Adverse drug effects observed with vildagliptin versus pioglitazone or rosiglitazone in the treatment of patients with type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials

Vildagliptin and pioglitazone/rosiglitazone are emerging Oral Hypoglycemic Agents (OHAs) which are used to treat patients suffering from Type 2 Diabetes Mellitus (T2DM). In this analysis, we aimed to systematically compare the adverse drug events which were observed with the use of vildagliptin versus pioglitazone or rosiglitazone respectively. Online databases were searched for studies comparing vildagliptin with pioglitazone/rosiglitazone. Adverse drug events were considered as the clinical endpoints in this analysis. We calculated Odds Ratios (OR) with 95% Confidence Intervals (CIs) using the RevMan 5.3 software. All the authors had full access to the data which were used and approved the final version of the manuscript. A total number of 2396 patients were analyzed (1486 and 910 patients were treated with vildagliptin and pioglitazone/rosiglitazone respectively). Vildagliptin and pioglitazone/rosiglitazone were both associated with similar overall adverse drug events (OR: 1.00, 95% CI: 0.81-1.24; P = 1.00). Headache (OR: 0.88, 95% CI: 0.60-1.27; P = 0.49) and upper respiratory tract infection (OR: 0.95, 95% CI: 0.71-1.27; P = 0.75) were similarly observed. However, dizziness was significantly lower with pioglitazone/rosiglitazone (OR: 0.63, 95% CI: 0.43-0.92; P = 0.02). Back pain, diarrhea and nausea were insignificantly lower with pioglitazone/rosiglitazone (OR: 0.81, 95% CI: 0.49-1.33; P = 0.40), (OR: 0.83, 95% CI: 0.48-1.44; P = 0.52) and (OR: 0.52, 95% CI: 0.25-1.05; P = 0.07) respectively, whereas peripheral edema and weight gain were insignificantly higher (OR: 1.21, 95% CI: 0.56-2.62; P = 0.63) and (OR: 2.29, 95% CI: 0.51-10.34; P = 0.28) respectively. Nevertheless, when pioglitazone and rosiglitazone were separately compared with vildagliptin, peripheral edema and weight gain were significantly higher with rosiglitazone (OR: 2.36, 95% CI: 1.40-3.99; P = 0.001) and (OR: 5.20, 95% CI: 2.47-10.92; P = 0.0001) respectively. Both vildagliptin and pioglitazone/rosiglitazone are acceptable for the treatment of patients with T2DM on the basis that they are not significantly different in terms of overall adverse drug events. However, weight gain and peripheral edema would have to be re-assessed in further larger randomized controlled trials.