A Prospective Observational Study to Compare the Efficacy and Adverse Effects of Glimepiride and Vildagliptin Added to Metformin in Type 2 Diabetes Mellitus

Abstract

Introduction: In order to prevent the specific diabetes mellitus related macrovascular and microvascular complications, guidelines by American Diabetes Association recommend a reasonable glycosylated haemoglobin goal for non-pregnant adults to be less than 7% (53 mmol/mol). The common practice recently is to use a sulfonylurea like glimepiride or selective Dipeptidyl Peptidase-4 (DPP-4) inhibitor like vildagliptin as addon therapy to metformin when the latter alone fails to achieve the target level of sugar control. Many randomised clinical trials have demonstrated the comparative efficacy of glimepiride and vildagliptin as add-on therapy to metformin. But their results might not always reflect what actually could be expected in clinical practice. Aim: To compare the efficacy and safety of glimepiride and vildagliptin as add-on therapy to metformin in achieving glycaemic control and also to compare the common adverse effects observed. Materials and Methods: This prospective observational study was conducted among adult type 2 diabetes mellitus patients who did not achieve adequate glycaemic control with metformin monotherapy. Patients were purposively selected in a way so that 30 patients received 2 mg of glimepiride once daily and 30 received 50 mg of vildagliptin twice daily as add-on therapy to metformin 1.5 to 2 gm in single or divided doses. Fasting, post-prandial sugar and glycosylated hemoglobin levels were re-examined after 4 to 6 months. Data were analysed using SPSS version 20.0. Paired and unpaired T-tests were applied to compare the parametric data and z-test was used to compare the difference between two proportions at 5% significance level. Results: In both the groups there was a significant reduction in mean FBS, PPBS levels and HbA1c% from the baseline (p0.05). However, glimepiride plus metformin reduced mean HbA1c% significantly more than vildagliptin plus metformin (p<0.001). The glimepiride group caused significantly more hypoglycaemia than the vildagliptin group (p=0.03) while vildagliptin group was significantly more associated with overall gastrointestinal symptoms (p=0.046). There was no significant difference in weight gain between the two groups (p=0.084). Conclusion: Glimepiride appeared to be superior to vildagliptin in reducing the HbA1c level but at the cost of significantly more episodes of hypoglycaemia than vildagliptin while latter added to metformin produced significantly more gastrointestinal side effects than the former.

Keywords

• dipeptidyl peptidase-4 inhibitor
• glycosylated haemoglobin
• metformin combination therapy
• sulfonylurea