Comparison of antioxidative effect of metformin and combination of metformin-sulfonylurea in type 2 diabetes mellitus patients

Background: Even though oxidative stress is intensively studied for its role in diabetic nephropathy, the effectiveness of first-line medication on diabetes in preventing oxidative stress and diabetic nephropathy is still unknown. This study aimed to analyze 8-iso-Prostaglandin F2α, UACR, and their correlation on 114 type 2 diabetes mellitus patients who consumed metformin and the combination of metformin-sulfonylurea. Material and Method: Urinary 8-iso-Prostaglandin F2α was measured by ELISA and urinary albumin was measured by Bromocresol Green Albumin assay. Results: The results showed that HbA1c (p=0.038) and 8-iso-Prostaglandin F2α level higher in the combination group than in metformin group, but not for UACR (p=0.838). However, subgroup analysis on albuminuric patients (UACR>30 mg/g, n=55) showed no different in HbA1c and 8-iso-Prostaglandin F2α level between the medication groups. Linear regression analysis showed HbA1c (β=0.402, p=0.002) and the combination of metformin-sulfonylurea (β=0.364, p=0.004) were the most predictive factors for increased UACR after controlled by age, gender, IMT, systolic blood pressure, 8-iso-Prostaglandin F2α, smoking habit and exercise habit. Conclusion: In conclusion, metformin was more effective in decreasing 8-iso-Prostaglandin F2α level, an oxidative stress marker. The increase of HbA1c and the use of a combination of metformin-sulfonylurea contributed in increased UACR in this study.