Effects of statin therapy on abdominal aortic aneurysm growth: a meta-analysis and meta-regression of observational comparative studies.

Abstract

To determine whether statin therapy reduces the growth rate of small abdominal aortic aneurysms (AAAs). A meta-analysis and a meta-regression of comparative studies. Eligible studies were randomized controlled trials or observational comparative studies of statin therapy versus placebo or no statin, enrolling individuals with small (<55 mm in diameter) AAAs and reporting AAA growth rate as an outcome. Study-specific estimates (standardized mean differences [SMDs]) were combined in the fixed- and random-effects model. Seven adjusted and 4 unadjusted observational comparative studies enrolling 4647 patients with a small AAA were identified. Pooled analysis of all 11 studies suggested a significant reduction in AAA growth rate among patients assigned to statin therapy versus no statin (SMD, -0.420; 95% confidence interval [CI], -0.651 to -0.189). Combining the 7 high-quality studies providing adjusted data for growth rates generated an attenuated but still statistically significant result favoring statin therapy (SMD, -0.367; 95% CI, -0.566 to -0.168). The meta-regression coefficient for the baseline diameter was statistically significant (-0.096; 95% CI, -0.132 to -0.061). Statin therapy is likely effective in prevention of the growth of small AAAs, and may be more beneficial as the baseline diameter increases.