Effects of renin-angiotensin system blockades on cardiovascular outcomes in patients with diabetes mellitus: A systematic review and meta-analysis

Aim: To determine whether renin-angiotensin system (RAS) blockade is beneficial for cardiovascular outcomes in patients with diabetes mellitus (DM) using meta-analysis. Methods: The MEDLINE and Cochrane library databases were searched for randomized controlled trials published up to June 2010. We also reviewed reference lists from identified trials and review articles to identify any other relevant studies, and the ClinicalTrials.gov website to identify randomized controlled trials that were registered as completed but not yet published. A random-effects model was used to combine the estimates for risk ratios (RR). Results: Eligible studies were randomized controlled trials (including post hoc analyses) assessing the effects of angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers on cardiovascular events compared to controls in patients with DM. Nineteen clinical trials with 41,042 patients and 6039 cardiovascular events were identified. RAS blockade significantly reduced the risk of major cardiovascular events (RR 0.92, 95% confidence interval [CI] 0.84-1.00, I-2 statistic 53%) and myocardial infarction (RR 0.82, 95% CI 0.72-0.94, I-2 = 55%). There were trends towards fewer strokes and lower all-cause mortality but these were not statistically significant. Conclusions: The available evidence shows that treatment with RAS blockade can routinely be considered for diabetic patients to reduce major cardiovascular events. (C) 2011 Elsevier Ireland Ltd. All rights reserved.