Abstract TP514: The Effect of Statin Adherence on Cardiovascular Outcomes After Ischemic Stroke in Statin Benefit Group: A Nested Case-Control Study

Abstract

Backgrounds: Irrespective of the indication for statin, statin adherence after ischemic stroke was associated with better clinical outcome. We studied the association between statin adherence and recurrent cardiovascular (CV) events among the patients with acute ischemic stroke and statin benefit. Methods: Using Comprehensive Registry Collaboration for Stroke in Korea (CRCS-K), patients with acute ischemic stroke were identified. Statin benefit was defined using the secondary prevention guidelines of American Stroke Association in 2014. The data for statin prescription after discharge were obtained from National Health Insurance Services (NHIS) claim data by matching with CRCS-K. Statin adherence was measured by the medication possession ratio (MPR), which was dichotomized, setting a threshold of MPR (<80%) to identify patients who were nonadherent. A nested case-control design was used to evaluate the occurrence of recurrent stroke, myocardial infarction, and all-cause mortality for 1 year after discharge. Each case was matched to 4 controls by age, sex, initial stroke severity and registry entry time. Adjusted conditional logistic regression models were used to estimate the odds ratio (OR) of CV events. Results: Among 11,768 patients in NHIS-CRCS-K matching database, 5,504 patients were the statin benefit group and prescribed with statin on discharge. Overall MPR for 1 year after discharge was 73.1%. Overall CV events for 1 year were 569, which was more prevalent in low adherence group. (MPR <80%, 18.0% vs. ≥80%, 6.5%, p<0.0001) In nested case-control data set, lower adherence to statin was associated with a higher risk of CV events compared with higher adherence (adjusted OR 1.496 [1.174-1.904]) after adjusting hypertension, diabetes mellitus, atrial fibrillation, history of stroke, history of antiplatelet drug use and discharge modified Rankin Scale score. Statin discontinuation was associated with higher risk compared with adequate statin prescription. (adjusted OR 2.075[1.622-2.655]) Conclusion: Adequate statin adherence in the patients with acute ischemic stroke and statin benefit was significantly associated with recurrent CV events.