Statin adherence patterns among older adults on triple therapy: a real-world study using group-based trajectory model

Aim: Older adults with dyslipidemia often have coexisting diabetes and hypertension, requiring triple therapy with statins, antihypertensives, and oral antidiabetics. Given that statin adherence is a key metric in the Medicare STAR Ratings program, understanding statin use in this population is critical. However, prior studies have focused on adherence to statin monotherapy or composite adherence to triple therapy, with limited evidence on statin-specific patterns in this population. Methods: We conducted a retrospective cohort study using a Texas-based Medicare Advantage database (2016–2017). Adults receiving concurrent triple therapy (statins, renin-angiotensin system antagonists, and oral antidiabetics) were followed for 12 months. Statin adherence was measured monthly using the proportion of days covered (PDC) and modeled using group-based trajectory modeling (GBTM). Multinomial logistic regression, informed by the Andersen behavioral model, was used to identify sociodemographic and clinical predictors of adherence trajectories. Results: Among 7,847 patients, three distinct statin adherence trajectories were identified: near-perfect adherence (57.0%), adherent (23.6%), and rapid decline (19.4%). Female sex was associated with higher odds of rapid decline than male sex. Younger age (≤ 65 years) and having at least one prior hospitalization were significant predictors of rapid adherence decline, whereas older age and a greater number of concomitant medications were associated with lower odds of decline. Notably, about 80% of patients were adherent to statin despite lower adherence to the overall triple-therapy regimen. Conclusions: This study identified three distinct statin adherence trajectories among older adults on triple therapy. By highlighting predictors of rapid adherence decline, including female sex and prior hospitalization, these findings can help clinicians identify high-risk patients and inform targeted interventions to improve adherence and cardiovascular outcomes.