Statins and subarachnoid hemorrhage in Medicare patients with unruptured cerebral aneurysms

BackgroundStatins have been shown to decrease aneurysm progression and rupture in two experimental settings: animals with cerebral aneurysm and humans with abdominal aortic aneurysms. AimsTo investigate statin use and outcomes in humans with unruptured cerebral aneurysms through Medicare administrative data. MethodsWe used a 40% random sample Medicare denominator file and corresponding inpatient, outpatient (2003-2011), and prescription (2006-2011) claims to conduct a retrospective cohort study of patients diagnosed with unruptured cerebral aneurysms, between 2003 and 2011. We used propensity score-adjusted models to investigate the association between statin use and risk of subarachnoid hemorrhage. Secondary analyses repeated the main models stratified on tobacco use status and separately assessed other composite outcomes. ResultsWe identified 28931 patients with unruptured cerebral aneurysms (average age 720 years, 726% female); mean follow-up was 300 months; 413% used statins. Overall, 593 patients developed subarachnoid hemorrhage, and 703 underwent treatment before subarachnoid hemorrhage. Current or recent statin use was not associated with a difference in subarachnoid hemorrhage risk (odds ratio, 103; 95% conflict of interest 086-123); models stratified on tobacco use status were nearly identical. No association was observed between statin use and the composite outcome of subarachnoid hemorrhage or aneurysm treatment (odds ratio, 094; 95% conflict of interest, 084-106). The risk of subarachnoid hemorrhage or out-of-hospital death was lower among statin users (odds ratio, 069; 95% conflict of interest, 064-074). ConclusionsStatin use by patients with unruptured cerebral aneurysms was not associated with subarachnoid hemorrhage risk. Given the prior animal experimental studies demonstrating a protective effect, further prospective studies are needed to investigate the potential relationship.