Effects of Statin Therapy on Abdominal Aortic Aneurysm Growth: A Meta-analysis and Meta-regression of Observational Comparative Studies

ObjectiveTo determine whether statin therapy reduces the growth rate of small abdominal aortic aneurysms (AAAs).DesignA meta-analysis and a meta-regression of comparative studies.MaterialsEligible 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.MethodsStudy-specific estimates (standardized mean differences [SMDs]) were combined in the fixed- and random-effects model.ResultsSeven 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).ConclusionStatin therapy is likely effective in prevention of the growth of small AAAs, and may be more beneficial as the baseline diameter increases.