Abstract 246: Statin Medication Adherence Among Medicare Beneficiaries

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Background: High low-density lipoprotein cholesterol (LDL-C) is a major risk factor for atherosclerotic cardiovascular disease (ASCVD). Statin therapy to lower LDL-C is recommended among specific high-risk populations; however, based on 2013 guidelines, less than 50% of those eligible are currently on statins. Older adults have a high burden of ASCVD; thus if prescribed, use and adherence to statins are a key part of preventing further morbidity and mortality. In this study, our primary objective was to describe adherence to generic and brand statins among Medicare Part D beneficiaries nationally and at the state level. Methods: Calendar year 2012 data were obtained for the Medicare Part D prescription drug file, which includes Medicare Advantage and Fee-for-service beneficiaries aged ≥65 years. Proportion of days covered (PDC) was calculated for enrollees with at least 2 statin fills on or after January 1, 2012 (first fill by October 1, 2012). PDC for statins was defined as total days’ supply divided by total eligible days (minus days as inpatient), multiplied by 100. Age-adjusted prevalence of being adherent (PDC ≥80%) was calculated overall and by state. State-based adjusted (i.e., for age, race/ethnicity, dual Medicare/Medicaid enrollee, and plan type) odds of adherence was determined using logistic regression, independently for generic and brand name statins. Results: Overall, 10.6 million beneficiaries using statins were included, with 80% on generic (adherence: 75.5%), 11% on brand (adherence: 66.2%), and 9% on a mix of generic and brand name (adherence: 71.7%) statins. Prevalence of adherence to generic was higher than brand statins across all sociodemographic variables. Age-adjusted prevalence of adherence to generic (68.6[DC]-83.7%[VT]) and brand name (60.1[MS]-81.9%[VT]) statins varied across states. Within state differences between prevalence of generic and brand statin adherence ranged from 1.28 (AK) to 15.11 (RI) percentage points (median: 8.44 for CT). State-based adjusted odds ratios of adherence to generic (range: aPR=.60, 95% CI [.60-.61] for NJ to aPR=1.33, 95%CI [1.29-1.37] for VT; CA median reference) and brand name (range: aPR=.64, 95%CI [.61-.67] for NV to aPR=1.82, 95%CI [1.76-1.88] for WV; KS median reference) statins varied. Conclusion: Almost three-fourths of beneficiaries were adherent to statins; however wide variation in adherence to generic versus brand statins within states and odds of adherence across states, reflects room for improvement. Greater costs of brand versus generic medications may be a contributing factor to lower adherence. The use of low-cost statins, coupled with clinician (e.g. counseling) and health care system (e.g. clinical decision supports) activities to promote medication adherence may be useful.