Thirty RCTs were included in the review (18,022 patients).
By endpoint, vildagliptin was statistically significantly more effective at reducing mean HbA1c levels than control treatments (WMD -32%, 95% CI -0.44 to -0.19; 30 trials; Ι²=96%), particularly when placebo was compared with daily vildagliptin regimens of 50mg (WMD -0.58%, 95% CI -0.72 to -0.44; 11 trials; Ι²=63%) and 100mg (WMD -0.77%, 95% CI -0.96 to -0.58; 10 trials; Ι²=82%). Compared with metformin, daily vildagliptin regimens of 100mg were statistically significantly less effective for reducing HbA1c levels (WMD 0.30, 95% CI 0.15 to 0.46; four trials; Ι²=51%). Other comparisons revealed 100mg vildagliptin regimens to have been less effective than thiazolidinediones or sulphonylureas, but more effective than α-glucosidase inhibitors for reducing HbA1c levels. None of these differences were statistically significant.
Statistically significant increases in body weight were observed when vildagliptin regimens of 100mg/day were compared with placebo (WMD 0.95 kg, 95% CI 0.73 to 1.17; ten trials; Ι²=0%), metformin (WMD 1.54 kg, 95% CI 0.73 to 2.36; four trials; Ι²=78%) and α-glycosidase inhibitors (WMD 1.19, 95% CI 0.84 to 1.55; two trials; Ι²=94%). Statistically significant reductions in body weight were observed when vildagliptin regimens of 100mg were compared with thiazolidinediones (WMD -1.55, 95% CI -2.10 to -1.01; five trials; Ι²=76%) and sulphonylureas (WMD - 1.40, 95% CI -1.78 to -1.02; four trials; Ι²=69%). Body weight was increased with 100mg vildapgliptin compared with α-glucosidase inhibitors but the difference was not statistically significant.
Compared with placebo, mean fasting plasma glucose was statistically significantly reduced with daily vildagliptin regimens of 50mg (WMD -0.57, 95% CI -0.76 to -0.38; ten trials; Ι²=12%) and 100mg (WMD -0.96, 95% CI -1.26 to -0.65; nine trials; Ι²=49%). A reduction was also demonstrated when vildagliption (100mg/day) was compared with α-glucosidase inhibitors but this difference was not statistically significant. Statistically significant increases in mean fasting plasma glucose was observed for vildagliptin (100mg/day) in comparison with thiazolidinediones (WMD 0.75, 95% CI 0.45 to 1.05; six trials; Ι²=74%), metformin (WMD 0.69, 95% CI 0.41 to 0.96; three trials; Ι²=40%), and sulphonylureas (WMD 0.17, 95% CI 0.04 to 0.30; four trials; Ι²=0%).
Borderline statistically significant reductions in overall risk of adverse events were found for vildagliptin compared with α-glucosidase inhibitors (RR 0.77, 95% CI 0.61 to 0.97; two trials), sulphonylureas (RR 0.95, 95% CI 0.91 to 0.99; three trials), and metformin (RR 0.92, 95% CI 0.88 to 0.97; four trials). Similar results were found when vildagliptin was compared with sulphonylureas for incidence of serious adverse events (RR 0.85, 95% CI 0.73 to 0.99; three trials), and with metformin for discontinuation due to adverse events (RR 0.61, 95% CI 0.40 to 0.92; four trials). Risk of hypoglycaemia was significantly lower for vildagliptin over sulphonylureas (RR 0.25, 0.10 to 0.64; four trials), but no statistically significant differences in risk were observed between both regimens of vildagliptin (50mg/day and 100mg/day) and placebo.