The Effect of Preoperative Metformin on Postoperative Hyperglycemia in Non-Diabetic Patients: A Randomized Clinical Trial

Background: Blood glucose control during surgery can decrease the infection, disability, and death rate. The purpose of this study was to determine the effect of preoperative metformin on blood glucose levels in nondiabetic orthopedic surgery. Methods: This clinical trial was conducted on 176 nondiabetic patients with ASA class I or II who were candidates for orthopedic surgery. The patients were randomly divided into two equal groups. The metformin group received 500 mg metformin tablet orally and the placebo group received placebo tablet 30 minutes before the surgery. Blood glucose was measured every 6-hour to 24 hours and blood urine nitrogen (BUN), creatinine was measured preoperatively and the day after surgery. The data was analyzed by SPSS v21 and P value<0.05 was significant. Results: Demographic characteristics such as age, sex and body mass index (BMI) had no significant difference in two groups. Creatinine and BUN were similar in two groups. Preoperative blood glucose was 101.8±22.6 mg/dl in the metformin group and 109.7±24.8 mg/dl in the control group without significant difference (p=0.08). However, BS at hours 6, 12, showed a significant difference between the two groups (p<0.001, 0.022) and then blood glucose was similar in two groups (0.8, 0.12 respectively). Conclusion: Preoperative metformin (500 mg) was effective for blood glucose control in nondiabetic patients undergoing orthopedic surgery. However, additional research is required to determine the efficacy of this therapy.