Effect of Metformin on Chronic Pain After Thoracic Surgery in Diabetic Patients

Study Overview
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Brief Summary
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Metformin has been found to have more and more functions as a commonly used hypoglycemic drug in clinic. It has been found that metformin has anti-inflammatory, anti-tumor and lipid metabolism regulating effects. Basic studies have shown that metformin as an adjuvant drug combined with gabapentin and tramadol is safe and effective in patients with neuropathic pain. Postoperative chronic pain as a common complication has seriously affected the quality of life and mood of patients after surgery.Some studies have shown that chronic pain after partial operation manifests as neuropathic pain. The effect of metformin on chronic pain after thoracic surgery in patients with diabetes mellitus was observed in this experiment, which was compared with patients taking insulin to control blood sugar.

Detailed Description
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The analgesic mechanism of metformin may include the following aspects:(1)Metformin relieves neuropathic pain mainly because it can activate adenosine monophosphate-activated protein kinase (AMPK), which plays a crucial role in pain regulation as an important endogenous kinase controlling energy metabolism.(2)In addition, metformin can also inhibit ERK signaling pathway, further inhibit sodium channel, prevent the development of peripheral sensitization and achieve the effect of relieving neuropathic pain. (3)Metformin has been shown to alleviate bone cancer pain in rats by reducing STAT3 phosphorylation.Clinical research in this field is limited to basic research and ethical requirements are rarely reported at home and abroad. Li Chunye et al. of Jiangsu University designed a clinical trial to compare the efficacy of metformin and gabapentin combined with tramadol on neuropathic pain. The results showed that metformin had a better effect. The incidence of chronic pain after thoracic surgery is higher. Postoperative chronic pain is a complex pain. The nature and mechanism of chronic pain after thoracic surgery are still controversial. Some studies have shown that some chronic pain after thoracic surgery manifests neuropathic pain, the mechanism may be related to surgical incision, nerve injury caused by trauma and increased pain sensitization. Can metformin alleviate chronic pain after surgery? The research on this aspect is still blank at present.This study was designed as a prospective cohort study to observe whether there was a difference in the incidence of chronic pain after thoracoscopic lobectomy between patients taking metformin and patients injecting insulin to control blood sugar.

Official Title
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Effect of Metformin on Chronic Pain After Thoracic Surgery in Diabetic Patients

Conditions
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Postoperative Chronic Pain

Intervention / Treatment
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* Drug: Metformin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged between 18 and 70 Diabetes history. Use metformin or insulin to control blood sugar The type of operation is selective thoracoscopic lobectomy. Exclusion Criteria: Newly diagnosed diabetic patients at admission Complication of severe cardiopulmonary diseases Refuse to participate in this experiment Participate in other trials Patients with diabetic complications (including diabetic nephropathy, peripheral neuropathy, etc.)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Metformin<br>Patients use metformin to control blood sugar | Drug: Metformin<br>* Patients use metformin to control blood sugar<br>|
| Insulin<br>Patients use Insulin to control blood sugar | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of chronic pain after operation | A VAS score greater than or equal to 3 is defined as the presence of chronic pain after surgery. | 3 months after operation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| VAS score at extubation time, 12 hours and 24 hours after operation | A VAS score greater than or equal to 3 is defined as the presence of pain after surgery. | extubation time, 12 hours and 24 hours after operation | 
| Neuropathic pain score and incidence at 3 months after operation | Assessment of the presence of neuropathic pain by using self-rating scale | 3 months after operation | 
| Anxiety and Depression Score | Assessment of Anxiety and Depression in Patients by HAMD Depression Scale | 3 months after operation | 
| Length of ICU stay | Some patients may need to be transferred to ICU. | an average of 2 days | 
| Length of hospital stay | Total length of hospitalization | an average of 10 days |