Abstract 205: Association of Statin Use With the Risk of Subarachnoid Hemorrhage in Medicare Patients With Unruptured Cerebral Aneurysms

Abstract

Background: Animal studies have demonstrated that statins decrease cerebral aneurysm progression and the risk of subarachnoid hemorrhage (SAH). A protective effect has also been observed in human studies of abdominal aortic aneurysms. We investigated the association between statin use and SAH in Medicare beneficiaries. Methods: We used the 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-adjusted logistic models to investigate the association of statin use with the risk of SAH, out-of-hospital death, and undergoing intervention more than 3 months after the diagnosis (as a marker of disease progression), as well as the composite outcome of all events. Results: We identified 27,574 patients with unruptured cerebral aneurysms (average age 72.3 years, 72.7% female); mean follow up was 29.8 months. Statins were used by 41.4%. Overall, 1,497 patients developed SAH and 725 underwent intervention (coiling or clipping) before aneurysm rupture. Current or recent statin use was not associated with decreased risk of SAH (OR 1.05, 95% CI 0.93 to 1.17), even after stratification on tobacco use/chronic pulmonary disease. Similarly, no association was observed between statin use and the likelihood for operative intervention (OR 0.89, 95% CI 0.75 to 1.10). The risk of the composite outcome was lower among ongoing statin users, compared to remote or no users (OR 0.72, 95% CI 0.68 to 0.77). Conclusions: Use of statins by patients with unruptured cerebral aneurysms was not associated with decreased risk of SAH. This underscores the differences in human physiology from the animal models used. The lack of the protective effect of statins seen in aortic aneurysms may be explained by the non-atherosclerotic nature of cerebral aneurysms. Funding: National Institute on Aging (PO1- AG19783).