Effects of pioglitazone on cardiovascular events and all-cause mortality in patients with type 2 diabetes: A meta-analysis of randomized controlled trials

Aim: In 2019, the Italian Society of Diabetology and the Italian Association of Clinical Diabetologists nominated an expert panel to develop guidelines for drug treatment of type 2 diabetes. After identifying the effects of glucose-lowering agents on major adverse cardiovascular events (MACEs), all-cause mortality, and hospitalization for heart failure (HHF) as critical outcomes, the experts decided to perform a systematic review and meta-analysis on the effect of pioglitazone with this respect. Data synthesis: A MEDLINE database search was performed to identify RCTs, up to June 1st, 2021, with duration≥52 weeks, in which pioglitazone was compared with either placebo or active comparators. The principal endpoints were MACE and HHF (restricted for RCT reporting MACEs within their outcomes), all-cause mortality (irrespective of the inclusion of MACEs among the pre-specified outcomes). Mantel-Haenszel odds ratio (MH-OR) with 95% Confidence Interval (95% CI) was calculated for all the endpoints considered. Eight RCTs were included in the analysis for MACEs and HF (5048 and 5117 patients in the pioglitazone and control group, respectively), and 24 in that for all-cause mortality (10,682 and 9674 patients). Pioglitazone neither significantly increased nor reduced the risk of MACE, all-cause mortality, and HHF in comparison with placebo/active comparators (MH-OR: 0.90, 95% CI 0.78-1.03, 0.91, 95% CI 0.77, 1.09, and 1.16, 95% CI 0.73, 1.83, respectively). Pioglitazone was associated with a significant reduction of MACE in patients with prior cardiovascular events (MH-OR 0.84, 95% CI 0.72-0.99). Conclusions: This meta-analysis showed no significant effects of pioglitazone on incident MACE, all-cause mortality, and HHF.