CRD summary: This review of randomised trials concluded that rosiglitazone use for at least 12 months is associated with a significantly increased risk of myocardial infarction and heart failure, but not cardiovascular mortality, in patients with impaired glucose tolerance or type 2 diabetes. These conclusions appear appropriate given the evidence presented.

CRD commentary: This was a generally well-conducted review that was based on a question clearly defined in terms of the interventions, participants, study designs and outcomes. PubMed/MEDLINE and other appropriate sources were searched for relevant primary studies, though inclusion was limited to English language publications; therefore the potential for language bias cannot be entirely ruled out. To minimise the potential for error and bias, two reviewers were independently involved at key stages of the review process. The studies were synthesised using appropriate methods, although details of the validity assessment criteria were lacking, and attempts were made to assess statistical heterogeneity and the robustness of the review findings. The authors' conclusions appear appropriate given the evidence presented in the review.