Identifying adherent patients to newly initiated statins using previous adherence to chronic medications

BACKGROUND: Statins are one of the most frequently prescribed medications in the United States. Despite well-documented benefits in managing hyperlipidemia and reducing cardiovascular risks, statin adherence remains suboptimal. Several effective interventions have been implemented to improve adherence to statins. However, identifying patients who are at risk for developing poor medication adherence at the time of treatment initiation could assist in planning early targeted interventions. Studies have suggested that previous adherence to chronic medications is a strong predictor of future adherence to newly initiated medications. OBJECTIVE: To investigate patients' adherence to newly initiated statins by measuring previous adherence to angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs), and oral antidiabetic drugs (OADs). METHODS: A retrospective cohort study was conducted using administrative claims data from January 2016 to May 2018. New statin initiators were identified and included in the study if they were continuously enrolled in the health plan and had at least 1 prescription for ACEIs, ARBs, or OADs 1 year before statin initiation (pre-index period). Baseline adherence to ACEIs/ARBs, OADs, or both was calculated during a 1-year pre-index period using proportion of days covered (PDC) and defined as PDC ≥ 0.80. Adherence to statins was assessed 1 year after statin initiation and was the primary outcome, with a PDC ≥ 0.80 considered as adherent. Patient demographics were measured during the pre-index period. Multivariable logistic regression was conducted for each cohort separately to determine an association between baseline adherence and future statin adherence controlling for various demographic and clinical characteristics. RESULTS: 1,223 ACEI/ARB users, 714 OAD users, and 452 concomitant ACEI/ARB and OAD users were identified. In the regression model, adherence to baseline medications was significantly associated with 1-year adherence to statins (ACEI/ARB users: OR = 1.75, 95% CI = 1.37-2.25; OAD users: OR = 2.02, 95% CI = 1.46-2.79; concomitant ACEI/ARB and OAD users: OR = 1.73, 95% CI = 1.16-2.58). CONCLUSIONS: Past adherence to baseline medications may predict future adherence to newly initiated statins. Identifying patients likely to become nonadherent during treatment initiation could enable health care providers in recognizing individuals at risk of nonadherence and intervene earlier to enhance future adherence. DISCLOSURES: No funding was received for this study. Abughosh reports grants from Regeneron-Sanofi, BMS-Pfizer, and Valeant, unrelated to this work. Majd, Mohan, and Paranjpe have nothing to disclose.