Abstract P366: Enrollment in Medicare Managed Care Plan is Associated With Higher Adherence to Anti-Hypertensive Drugs

Introduction: Adherence to anti-hypertensive drugs, which is sub-optimal despite public health and policy efforts, is essential in controlling high blood pressure. Medicare Advantage plans are gaining popularity, partly due to their managed care designs that held promise to improve chronic disease management. Hypothesis: We assessed the hypothesis that hypertensive patients with a managed care plan have higher adherence to antihypertensive drugs than those with a non-managed care plan. Methods: We analyzed medication adherence – measured using proportion of days covered (PDC) over 12 months for antihypertensive drugs – among 174,172 patients with a hypertension diagnosis from the medical and pharmacy claims and benefits data in the 2017-2019 IBM MarketScan Research Database. We fitted separate generalized linear regression models among monotherapy (use of one class of antihypertensive drugs) and polytherapy (combined use of at least two classes of antihypertensive drugs) users and computed postestimation margins with the best-fitted model to compare medication adherence by plan type: 1) Managed Care exclusive provider organization and health management organization (EPO/HMO) plan, 2) Managed Care point-of-service plan, 3) Managed Care preferred provider organization plan, 4) non-Managed Care comprehensive plan, 5) non-Managed Care consumer driven health plan / high deductible health plan. Other patient characteristics included in the analyses were age, age-squared, sex, comorbidities, census region, and their interaction terms. Results: The average PDC among Medicare patients on monotherapy was 0.53 and among those on polytherapy was 0.74. Patients with a managed-care EPO/HMO plan had the highest PDC (0.53, 95% confidence interval [CI]: 0.52, 0.54 among monotherapy users and 0.73, 95% CI: 0.72, 0.74 among polytherapy users, respectively) and those with a non-managed care comprehensive plan had the lowest PDC (0.42, 95% CI: 0.41, 0.43 among monotherapy users and 0.62, 95% CI: 0.61, 0.63 among polytherapy users, respectively). By census region, patients living in the North Central region with a managed care EPO/HMO plan had the highest average PDC (0.71, 95% CI: 0.70, 0.72 among monotherapy users and 0.85, 95% CI: 0.84, 0.86 among polytherapy users, respectively). Other factors such as age, sex, and number of chronic conditions were significantly associated with PDC. Conclusions: In conclusion, with an increase in the proportion of older adults enrolled in Medicare Advantage insurance, managed care models may play a more important role in influencing adherence to essential drugs such as anti-hypertensive drugs among Medicare beneficiaries. Future research should investigate factors that promote adherence to medications across different managed care plan designs.