8 w11.06 [0.72, 1.40]<0.00001NA≥8 w40.17 [−0.14, 0.48]0.2797%Region0.0002Guangdong province11.06 [0.72, 1.40]<0.00001NAOther provinces40.17 [−0.14, 0.48]0.2797%LDL-CAll comparisons4−0.72 [−1.10, −0.34]0.000271%Course of treatment0.02<8 w1−1.17 [−1.57, −0.77]<0.00001NA≥8 w3−0.56 [−0.87, −0.24]0.000540%Region0.02Guangdong province1−1.17 [−1.57, −0.77]<0.00001NAOther provinces3−0.56 [−0.87, −0.24]0.000540%Total effective rateAll comparisons191.40 [1.32, 1.48]<0.0000118%Age0.72<60 y141.39 [1.31, 1.48]<0.0000127%≥60 y51.43 [1.26, 1.62]<0.000010%Different control treatment0.45Gliquidone31.35 [1.22, 1.50]<0.0000115%Other treatments161.42 [1.32, 1.51]<0.0000126%Course of treatment0.37<8 w101.44 [1.32, 1.58]<0.0000111%≥8 w91.37 [1.27, 1.47]<0.0000128%Region0.79Guangdong province51.41 [1.27, 1.58]<0.0000154%Other provinces141.39 [1.30, 1.48]<0.000017%


### 3.4.2. 24 h UPQ

13 RCTs [15–17, 19, 20, 23, 24, 26, 29, 31, 35–37] (including 1,054 patients) reported the data of 24 UPQ. Significant heterogeneity was found in these 13 RCTs (χ2 = 760.27, p<0.00001, I2 = 98%; Figure 6), so the REM was used. The 24 h UPQ for patients treated with Wuling powder combined with conventional western medicine was higher than that in the control group (WMD = -1.30; 95% CI [−1.82, −0.78], p<0.00001; Figure 6). Because of the large heterogeneity, the subgroup analysis was conducted based on the age, control treatment, duration of treatment, and region; and significant differences were found in intervention effects of different ages (p=0.002), control treatments (p<0.0001), and regions (p<0.0001). It was reflected in the glipizide group (control treatment) (χ2 = 0.1, p=0.95, I2 = 0%) and in Guangdong province (region) (χ2 = 0.36, p=0.55, I2 = 0%), while significant heterogeneity was still observed in the rest (Table 3, Supplementary Material Figures 3–6).Figure 6
Forest plot for 24 h UPQ.


### 3.4.3. Scr

14 RCTs [15, 17–19, 21, 24, 27–29, 31, 35–38] (including 1,210 participants) reported the Scr data. Significant heterogeneity was found (χ2 = 3628.59, p<0.00001, I2 = 100%; Figure 7), so the meta-analysis was conducted by using a REM. The analysis showed a statistically significant difference in Scr between the treatment and control groups (WMD = −10.17; 95% CI [−11.13, −9.21], p<0.00001; Figure 7), indicating that the Scr was significantly better in the treatment group. In addition, the subgroup analysis was conducted in different durations of treatment and regions, and different durations of treatment showed no statistically significant difference (p=0.11) and different regions showed statistically obvious difference (p=0.007), but significant heterogeneity was still observed (Table 3, Supplementary Material Figures 7 and 8).Figure 7
Forest plot of Scr.


### 3.4.4. BUN

10 RCTs [15, 19, 21, 24, 27, 28, 31, 35, 36, 38] (including 965 patients) reported the BUN data. The tests showed significant heterogeneity (χ2 = 137.59, p<0.00001, I2 = 93%; Figure 8), so the meta-analysis was conducted by using a REM. The analysis showed a statistically significant difference in BUN between the treatment and control groups (WMD = −1.62; 95% CI [−2.30, −0.93], p<0.00001; Figure 8), indicating that the BUN was significantly better in the treatment group. Subgroup analysis in different durations of treatment and regions showed no significant difference in intervention effects between the two groups (p=0.26 and 0.41 respectively), but significant heterogeneity was still observed (Table 3, Supplementary Material Figures 9 and 10).Figure 8
Forest plot of BUN.


### 3.4.5. UAER

6 RCTs [18, 20, 21, 27, 28, 38] (including 482 patients) reported on UAER. Tests showed significant heterogeneity (χ2 = 128.55, p<0.00001, I2 = 96%; Figure 9), so a REM was used. A statistically significant difference was found in UAER between the treatment and control groups (WMD = −24.73; 95% CI [−35.46, −13.99], p<0.00001; Figure 9), indicating that the UAER was significantly better in the treatment group. A subgroup analysis suggested the intervention effect was not significantly different in age (p=0.11) and duration of treatment (p=0.93) but showed an obvious difference in regions (p=0.02), with no heterogeneity in the Guangdong region (χ2 = 0.24, p=0.62, I2 = 0%) and the rest still observed significant heterogeneity (Table 3, Supplementary Material Figures 11–13).Figure 9
Forest plot of UAER.


### 3.4.6. FBG

11 RCTs [15, 18, 20, 23, 26, 28, 29, 31, 34–36] (including 1,013 patients) reported the FBG data. Tests showed significant heterogeneity (χ2 = 38.24, p<0.0001, I2 = 74%; Figure 10), so a REM was adopted for meta-analysis. The analysis results revealed a statistically significant difference in FBG between the treatment and control groups (WMD = −0.63; 95% CI [−0.97, −0.30], p=0.002; Figure 10), suggesting that Wuling powder combined with conventional western medicine may significantly reduce the FBG in DN patients. Based on different ages, control treatments, durations of treatment, regions, and safety, the subgroup analysis was conducted, and the results showed no significant differences in intervention effects (p=0.49, 0.45, 0.49, 0.67, and 0.78, respectively); no heterogeneity was found in the ≥60 years group (χ2 = 0.26, p=0.61, I2 = 0%) in the age subgroup and in Guangdong Province (χ2 = 0.26, p=0.61, I2 = 0%) in the region, while significant heterogeneity was still observed in the rest (Table 3, Supplementary Material Figures 14–18).Figure 10
Forest plot of FBG.


### 3.4.7. Glycated Hemoglobin

6 RCTs [18, 23, 27, 34–36] (including 467 patients) reported the glycated hemoglobin. A REM was adopted because significant heterogeneity was found among them (χ2 = 11.16, p=0.05, I2 = 55%; Figure 11). The glycated hemoglobin between the treatment and control groups was statistically significant (WMD = −0.11; 95% CI [−0.30, 0.08], p=0.26; Figure 11), indicating that it was significantly better in patients treated with the Wuling powder combined with conventional western medicine. Subgroup analysis showed no significant difference in intervention effects in age (p=0.56) and region (p=0.01), with no heterogeneity in Guangdong Province (χ2 = 0.32, p=0.57, I2 = 0%), while significant heterogeneity was still observed in the rest (Table 3, Supplementary Material Figures 19 and 20).Figure 11
Forest plot of glycated hemoglobin.


### 3.4.8. Blood Lipids

(1) 9 RCTs [15–18, 20, 21, 26, 29, 36] (856 patients) reported the TC and high heterogeneity was found (χ2 = 228.38, p<0.00001, I2 = 96%; Figure 12). The REM analysis results showed the TC was statistically significant (WMD = −0.63; 95% CI [−1.23, −0.04], p=0.04; Figure 12). In the subgroup analysis, the differences in age, control treatment, duration of treatment, and region (p=0.06, 0.22, 0.05, and 0.99, respectively) were not statistically significant (Table 3, Supplementary Material Figures 21–24).Figure 12
Forest plot of TC.(2) 11 RCTs [15–18, 20, 21, 26, 28, 29, 35, 36] (994 patients) reported TG values and the heterogeneity was high (χ2 = 222.98, p<0.00001, I2 = 96%; Figure 13). The REM analysis results showed (WMD = −0.46; 95% CI [−0.70, −0.23], p=0.0001; Figure 13) the differences in TG between the two groups were statistically significant. In the subgroup analysis, the differences were not statistically significant in age, control treatment, and duration of treatment (p=0.08, 0.11, and 0.7, respectively), were statistically significant in regions (p<0.00001), and not heterogeneous in Guangdong Province (p=0.69, I2 = 0%) (Table 3, Supplementary Material Figures 25–28).Figure 13
Forest plot of TG.(3) RCTs [18, 21, 28, 29, 35] (384 patients) recorded HDL values with a test for heterogeneity (χ2 = 137.26, p<0.00001, I2 = 97%; see Figure 14), indicating high heterogeneity, and using a random effects model, the results showed (WMD = −0.32; 95% CI [0.03,0.62], p=0.03; see Figure 14), the difference between the two groups was statistically significant. In the subgroup analysis, the differences were statistically significant across sessions and regions (all p=0.0002) (Table 3, Supplementary Material Figures 29 and 30).Figure 14
Forest plot of HDL.(4) 4 RCTs [18, 21, 28, 29] (314 patients) recorded LDL values, and the heterogeneity among them was proved to be high (χ2 = 10.28, p=0.02, I2 = 71%; Figure 15), which became lower after the study by Chen et al. [21] was removed (χ2 = 3.34, p = 0.19, I2 = 40%; Figure 15), so the difference between the two groups was statistically significant using a FEM (WMD = −0.57; 95% CI [−0.77, −0.37], p<0.00001). In the subgroup analysis, the differences were statistically significant in control treatment and region (all p=0.02) (Table 3, Supplementary Material Figures 31 and 32).Figure 15
Forest plot of LDL.In summary, Wuling powder showed better performance compared with the conventional methods in the treatment of DN in terms of TC, TG, HDL-C, and LDL-C.


### 3.4.9. TER

The TER was categorized as markedly effective, effective, and ineffective according to the improvement degree in clinical symptoms and related indicators (mainly 24 h urine volume, 24 h UPQ, Scr, BUN, UAER, and FBG). 19 RCTs [15–17, 20–22, 24, 25, 27–34, 36–38] involving 1,657 patients undertook the TER as an outcome indicator. As there was no significant heterogeneity (χ2 = 21.92, p=0.24, I2 = 18%; Figure 16), an FEM was used. The analysis showed that Wuling powder resulted in a significant increase in TER compared to conventional treatment (RR = 1.40; 95% CI [1.32, 1.48]; p<0.00001; Figure 16). Subgroup analysis based on age, control treatment, duration of treatment, and region showed no significant differences (p=0.72, 0.45, 0.37, and 0.79, respectively) (Table 3, Supplementary Material Figures 33–36).Figure 16
Forest plot of TER.


## 3.4.1. 24 h Urine Volume

6 RCTs [16, 17, 24, 25, 32, 37] involving 334 DN patients provided data on 24 h urine volume before and after the intervention. A heterogeneity test (P = 0.03 and I2 = 59%) and a sensitivity analysis revealed that the statistical heterogeneity became lower after the study of Wang et al. [32] was removed (χ2 = 5.16, p=0.27, I2 = 23%; Figure 5), so the FEM was used. The results showed that the 24 h urine volume was significantly higher for patients in the treatment group treated with Wuling powder combined with conventional western medicine (WMD = 357.95; 95% CI [322.83, 393.06], p<0.00001; Figure 5). The subgroup analysis suggested that, in the different age subgroups (p=0.01), the group <60 years (χ2 = 3.52, p=0.32, I2 = 15%) was homogeneous with the group ≥60 years (χ2 = 0.56, p=0.45, I2 = 0%), and the difference was statistically significant. The difference between different regional subgroups (p=0.14) was not significant (Table 3, Supplementary Material Figures 1 and 2).Figure 5
Forest plot of 24 h urine volume.Table 3
Subgroup analysis.
Number of comparisonsResultsP value for overall effectI 2P value for subgroup difference24h urine volumeWMD (95% CI)All comparisons6335.13 [295.01, 375.26]<0.0000159%Age0.01<60 y4360.83 [320.76, 400.91]<0.0000115%≥60y2310.13 [309.15, 311.10]<0.000010%Region0.14Beijing2240.47 [109.29, 371.65]0.00030%Other provinces4344.68 [299.76, 389.59]<0.0000173%24h UPQAll comparisons13−1.30 [−1.82, −0.78]<0.0000198%Age0.002<60 y12−1.44 [−2.01, −0.87]<0.0000199%≥60 y1−0.44 [−0.69, −0.19]0.0005NADifferent control treatment<0.0001Gliquidone3−0.45 [−0.54, −0.35]<0.000010%Other treatments10−2.15 [−2.95, −1.35]<0.0000199%Course of treatment0.05<8 w5−2.63 [−4.16, −1.11]0.000799%≥8 w8−1.00 [−1.53, −0.47]0.000298%Region<0.00001Guangdong province2−117.95 [−129.88, −106.02]<0.000010%Other provinces11−0.90 [−1.28, −0.52]<0.0000197%SCrAll comparisons14−10.17 [−11.13, −9.21]<0.00001100%Course of treatment0.11<8 w6−2.44 [−2.99, −1.89]<0.0000199%≥8 w8−11.16 [−21.76, −0.57]0.0498%Region0.007Guangdong province4−19.36 [−27.52, −11.20]<0.0000190%Other provinces10−8.12 [−9.10, −7.13]<0.00001100%BUNAll comparisons10−1.62 [−2.30, −0.93]<0.0000193%Course of treatment0.26<8 w4−2.01 [−2.79, −1.23]<0.0000181%≥8 w6−1.40 [−2.12, −0.67]0.000286%Region0.41Guangdong province4−1.32 [−2.16, −0.48]0.00283%Other provinces6−1.86 [−2.83, −0.89]0.000295%UAERAll comparisons6−24.73 [−35.46, −13.99]<0.0000196%Age0.11<60 y5−22.49 [−34.09, −10.89]0.000197%≥60 y1−38.41 [−53.97, −22.85]<0.00001NACourse of treatment0.93<8 w2−24.55 [−40.91, −8.18]0.00399%≥8 w4−25.73 [−44.46, −7.00]0.00789%Region0.02Guangdong province2−32.79 [−35.33, −30.25]<0.000010%Other provinces4−20.21 [−30.58, −9.84]0.000188%FBGAll comparisons11−0.63 [−0.97, −0.30]0.000274%Age0.49<60 y9−0.69 [−1.13, −0.25]0.00279%≥60 y2−0.52 [−0.76, −0.28]<0.00010%Different control treatment0.45Gliquidone3−0.87 [−1.72, −0.03]0.0470%Other treatments8−0.52 [−0.85, −0.20]0.00268%Course of treatment0.49<8 w1−0.84 [−1.38, −0.30]0.002NA≥8 w10−0.61 [−0.98, −0.25]0.00176%Region0.67Guangdong province2−0.73 [−1.07, −0.39]<0.00010%Other provinces9−0.61 [−1.04, −0.19]0.00578%Safety0.78No adverse effects9−0.62 [−0.96, −0.28]0.000472%Adverse effects2−0.88 [−2.71, 0.95]0.3489%HbA1CAll comparisons6−0.11 [−0.30, 0.08]0.2655%Age0.56<60 y5−0.08 [−0.34, 0.18]0.5764%≥60 y1−0.17 [−0.35, 0.01]0.07NARegion0.01Guangdong province2−0.35 [−0.55, −0.14]0.00080%Other provinces40.02 [−0.19, 0.23]0.8740%TCAll comparisons9−0.63 [−1.23, −0.04]<0.000196%Age0.06<60 y8−0.72 [−1.36, −0.07]0.0397%≥60 y10.06 [−0.42, 0.54]0.81NADifferent control treatment0.22Gliquidone3−0.14 [−1.00, 0.73]0.7592%Other treatments6−0.88 [−1.68, −0.08]0.0397%Course of treatment0.05<8 w3−1.70 [−3.24, −0.16]0.0399%≥8 w6−0.10 [−0.56, 0.35]0.6588%Region0.99Guangdong province2−0.64 [−2.98, 1.69]0.5999%Other provinces7−0.63 [−1.23, −0.02]0.0496%TGAll comparisons11−0.46 [−0.70, −0.23]0.000196%Age0.08<60 y10−0.50 [−0.74, −0.25]<0.000196%≥60 y1−0.05 [−0.49, 0.39]0.82NADifferent control treatment0.11Gliquidone3−0.27 [−0.45, −0.09]0.00356%Other treatments8−0.55 [−0.83, −0.26]0.000295%Course of treatment0.7<8 w3−0.38 [−0.89, 0.13]0.1498%≥8 w8−0.49 [−0.72, −0.25]<0.000186%Region<0.00001Guangdong province2−0.84 [−0.89, −0.79]<0.000010%Other provinces9−0.36 [−0.55, −0.17]0.000287%HDL- CAll comparisons50.32 [0.03, 0.62]0.0397%Course of treatment0.0002<8 w11.06 [0.72, 1.40]<0.00001NA≥8 w40.17 [−0.14, 0.48]0.2797%Region0.0002Guangdong province11.06 [0.72, 1.40]<0.00001NAOther provinces40.17 [−0.14, 0.48]0.2797%LDL-CAll comparisons4−0.72 [−1.10, −0.34]0.000271%Course of treatment0.02<8 w1−1.17 [−1.57, −0.77]<0.00001NA≥8 w3−0.56 [−0.87, −0.24]0.000540%Region0.02Guangdong province1−1.17 [−1.57, −0.77]<0.00001NAOther provinces3−0.56 [−0.87, −0.24]0.000540%Total effective rateAll comparisons191.40 [1.32, 1.48]<0.0000118%Age0.72<60 y141.39 [1.31, 1.48]<0.0000127%≥60 y51.43 [1.26, 1.62]<0.000010%Different control treatment0.45Gliquidone31.35 [1.22, 1.50]<0.0000115%Other treatments161.42 [1.32, 1.51]<0.0000126%Course of treatment0.37<8 w101.44 [1.32, 1.58]<0.0000111%≥8 w91.37 [1.27, 1.47]<0.0000128%Region0.79Guangdong province51.41 [1.27, 1.58]<0.0000154%Other provinces141.39 [1.30, 1.48]<0.000017%


## 3.4.2. 24 h UPQ

13 RCTs [15–17, 19, 20, 23, 24, 26, 29, 31, 35–37] (including 1,054 patients) reported the data of 24 UPQ. Significant heterogeneity was found in these 13 RCTs (χ2 = 760.27, p<0.00001, I2 = 98%; Figure 6), so the REM was used. The 24 h UPQ for patients treated with Wuling powder combined with conventional western medicine was higher than that in the control group (WMD = -1.30; 95% CI [−1.82, −0.78], p<0.00001; Figure 6). Because of the large heterogeneity, the subgroup analysis was conducted based on the age, control treatment, duration of treatment, and region; and significant differences were found in intervention effects of different ages (p=0.002), control treatments (p<0.0001), and regions (p<0.0001). It was reflected in the glipizide group (control treatment) (χ2 = 0.1, p=0.95, I2 = 0%) and in Guangdong province (region) (χ2 = 0.36, p=0.55, I2 = 0%), while significant heterogeneity was still observed in the rest (Table 3, Supplementary Material Figures 3–6).Figure 6
Forest plot for 24 h UPQ.


## 3.4.3. Scr

14 RCTs [15, 17–19, 21, 24, 27–29, 31, 35–38] (including 1,210 participants) reported the Scr data. Significant heterogeneity was found (χ2 = 3628.59, p<0.00001, I2 = 100%; Figure 7), so the meta-analysis was conducted by using a REM. The analysis showed a statistically significant difference in Scr between the treatment and control groups (WMD = −10.17; 95% CI [−11.13, −9.21], p<0.00001; Figure 7), indicating that the Scr was significantly better in the treatment group. In addition, the subgroup analysis was conducted in different durations of treatment and regions, and different durations of treatment showed no statistically significant difference (p=0.11) and different regions showed statistically obvious difference (p=0.007), but significant heterogeneity was still observed (Table 3, Supplementary Material Figures 7 and 8).Figure 7
Forest plot of Scr.


## 3.4.4. BUN

10 RCTs [15, 19, 21, 24, 27, 28, 31, 35, 36, 38] (including 965 patients) reported the BUN data. The tests showed significant heterogeneity (χ2 = 137.59, p<0.00001, I2 = 93%; Figure 8), so the meta-analysis was conducted by using a REM. The analysis showed a statistically significant difference in BUN between the treatment and control groups (WMD = −1.62; 95% CI [−2.30, −0.93], p<0.00001; Figure 8), indicating that the BUN was significantly better in the treatment group. Subgroup analysis in different durations of treatment and regions showed no significant difference in intervention effects between the two groups (p=0.26 and 0.41 respectively), but significant heterogeneity was still observed (Table 3, Supplementary Material Figures 9 and 10).Figure 8
Forest plot of BUN.


## 3.4.5. UAER

6 RCTs [18, 20, 21, 27, 28, 38] (including 482 patients) reported on UAER. Tests showed significant heterogeneity (χ2 = 128.55, p<0.00001, I2 = 96%; Figure 9), so a REM was used. A statistically significant difference was found in UAER between the treatment and control groups (WMD = −24.73; 95% CI [−35.46, −13.99], p<0.00001; Figure 9), indicating that the UAER was significantly better in the treatment group. A subgroup analysis suggested the intervention effect was not significantly different in age (p=0.11) and duration of treatment (p=0.93) but showed an obvious difference in regions (p=0.02), with no heterogeneity in the Guangdong region (χ2 = 0.24, p=0.62, I2 = 0%) and the rest still observed significant heterogeneity (Table 3, Supplementary Material Figures 11–13).Figure 9
Forest plot of UAER.


## 3.4.6. FBG

11 RCTs [15, 18, 20, 23, 26, 28, 29, 31, 34–36] (including 1,013 patients) reported the FBG data. Tests showed significant heterogeneity (χ2 = 38.24, p<0.0001, I2 = 74%; Figure 10), so a REM was adopted for meta-analysis. The analysis results revealed a statistically significant difference in FBG between the treatment and control groups (WMD = −0.63; 95% CI [−0.97, −0.30], p=0.002; Figure 10), suggesting that Wuling powder combined with conventional western medicine may significantly reduce the FBG in DN patients. Based on different ages, control treatments, durations of treatment, regions, and safety, the subgroup analysis was conducted, and the results showed no significant differences in intervention effects (p=0.49, 0.45, 0.49, 0.67, and 0.78, respectively); no heterogeneity was found in the ≥60 years group (χ2 = 0.26, p=0.61, I2 = 0%) in the age subgroup and in Guangdong Province (χ2 = 0.26, p=0.61, I2 = 0%) in the region, while significant heterogeneity was still observed in the rest (Table 3, Supplementary Material Figures 14–18).Figure 10
Forest plot of FBG.


## 3.4.7. Glycated Hemoglobin

6 RCTs [18, 23, 27, 34–36] (including 467 patients) reported the glycated hemoglobin. A REM was adopted because significant heterogeneity was found among them (χ2 = 11.16, p=0.05, I2 = 55%; Figure 11). The glycated hemoglobin between the treatment and control groups was statistically significant (WMD = −0.11; 95% CI [−0.30, 0.08], p=0.26; Figure 11), indicating that it was significantly better in patients treated with the Wuling powder combined with conventional western medicine. Subgroup analysis showed no significant difference in intervention effects in age (p=0.56) and region (p=0.01), with no heterogeneity in Guangdong Province (χ2 = 0.32, p=0.57, I2 = 0%), while significant heterogeneity was still observed in the rest (Table 3, Supplementary Material Figures 19 and 20).Figure 11
Forest plot of glycated hemoglobin.


## 3.4.8. Blood Lipids

(1) 9 RCTs [15–18, 20, 21, 26, 29, 36] (856 patients) reported the TC and high heterogeneity was found (χ2 = 228.38, p<0.00001, I2 = 96%; Figure 12). The REM analysis results showed the TC was statistically significant (WMD = −0.63; 95% CI [−1.23, −0.04], p=0.04; Figure 12). In the subgroup analysis, the differences in age, control treatment, duration of treatment, and region (p=0.06, 0.22, 0.05, and 0.99, respectively) were not statistically significant (Table 3, Supplementary Material Figures 21–24).Figure 12
Forest plot of TC.(2) 11 RCTs [15–18, 20, 21, 26, 28, 29, 35, 36] (994 patients) reported TG values and the heterogeneity was high (χ2 = 222.98, p<0.00001, I2 = 96%; Figure 13). The REM analysis results showed (WMD = −0.46; 95% CI [−0.70, −0.23], p=0.0001; Figure 13) the differences in TG between the two groups were statistically significant. In the subgroup analysis, the differences were not statistically significant in age, control treatment, and duration of treatment (p=0.08, 0.11, and 0.7, respectively), were statistically significant in regions (p<0.00001), and not heterogeneous in Guangdong Province (p=0.69, I2 = 0%) (Table 3, Supplementary Material Figures 25–28).Figure 13
Forest plot of TG.(3) RCTs [18, 21, 28, 29, 35] (384 patients) recorded HDL values with a test for heterogeneity (χ2 = 137.26, p<0.00001, I2 = 97%; see Figure 14), indicating high heterogeneity, and using a random effects model, the results showed (WMD = −0.32; 95% CI [0.03,0.62], p=0.03; see Figure 14), the difference between the two groups was statistically significant. In the subgroup analysis, the differences were statistically significant across sessions and regions (all p=0.0002) (Table 3, Supplementary Material Figures 29 and 30).Figure 14
Forest plot of HDL.(4) 4 RCTs [18, 21, 28, 29] (314 patients) recorded LDL values, and the heterogeneity among them was proved to be high (χ2 = 10.28, p=0.02, I2 = 71%; Figure 15), which became lower after the study by Chen et al. [21] was removed (χ2 = 3.34, p = 0.19, I2 = 40%; Figure 15), so the difference between the two groups was statistically significant using a FEM (WMD = −0.57; 95% CI [−0.77, −0.37], p<0.00001). In the subgroup analysis, the differences were statistically significant in control treatment and region (all p=0.02) (Table 3, Supplementary Material Figures 31 and 32).Figure 15
Forest plot of LDL.In summary, Wuling powder showed better performance compared with the conventional methods in the treatment of DN in terms of TC, TG, HDL-C, and LDL-C.


## 3.4.9. TER

The TER was categorized as markedly effective, effective, and ineffective according to the improvement degree in clinical symptoms and related indicators (mainly 24 h urine volume, 24 h UPQ, Scr, BUN, UAER, and FBG). 19 RCTs [15–17, 20–22, 24, 25, 27–34, 36–38] involving 1,657 patients undertook the TER as an outcome indicator. As there was no significant heterogeneity (χ2 = 21.92, p=0.24, I2 = 18%; Figure 16), an FEM was used. The analysis showed that Wuling powder resulted in a significant increase in TER compared to conventional treatment (RR = 1.40; 95% CI [1.32, 1.48]; p<0.00001; Figure 16). Subgroup analysis based on age, control treatment, duration of treatment, and region showed no significant differences (p=0.72, 0.45, 0.37, and 0.79, respectively) (Table 3, Supplementary Material Figures 33–36).Figure 16
Forest plot of TER.


## 3.5. Adverse Effects

Adverse reactions were reported in 2 out of 24 RTCs. The adverse reactions reported in the study by Shen and Shu [23] were nausea, vomiting, abdominal distension, diarrhea, skin rash, and mild hypoglycemia; while those reported by Jing et al. [28] included nausea, vomiting, back pain, skin pruritus, swelling of lower limbs, thirst, and excessive drinking. No adverse reactions were reported in the remaining RCTs.


## 3.6. Publication Bias

Funnel plots were plotted for studies with >10 literature on combined outcome indicators, and 24 h urine volume, 24 h UPQ, Scr, BUN, UAER, FBG, glycated hemoglobin, TC, TG, HDL-C, LDL-C, and TER after treatment showed significant asymmetry in the funnel plots (Figures17–28), indicating publication bias in the included studies.Figure 17
The publication bias funnel chart of 24 h urine volume.Figure 18
The publication bias funnel chart of 24 h UPQ.Figure 19
The publication bias funnel chart of Scr.Figure 20
The publication bias funnel chart of BUN.Figure 21
The publication bias funnel chart of UAER.Figure 22
The publication bias funnel chart of FBG.Figure 23
The publication bias funnel chart of glycated hemoglobin.Figure 24
The publication bias funnel chart of TC.Figure 25
The publication bias funnel chart of TG.Figure 26
The publication bias funnel chart of HDL-C.Figure 27
The publication bias funnel chart of LDL-C.Figure 28
The publication bias funnel chart of TER.


## 3.7. Certainty of Evidence

The GRADEpro was employed to assess the certainty of the evidence in this study. Table4 showed that the results of 24 h urine output, LDL, and TER were moderate-quality evidence, while other outcomes were low-quality evidences. The high heterogeneity of some outcomes, the low methodological quality, and the high risk of bias were reasons for the poor quality of the evidence. Therefore, Wuling powder should be considered cautiously in the clinical use for DN treatment.Table 4
Certainty of evidence: Wuling powder compared to control treatment for DN. CI, confidence interval; MD, mean difference; RR, risk ratio.
Certainty assessment№ of patientsEffectCertaintyImportance№ of studiesStudy designRisk of biasInconsistencyIndirectnessImprecisionOther considerationsWuling powderPlaceboRelative (95% CI)Absolute (95% CI)24 h urine volume5Randomized trialsSeriousNot seriousNot seriousNot seriousNone122122—MD 357.95 higher (322.83 higher to 393.06 higher)⨁⨁⨁◯ ModerateCRITICAL24 h UPQ13Randomized trialsSeriousSeriousNot seriousNot seriousNone547507—MD 1.3 lower (1.82 lower to 0.78 lower)⨁⨁◯◯ LowCRITICALSCr14Randomized trialsSeriousSeriousNot seriousNot seriousNone626584—MD 10.17 lower (11.13 lower to 9.21 lower)⨁⨁◯◯ LowCRITICALBUN10Randomized trialsSeriousSeriousNot seriousNot seriousNone504461—MD 1.62 lower (2.3 lower to 0.93 lower)⨁⨁◯◯ LowCRITICALUAER6Randomized trialsSeriousSeriousNot seriousNot seriousNone242240—MD 24.73 lower (35.46 lower to 13.99 lower)⨁⨁◯◯ LowCRITICALFBG11Randomized trialsSeriousSeriousNot seriousNot seriousNone525488—MD 0.63 lower (0.97 lower to 0.3 lower)⨁⨁◯◯ LowIMPORTANTHbA1C6Randomized trialsSeriousSeriousNot seriousNot seriousNone232235—MD 0.11 lower (0.3 lower to 0.08 higher)⨁⨁◯◯ LowIMPORTANTTC9Randomized trialsSeriousSeriousNot seriousNot seriousNone449407—MD 0.63 lower (1.23 lower to 0.04 lower)⨁⨁◯◯ LowIMPORTANTTG11Randomized trialsSeriousSeriousNot seriousNot seriousNone518476—MD 0.46 lower (0.7 lower to 0.23 lower)⨁⨁◯◯ LowIMPORTANTHDL5Randomized trialsSeriousSeriousNot seriousNot seriousNone193191—MD 0.32 higher (0.03 higher to 0.62 higher)⨁⨁◯◯ LowIMPORTANTLDL3Randomized trialsSeriousNot seriousNot seriousNot seriousNone112113—MD 0.57 lower (0.77 lower to 0.37 lower)⨁⨁⨁◯ ModerateIMPORTANTOverall effective rate19Randomized trialsSeriousNot seriousNot seriousNot seriousNone758/849 (89.3%)515/808 (63.7%)RR 1.40 (1.32 to 1.48)255 more per 1,000 (from 204 more to 306 more)⨁⨁⨁◯ModerateCRITICAL


## 4. Discussion

### 4.1. Results

As one of the common vascular disease complications in DM patients, DN seriously affects the prognosis of patients and should be treated as early as possible. In recent years, TCM has become an essential adjunctive drug treatment for most Chinese patients with DN due to its stable efficacy and low side effects. Many studies confirm that the combination of Wuling powder with conventional symptomatic supportive treatment for DN is effective in alleviating the clinical symptoms, improving renal function, stabilizing FBG, and lowering TG. It is safe and reliable with good clinical application and promotion value.This study included 24 studies and found that Wuling powder exerted a positive effect on the clinical management of DN. This meta-analysis study provided a sound theoretical basis for the application of Wuling powder in the treatment of DN. Therefore, the results of this study may provide an important reference for the adjuvant treatment of DN with TCM.Although our results were statistically significant, some of the results were subject to greater heterogeneity. The outcome markers were divided into subgroups based on characteristics of the patients such as different age, control treatment, duration of treatment, and region for comparison to seek reasons for heterogeneity. In the subgroup analysis, 24 h urine volume reduced heterogeneity after different age subgroup analysis, 24 h urine protein quantification reduced heterogeneity after control treatment and regional subgroup analysis, urine albumin excretion rate reduced heterogeneity after regional subgroup analysis, FBG reduced heterogeneity after age and regional subgroup analysis, and glycated hemoglobin and TG both reduced heterogeneity after regional subgroup analysis. It is worth noting that most of the outcome indicators showed lower heterogeneity in the Guangdong region, which may be related to the origin of the herbs. In contrast, significant heterogeneity was observed in Scr and BUN. The subgroup analysis was performed and there were no significant differences in intervention effects between groups, and the size of such heterogeneity was not reduced following the use of a REM.It is believed that these heterogeneities arise from the following points. Firstly, the reasons for the large heterogeneity are most likely related to the variety, origin, harvesting season, storage and processing, dosage form, and route of administration of the herbal medicines. Such contents are not described in detail in the literature, So they could not be analyzed further in this study. Secondly, only 24 relevant studies were included in this study, and most of them only mentioned the word simple randomisation without considering the specific implementation methods, which affected the scientific validity of the study results. In addition, three studies [31, 34, 36] reported allocation concealment and only one study [31] reported the use of a double-blind trial. The rest studies did not report the allocation concealment and were unblinded, which was susceptible to a variety of artifacts and may lead to heterogeneity with different study participants and various interventions. The randomization grouping resulted in selective bias, which could reduce the overall quality of the meta-analysis. Furthermore, some of the included studies did not mention the methods of testing for outcome indicators, and there were uncontrollable factors such as different experimental instruments, which affected the objectivity of the results. In addition, one study [34] had a shedding of participant data, which may affect the final analysis of the results. Meanwhile, some of the outcome indicators were combined despite high heterogeneity, which affected the reliability of the study. Taken together, these may have contributed to the high heterogeneity of some of the outcome indicators.In addition, many other factors were evident in this study in terms of their impacts on the results. Firstly, the studies included in this study were limited to English and Chinese, and the final analysis was conducted on all Chinese literature, which would result in a potential publication bias. While evidence-based treatment is a core aspect of TCM interventions, TCM places importance on the etiology of the disease. The studies included in this study tended to apply a specific drug without considering the individuality, diversity, and complexity of the DN, making it difficult to determine whether people in different studies had achieved true evidence-based treatment. Therefore, it is one of the larger reasons why the results were affected. In addition, there were different conventional Western medical treatments in the included studies. For example, some patients may also receive conventional treatments such as hypotension and lipid-lowering depending on their conditions. However, some of the studies failed to explain in detail what kind of Western medical treatment was adopted. In addition, whether the dose was controlled strictly would also be another factor resulting in publication bias. Clinical trials are concerned with the follow-up of patients’ long-term outcomes. Most of the included studies were limited to a short-term treatment after the drug intervention, which also impacts the bias in outcome efficacy. In the subgroup analysis, the cut-off points for age and duration of disease were mainly based on relevant studies, however, more biological support is needed. Finally, the funnel plot showed the publication bias in this study, which may be due to the ease of publishing positive results and the difficulty of publishing negative results, severely limiting the validity and objectivity of the efficacy of Wuling powder to treat DN. In addition, the results of the GRADE analysis showed that the reliability of the outcome indicators was mostly low to moderate. Therefore, Wuling powder could be cautiously recommended as an adjunctive treatment for DN.


### 4.2. Strengths and Limitations

The strengths of this study could be summarized as follows. Firstly, this was probably the first meta-analysis to assess the efficacy and safety of Wuling powder in the treatment of DN. Secondly, all the literature included were RCTs, ensuring the credibility of the results of this study. Thirdly, the results of this study provided a new therapeutic option for the treatment of DN. The results of this study suggested that the combination of the Wuling powder with conventional treatment for DN had positive clinical implications, which was superior to the Western medicine treatment alone. It implied that Wuling powder may enhance the effectiveness of conventional treatment and improve the overall clinical outcome, reflecting the uniqueness and superiority of TCM. Due to the holistic treatment theory, the use of TCM in the adjunctive treatment of disease is increasingly reported and researched. It is found that TCM can play a better therapeutic advantage in the treatment of both DN and its complications, and exert a positive effect on the safety, suffering reduction, and life improvement of patients. Systematically assessing the efficacy of TCM in DN and providing corresponding evidence-based medical evidence are of high significance to promote the TCM culture worldwide and search for new breakthroughs in the treatment of DN patients.However, there are some limitations to this study. Firstly, it was limited by the quality of the literature. Most of the studies included in the study did not report allocation concealment and the use of blinding, leading to the measurement and implementation of various biases. Secondly, the included studies were RCTs with small samples and were of low quality. Thirdly, the lack of DN staging in most of the studies in this study affected the effectiveness of Wuling powder in patients with different degrees of DN. In addition, the lack of a placebo prevented us from analysing the difference in efficacy between using and not using Wuling powder. Finally, the patients in this study were all selected from the Chinese region and may not be globally representative, with some degree of clinical bias applied.


## 4.1. Results

As one of the common vascular disease complications in DM patients, DN seriously affects the prognosis of patients and should be treated as early as possible. In recent years, TCM has become an essential adjunctive drug treatment for most Chinese patients with DN due to its stable efficacy and low side effects. Many studies confirm that the combination of Wuling powder with conventional symptomatic supportive treatment for DN is effective in alleviating the clinical symptoms, improving renal function, stabilizing FBG, and lowering TG. It is safe and reliable with good clinical application and promotion value.This study included 24 studies and found that Wuling powder exerted a positive effect on the clinical management of DN. This meta-analysis study provided a sound theoretical basis for the application of Wuling powder in the treatment of DN. Therefore, the results of this study may provide an important reference for the adjuvant treatment of DN with TCM.Although our results were statistically significant, some of the results were subject to greater heterogeneity. The outcome markers were divided into subgroups based on characteristics of the patients such as different age, control treatment, duration of treatment, and region for comparison to seek reasons for heterogeneity. In the subgroup analysis, 24 h urine volume reduced heterogeneity after different age subgroup analysis, 24 h urine protein quantification reduced heterogeneity after control treatment and regional subgroup analysis, urine albumin excretion rate reduced heterogeneity after regional subgroup analysis, FBG reduced heterogeneity after age and regional subgroup analysis, and glycated hemoglobin and TG both reduced heterogeneity after regional subgroup analysis. It is worth noting that most of the outcome indicators showed lower heterogeneity in the Guangdong region, which may be related to the origin of the herbs. In contrast, significant heterogeneity was observed in Scr and BUN. The subgroup analysis was performed and there were no significant differences in intervention effects between groups, and the size of such heterogeneity was not reduced following the use of a REM.It is believed that these heterogeneities arise from the following points. Firstly, the reasons for the large heterogeneity are most likely related to the variety, origin, harvesting season, storage and processing, dosage form, and route of administration of the herbal medicines. Such contents are not described in detail in the literature, So they could not be analyzed further in this study. Secondly, only 24 relevant studies were included in this study, and most of them only mentioned the word simple randomisation without considering the specific implementation methods, which affected the scientific validity of the study results. In addition, three studies [31, 34, 36] reported allocation concealment and only one study [31] reported the use of a double-blind trial. The rest studies did not report the allocation concealment and were unblinded, which was susceptible to a variety of artifacts and may lead to heterogeneity with different study participants and various interventions. The randomization grouping resulted in selective bias, which could reduce the overall quality of the meta-analysis. Furthermore, some of the included studies did not mention the methods of testing for outcome indicators, and there were uncontrollable factors such as different experimental instruments, which affected the objectivity of the results. In addition, one study [34] had a shedding of participant data, which may affect the final analysis of the results. Meanwhile, some of the outcome indicators were combined despite high heterogeneity, which affected the reliability of the study. Taken together, these may have contributed to the high heterogeneity of some of the outcome indicators.In addition, many other factors were evident in this study in terms of their impacts on the results. Firstly, the studies included in this study were limited to English and Chinese, and the final analysis was conducted on all Chinese literature, which would result in a potential publication bias. While evidence-based treatment is a core aspect of TCM interventions, TCM places importance on the etiology of the disease. The studies included in this study tended to apply a specific drug without considering the individuality, diversity, and complexity of the DN, making it difficult to determine whether people in different studies had achieved true evidence-based treatment. Therefore, it is one of the larger reasons why the results were affected. In addition, there were different conventional Western medical treatments in the included studies. For example, some patients may also receive conventional treatments such as hypotension and lipid-lowering depending on their conditions. However, some of the studies failed to explain in detail what kind of Western medical treatment was adopted. In addition, whether the dose was controlled strictly would also be another factor resulting in publication bias. Clinical trials are concerned with the follow-up of patients’ long-term outcomes. Most of the included studies were limited to a short-term treatment after the drug intervention, which also impacts the bias in outcome efficacy. In the subgroup analysis, the cut-off points for age and duration of disease were mainly based on relevant studies, however, more biological support is needed. Finally, the funnel plot showed the publication bias in this study, which may be due to the ease of publishing positive results and the difficulty of publishing negative results, severely limiting the validity and objectivity of the efficacy of Wuling powder to treat DN. In addition, the results of the GRADE analysis showed that the reliability of the outcome indicators was mostly low to moderate. Therefore, Wuling powder could be cautiously recommended as an adjunctive treatment for DN.


## 4.2. Strengths and Limitations

The strengths of this study could be summarized as follows. Firstly, this was probably the first meta-analysis to assess the efficacy and safety of Wuling powder in the treatment of DN. Secondly, all the literature included were RCTs, ensuring the credibility of the results of this study. Thirdly, the results of this study provided a new therapeutic option for the treatment of DN. The results of this study suggested that the combination of the Wuling powder with conventional treatment for DN had positive clinical implications, which was superior to the Western medicine treatment alone. It implied that Wuling powder may enhance the effectiveness of conventional treatment and improve the overall clinical outcome, reflecting the uniqueness and superiority of TCM. Due to the holistic treatment theory, the use of TCM in the adjunctive treatment of disease is increasingly reported and researched. It is found that TCM can play a better therapeutic advantage in the treatment of both DN and its complications, and exert a positive effect on the safety, suffering reduction, and life improvement of patients. Systematically assessing the efficacy of TCM in DN and providing corresponding evidence-based medical evidence are of high significance to promote the TCM culture worldwide and search for new breakthroughs in the treatment of DN patients.However, there are some limitations to this study. Firstly, it was limited by the quality of the literature. Most of the studies included in the study did not report allocation concealment and the use of blinding, leading to the measurement and implementation of various biases. Secondly, the included studies were RCTs with small samples and were of low quality. Thirdly, the lack of DN staging in most of the studies in this study affected the effectiveness of Wuling powder in patients with different degrees of DN. In addition, the lack of a placebo prevented us from analysing the difference in efficacy between using and not using Wuling powder. Finally, the patients in this study were all selected from the Chinese region and may not be globally representative, with some degree of clinical bias applied.


## 5. Conclusion

In conclusion, Wuling powder combined with conventional drugs showed outstanding efficacy and positive effect in the treatment of DN. However, there were still some limitations in this systematic evaluation, so applying Wuling powder in clinical treatment should be considered cautiously. Therefore, some clinical studies with larger samples, higher study quality, and more rigorous study design should be taken in the future to validate the accurate and objective assessment of DN, and then obtain more valuable meta-analysis results, providing more reliable and effective new ideas for the treatment of DN.



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*Source: 1720749-2022-09-30.xml*