Abstract 80: Patterns of Statin Use, Adherence, and Persistence among Elderly Patients with High-Risk Vascular Diseases

Abstract

BACKGROUND: High-risk vascular diseases (HRVD), including cerebrovascular disease (CVD), coronary artery disease with diabetes (CADD), acute coronary syndrome (ACS), and peripheral artery disease (PAD), are still the leading cause of death in the US, despite progress in treatment. Little research has been done to systematically study statin use patterns, adherence, and persistence for HRVD patients using real-world large claims databases. The objective was to examine statin use patterns, adherence, and persistence in elderly patients with HRVD. METHODS: A large US administrative claims database for over 10 million beneficiaries annually from more than 100 self-insured Fortune 500 companies was used to conduct a retrospective cohort study. Patients with HRVD, defined as CVD, PAD, CADD, or a history of ACS (≥30days through 365 days after discharge for ACS) between 10/01/2008 and 09/30/2009, were ≥65 years of age and identified with minimum 12-month pre-index and 24-month post-index health plan eligibility. Statin use, statin median/mean dose, percent of patients using maximal statin dose (defined as atorvastatin ≥80 mg and rosuvastatin ≥40 mg), and statin adherence (calculated using the medication possession ratio [MPR]) were measured at 6 months, 12 months, and 24 months. Persistence was assessed with survival analysis techniques using a ≥30-day gap to define a discontinuation. RESULTS: A total of 525,893 patients with HRVD were identified; 50.3% used statins during the baseline period (PAD: 44.9%; CVD: 45.2%; CADD: 63.9%; ACS: 61.7%). This number changed slightly to 49.2%, 51.8%, and 54.3% during the 6-month, 12-month, and 24-month follow-up periods, respectively, with PAD and CVD patients having greater increase of statin use (49.7%, 50%, respectively) during the 24-month follow-up period. Simvastatin (41.6%, 42.2%, 42.8%), atorvastatin (31.9%, 30.5%, 28.8%), and rosuvastatin (11.5%, 12.0%, 12.4%) were the most commonly used statins with 4.8%, 4.6%, and 4.3% of patients using maximum statin doses at 6-month, 12-month, and 24-month follow-up periods. There appeared to be few changes in statin doses during the 24-month follow-up period (mean/median dose: simvastatin 34.6/40 mg, 34.8/40 mg, 34.8/40 mg; atorvastatin 29.6/20 mg, 29.8/20 mg, 30.2/20 mg; rosuvastatin 14.1/10 mg, 14.2/10 mg, 14.4/10 mg). The mean/median MPR was 0.66/0.68, 0.67/0.74, and 0.60/0.65 among HRVD patients who used a statin with only 17.4%, 20.9 %, and 20.7% of patients adherent (MPR≥80%) to their statin therapy during the 6-month, 12-month, and 24-month follow-up periods, respectively. The median time to statin discontinuation was 406 days during the 24-month follow-up period. CONCLUSIONS: Statin adherence is suboptimal for elderly patients with HRVD and the patterns of statin adherence persist over time with little titration in doses.