Comparative Effectiveness of Pioglitazone and Rosiglitazone in Type 2 Diabetes, Prediabetes,and the Metabolic Syndrome: A Meta-Analysis

To assess the comparative efficacy and safety of pioglitazone and rosiglitazone.Multiple electronic databases were searched for randomized, controlled trials (RCTs) of efficacy or effectiveness and for studies of any design which reported adverse events. Pooled estimates were calculated using a random effects model.Eighty-seven RCTs fulfilled our inclusion criteria for efficacy or effectiveness and 42 studies examined safety or tolerability. Two head-to-head RCTs of type 2 diabetes demonstrated significant improvements in A1c in both groups at follow-up with no significant difference between groups; a third study found no significant change in A1c in either group. The pooled estimate of effect on A1c for pioglitazone compared to placebo was -0.99% (95% confidence interval [CI], -1.18, -0.81) and for rosiglitazone was -0.92% (95% CI, -1.2, -0.64). Indirect comparison revealed no significant difference in A1c (between-drug difference -0.07% [95% CI, -0.41, 0.27]). Rosiglitazone increased total cholesterol compared to pioglitazone (net between-drug effect 13.91 mg/dl [95% CI, 1.20 to 26.62]). Both drugs increased weight by 2 to 3 kg and rates of adverse events were similar for the two drugs. Data were insufficient to assess comparative effects on health outcomes such as cardiovascular events.Based largely on indirect evidence, the two thiazolidinediones appear to have similar effects on glycemic control and similar side-effect profiles. Rosiglitazone may increase total cholesterol compared to pioglitazone. Studies are needed which provide direct comparisons between the two drugs, particularly for long-term health outcomes.