Patterns of statin use and long‐term adherence and persistence among older adults with diabetes

Abstract

Statins reduce the risk of cardiovascular disease in patients with diabetes. This study examined the prevalence of statin use and assessed long-term adherence and persistence among people aged ≥65 years with diabetes. Pharmaceutical Benefits Scheme data covering a 10% random sample of the Australian population were analyzed. Among older adults with diabetes, the yearly prevalence of statin use was compared via Poisson regression modeling using 2006 as the reference year. A cohort of 7400 new statin users (mean age 72.9 years; 46.2% female) was followed longitudinally. Adherence was assessed via the proportion of days covered (PDC). Statin discontinuation was defined as the first ≥90 days without statin coverage. The prevalence of statin use increased from 52.0% in 2006 to 71.2% in 2016 (age and sex-adjusted rate ratio 1.37; 95% confidence interval 1.33-1.41). No gender differences in statin use were observed, but the likelihood of being dispensed statin decreased with increasing age. Among the longitudinal cohort, the proportion adherent (PDC ≥0.80) decreased from 54.0% at 6 months to 37.0% at 9 years. Over a mean follow-up of 4.9 years, 66.8% discontinued, and the likelihood of stopping statin medication within the first year was 42.7%. No age or gender differences in statin discontinuation were evident. Statin use has increased among older adults with diabetes. However, adherence is low and discontinuation is high. Further investigations into the factors associated with non-adherence or discontinuation of statins are important so as to optimize statin use towards achieving the intended cardiovascular benefits among older people with diabetes.