Association of Statin Therapy with Risk of Epilepsy in Two Propensity Score-Matched Cohorts
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INTRODUCTION: In recent years, studies have suggested that statins may have a neuroprotective effect against epilepsy. Additionally, statins may lower risk of epilepsy through lowering the risk of stroke.3 However, evidence from rat models and case reports suggests an opposite effect. Overall data is limited and little is known about the incidence of epilepsy in healthy adults who are taking statins for primary preventions. OBJECTIVES: To examine the association between statin use and epilepsy risk in a general population cohort and a healthy population cohort (individuals with no severe comorbidities). METHODS: Patients were Tricare beneficiaries who were studied between October 2003 to March 2012. Based on patients' characteristics during baseline period (Fiscal Year [FY] 2004-2005), we formed 2 propensity scores (PS) matched cohorts of Statin-users and Non-users 1) a PS-matched General cohort, 2) a PS-matched Healthy cohort Our outcome was defined using a validated ICD-9 code for epilepsy inpatient or outpatient encounters during follow up period (FY 2006 - March 2012) . We calculated odds ratios (OR) and 95% confidence intervals (95% CI) for epilepsy during follow up. RESULTS: PS-matched General cohort matched 6342 Statin- users to 6342 Non-users, OR of epilepsy in this cohort during follow up was 0.91, 95%CI=0.67-1.23; PS-matched Healthy cohort matched 3351 Statin-users to 3351 Non-users. OR in the Healthy cohort during follow up was 1.08; 95%CI= 0.64-1.83. There was an increased prevalence of epilepsy in Non-users (0.6%) vs. Statin-users (0.3%) at baseline in the PS-matched Healthy cohort. (p=0.04) CONCLUSION: This study did not demonstrate a significant beneficial or deleterious effect of statin use on risk of being diagnosed with epilepsy. The increased prevalence of epilepsy in Non-users at baseline in the PS-matched Healthy cohort suggests that physicians might be avoiding statin prescription in patients with epilepsy, which may explain the apparent association of statins with less risk of epilepsy in some previous observational studies.