Adherence and Persistence Among Statin Users Aged 65 Years and Over: A Systematic Review and Meta-analysis

Background: Older people (aged >= 65 years) have distinctive challenges with medication adherence. However, adherence and persistence patterns among older statin users have not been comprehensively reviewed. Methods: As part of a broader systematic review, we searched Medline, Embase, PsycINFO, CINAHL, Database of Abstracts of Reviews of Effects, CENTRAL, and the National Health Service Economic Evaluation Database through December 2016 for English articles reporting adherence and/or persistence among older statin users. Data were analyzed via descriptive methods and meta-analysis using random-effect modeling. Results: Data from more than 3 million older statin users in 82 studies conducted in over 40 countries were analyzed. At 1-year follow-up, 59.7% (primary prevention 47.9%; secondary prevention 62.3%) of users were adherent (medication possession ratio [MPR] or proportion of days covered [PDC] >= 80%). For both primary and secondary prevention subjects, 1-year adherence was worse among individuals aged more than 75 years than those aged 65-75 years. At 3 and >= 10 years, 55.3% and 28.4% of users were adherent, respectively. The proportion of users persistent at 1-year was 76.7% (primary prevention 76.0%; secondary prevention 82.6%). Additionally, 68.1% and 61.2% of users were persistent at 2 and 4 years, respectively. Among new statin users, 48.2% were nonadherent and 23.9% discontinued within the first year. The proportion of statin users who were adherent based on self-report was 85.5%. Conclusions: There is poor short and long term adherence and persistence among older statin users. Strategies to improve adherence and reduce discontinuation are needed if the intended cardiovascular benefits of statin treatment are to be realized.