Association of Lung Function Indices with Inflammatory Marker (hsCRP) and Glycemic Control in Type 2 Diabetic Patients of Karachi
Authors: Kanpurwala Muhammad Adnan , Qureshi Masood A , Ayoob Zeenat , Shaikh Zaman 
Published: November 2023

Background/Objectives

Diabetes Mellitus type 2 is a serious chronic disease with increasing prevalence throughout the world. Almost every system of the body is affected by the disease. Lung function impairment has also appeared to be a complication of diabetes. The aim of this study is to assess the difference in the lung function indices and high sensitive C‐reactive protein (hsCRP) a inflammatory marker in diabetic patients as compared to the non diabetic individuals.

Methodology

73 Diabetics and 77 age matched Non Diabetics’ individuals, who were non smokers and had no apparent lung diseases were recruited. All subjects underwent screening with detailed history, anthropometry, high sensitive C‐reactive protein (hsCRP), glycosylated hemoglobin (HbA1c) and spirometric measurements.

Results

There was a significant reduction in the FVC [mean difference (95% CI) 0.495 L (0.27, 0.72) P < 0.001], FEV1 [mean difference (95% CI) 0.34 L (0.15, 0.53) P < 0.001], FEV1/FVC ratio [mean difference (95% CI) −0.018 (−0.036, −0.0003) P ≤ 0.05] and a significant increase in the hsCRP levels [mean difference (95% CI) 5.52 mg/L (3.1, 7.9) P < 0.001] in the diabetic subjects as compared to the healthy individuals. A statistical model was built using multivariable linear regression analysis to predict FVC. The model equation is as follows. FVC = β0 + β1(X1) + β2(X2) + β3(X3) + β4(X4) + β5(D).

Whereas, β0 = −2.78 (constant), X1=gender, X2=height, X3=age, X4=HbA1c, D‐ = duration of disease >10years. R2 value = 0.77

Female gender taken as reference, Duration of disease: ≤5 years (reference), 6 – 10 years (non significant) & > 10 years

Conclusion

It can be concluded from this study that type 2 diabetic individuals had statistically significant lower FVC and FEV1 and raised hsCRP values as compared to the non diabetics. The effect on the FVC was even more pronounced in diabetics who had inadequate glycemic control and prolonged duration of disease. Therefore, it is suggested that clinicians should assess the diabetic patients on annual follow up for early changes in lung functions through spirometry as this would help in reducing the morbidity and mortality associated with respiratory complications

Support or Funding Information

The study was approved and funded by Dow University of Health Sciences, Pakistan.

Anthropometric measurements of Diabetic and Non Diabetic

Variable
Non Diabetic (77)Meant ± SD
Diabetic (73)Meant ± SD

Weight (kg)
67.56 ± 12.54
70.56 ± 11.98

Height (cm)
167.43 ± 9.59
164.10 ± 8.62

Waist Circumference (cm)
89.43 ± 10.11
96.85 ± 9.79

Hip Circumference (cm)
96.60 ± 10.55
102.40 ± 10.01

BMI(kg/m2)
24.07 ± 3.79
26.19 ± 3.98

WHR
0.92 ± 0.07
0.95 ± 0.06

Univariate Linear Regression Analysis of Lung function Indices in liters with diabetic status, age, gender and anthropometric factors.

FVC
FEV1
FEV1FVC

Variables
B
SE
95%CI
R2
P value
B
SE
95%CI
R2
P value
B
SE
95% CI
R2
P value

Lower limit
Upper limit
Lower limit
Upper limit
Lower limit
Upper limit

Exposure Status a
0.495
0.116
−0.724
−0.266
0.110
<0.001
−0.343
0.095
−0.531
−0.155
0.081
<0.001
0.018
0.009
0.000
0.036
0.025
=0.025

Genderb
0.989
0.098
0.795
1.183
0.407
<0.001
0.781
0.080
0.622
0.940
0.389
<0.001
−0.007
0.010
−0.027
0.012
0.004
=0.440

Age (years)
−0.021
0.006
−0.340
−0.008
0.068
= 0.001
−0.017
0.005
−0.028
−0.007
0.071
=0.001
0.000
0.001
−0.001
0.001
0.002
=0.620

Weight (kg)
0.017
0.005
0.007
0.026
0.075
0.001
0.014
0.004
0.006
0.022
0.082
<0.001
0.007
0.000
0.000
0.001
0.000
=0.834

Height (cm)
0.059
0.005
−0.050
0.068
0.534
<0.001
0.045
0.004
0.039
0.054
0.499
<0.001
0.000
0.001
−0.002
0.000
0.010
=0.228

Waist Circumference (cm)
−0.009
−0.006
−0.020
−0.002
−0.017
= 0.111
−0.028
0.005
−0.017
0.001
0.019
=0.095
0.000
0.000
−0.001
0.001
0.001
=0.716

Hip Circumference (cm)
−0.010
0.006
−0.002
−0.001
0.021
= 0.074
−0.009
0.005
−0.018
0.000
0.024
=0.060
0.000
0.000
0.000
0.001
0.007
= 0.824

BMI(kg/m2)
−0.040
0.015
−0.069
−0.010
0.045
=0.009
−0.028
0.012
−0.052
−0.004
0.034
=0.023
0.001
0.001
−0.001
0.003
0.007
=0.312

WHR
0.426
0.967
−1.480
2.330
0.001
=0.660
0.276
0.781
−1.267
1.819
0.001
=0.724
−0.041
0.073
−0.186
0.104
0.002
=0.577

Duration of Diseasec (years)

= 5
−0.587
0.194
−0.971
−0.204
0.129
= 0.003
−0.435
0.159
−0.750
−0.121
0.101
=0.007
0.017
0.016
−0.014
0.048
0.027
= 0.270

6–10
−0.326
0.149
−0.620
−0.032
= 0.030
−0.203
0.122
−0.444
0.088
=0.098
0.014
0.012
−0.009
0.038
= 0.230

> 10
−0.652
0.163
−0.974
−0.331
<0.001
−0.462
.133
−.726
−199
= 0.001
0.023
0.013
−0.003
0.049
= 0.084

Multivariable Linear Regression Analysis for FVC (L) in Diabetic subjects

Variables
B
SE
95% CI
P Value

Lower limit
Upper limit

Gendera
0.436
0.108
0.220
0.652
<0.001

Height (cm)
0.043
0.006
0.030
0.056
<0.001

Age (years)
−0.026
0.005
−0.035
−0.016
<0.001

HbAlc (%)
−0.043
0.018
−0.078
−0.007
= 0.018

Duration of Diseaseb (years)

>10
−0.170
0.081
−0.332
−0.009
=0.039

FVC forced vital capacity B Coefficient of regression, SE standard error.

CI confidence interval.

Sample size 73 diabetic

All variables with insignificant correlation with FVC were excluded by using the stepwise method of multivariable regression analysis.

Female gender taken as reference

Duration of disease: =5 years (reference), 6–10 years (non significant) & > 10 years

Significant P Value <0.05

Constant −2.757

R2: 0.77

Adjusted R2:0.752

Dependent Variable: FVC in liters