Prevalence and Incidence of Statin Use and 3-Year Adherence and Discontinuation Rates Among Older Adults With Dementia.

Objective: To examine the patterns of statin use and determine the 3-year adherence and discontinuation rates among a cohort of Australians aged ≥65 years with dementia.

Methods: The yearly prevalence and incidence of statin use were compared via Poisson regression modeling using 2007 as the reference year. People with dementia were identified according to dispensing of antidementia medications. A cohort of 589 new statin users was followed longitudinally. Adherence was estimated via the proportion of days covered (PDC). Discontinuation was defined as ≥90 days without statin coverage.

Results: The annual prevalence of statin use among older Australians with dementia increased from 20.6% in 2007 to 31.7% in 2016 (aged-sex adjusted rate ratio: 1.51, 95% confidence interval: 1.35-1.69). Among the new users, the proportion adherent (PDC ≥ 0.80) decreased from 60.3% at 6 months to 31.0% at 3 years. During the 3-year follow-up, 58.7% discontinued their statin.

Conclusions: Despite increased use of statins among older Australians with dementia, adherence is low and discontinuation is high, which may point to intentional cessation.