Objectives To conduct a systematic review and meta-analysis of the effects of rosiglitazone treatment on cardiovascular risk and mortality using multiple data sources and varying analytical approaches with three aims in mind: to clarify uncertainties about the cardiovascular risk of rosiglitazone; to determine whether different analytical approaches are likely to alter the conclusions of adverse event meta-analyses; and to inform efforts to promote clinical trial transparency and data sharing.

Design Systematic review and meta-analysis of randomized controlled trials.

Data sources GlaxoSmithKline’s (GSK’s) ClinicalStudyDataRequest.com for individual patient level data (IPD) and GSK’s Study Register platforms, MEDLINE, PubMed, Embase, Web of Science, Cochrane Central Registry of Controlled Trials, Scopus, and ClinicalTrials.gov from inception to January 2019 for summary level data.

Eligibility criteria for selecting studies Randomized, controlled, phase II-IV clinical trials that compared rosiglitazone with any control for at least 24 weeks in adults.

Data extraction and synthesis For analyses of trials for which IPD were available, a composite outcome of acute myocardial infarction, heart failure, cardiovascular related death, and non-cardiovascular related death was examined. These four events were examined independently as secondary analyses. For analyses including trials for which IPD were not available, myocardial infarction and cardiovascular related death were examined, which were determined from summary level data. Multiple meta-analyses were conducted that accounted for trials with zero events in one or both arms with two different continuity corrections (0.5 constant and treatment arm) to calculate odds ratios and risk ratios with 95% confidence intervals.

Results 33 eligible trials were identified from ClinicalStudyDataRequest.com for which IPD were available (21 156 patients). Additionally, 103 trials for which IPD were not available were included in the meta-analyses for myocardial infarction (23 683 patients), and 103 trials for which IPD were not available contributed to the meta-analyses for cardiovascular related death (22 772 patients). Among 29 trials for which IPD were available and that were included in previous meta-analyses using GSK’s summary level data, more myocardial infarction events were identified by using IPD instead of summary level data for 26 trials, and fewer cardiovascular related deaths for five trials. When analyses were limited to trials for which IPD were available, and a constant continuity correction of 0.5 and a random effects model were used to account for trials with zero events in only one arm, patients treated with rosiglitazone had a 33% increased risk of a composite event compared with controls (odds ratio 1.33, 95% confidence interval 1.09 to 1.61; rosiglitazone population: 274 events among 11 837 patients; control population: 219 events among 9319 patients). The odds ratios for myocardial infarction, heart failure, cardiovascular related death, and non-cardiovascular related death were 1.17 (0.92 to 1.51), 1.54 (1.14 to 2.09), 1.15 (0.55 to 2.41), and 1.18 (0.60 to 2.30), respectively. For analyses including trials for which IPD were not available, odds ratios for myocardial infarction and cardiovascular related death were attenuated (1.09, 0.88 to 1.35, and 1.12, 0.72 to 1.74, respectively). Results were broadly consistent when analyses were repeated using trials with zero events across both arms and either of the two continuity corrections was used.

Conclusions The results suggest that rosiglitazone is associated with an increased cardiovascular risk, especially for heart failure events. Although increased risk of myocardial infarction was observed across analyses, the strength of the evidence varied and effect estimates were attenuated when summary level data were used in addition to IPD. Because more myocardial infarctions and fewer cardiovascular related deaths were reported in the IPD than in the summary level data, sharing IPD might be necessary when performing meta-analyses focused on safety.