The initial search strategy identified 3,048 studies but 3,041 were excluded since they were not randomised or did not report relevant outcomes. The remaining 7 studies included data for 20,191 patients with follow up periods ranging from 12 to 48 months.
Heart failure was reported in 2.3% (214/9360) of patients given a glitazone and in 1.4% (146/10,831) of those given a comparator. The relative risk was 1.72 (95% CI 1.21 to 2.42, p = 0.002). The risk of cardiovascular death was not changed by the glitazones (0·93, 95% CI 0·67-1·29, p=0·68).
This study concludes that, "heart failure in patients given glitazones might not carry the risk that is usually associated with congestive heart failure". It should be noted that this study did not carry out an analysis of myocardial infarction. The existing body of evidence also indicates that cardiovascular mortality is unchanged by the glitazones but rosiglitazone appears to significantly increase the risk of myocardial infarction. Continued concerns regarding the safety of the glitazones means that new reviews of glitazone safety are likely to be published.
Action: Clinicians should consider glitazones to be a third line choice after metformin and sulphonylureas.