Risk of Bias in Systematic Reviews of Non-Randomized Studies of Adverse Cardiovascular Effects of Thiazolidinediones and Cyclooxygenase-2 Inhibitors: Application of a New Cochrane Risk of Bias Tool

Ref ID	10
First Author	A. Bilandzic
Journal	PLOS MEDICINE
Year Of Publishing	2016
URL	https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1001987
Keywords	• Risk of bias • Cardiology • Observational studies • Cochrane
Problem(s)	• Inclusion of observational / non-randomised studies • Meta-analyses and forest plots presented without considering risk of bias / quality • Flawed risk of bias undertaken
Number of systematic reviews included	2
Summary of Findings	The Cochrane Risk of Bias tool highlighted a wide range of risks of bias in observational studies included in the two widely cited included systematic reviews and this had the potential to change the conclusions of the reviews. The pooled odds ratios for myocardial infarction, heart failure, and death for rosiglitazone versus pioglitazone remained significantly elevated when analyses were confined to studies with low or moderate Risk of Bias. However, the estimate for myocardial infarction declined from 1.14 (95% CI 1.07–1.24) to 1.06 (95% CI 0.99–1.13) when analysis was confined to studies with low Risk of Bias. Estimates of pooled relative risks of cardiovascular events with COX-2 inhibitors compared with no nonsteroidal anti-inflammatory drug changed little when analyses were confined to studies with low or moderate Risk of Bias. The exception was a rise in the relative risk associated with ibuprofen from 1.07 (95% CI 0.97–1.18) to 1.14 (95% CI 1.03–1.26).
Did the article find that the problem(s) led to qualitative changes in interpretation of the results?	Yes
Are the methods of the article described in enough detail to replicate the study?	Yes