Medication Adherence and Subsequent Year Payer Medical Costs Among Medicare Advantage Beneficiaries: Differences across Quality Measures

Author(s)

Parikh M1, Nsiah I2, Campbell P3, Ramachandran S4, Karmarkar T5, Castora-Brinkley M6, Black H5, Bentley J4
1Pharmacy Quality Alliance, Kendall Park, NJ, USA, 2Department of Pharmacy Administration, School of Pharmacy, University of Mississippi, University, MS, USA, 3Merck & Co., Inc., North Wales, PA, USA, 4Department of Pharmacy Administration and Center for Pharmaceutical Marketing and Management, School of Pharmacy, University of Mississippi, University, MS, USA, 5Merck & Co., Inc., Rahway, NJ, USA, 6Pharmacy Quality Alliance, Alexandria, VA, USA

Presentation Documents

OBJECTIVES: To assess differences in the relationship between medication adherence and healthcare costs across three quality measures in a Medicare Advantage (MA) sample.

METHODS: An observational study was conducted among cohorts of MA beneficiaries using the 2018-19 Optum Clinformatics Data Mart. Pharmacy Quality Alliance’s adherence measures for 1) oral antidiabetics; 2) RASAs; and 3) statins were used to determine cohort eligibility. Cohort assignment was based on mutually exclusive inclusion in one of the adherence measures or inclusion in all three measures. Medication adherence, assessed as Proportion of Days Covered (PDC), was measured in year 1 and payer medical costs were measured in year 2. Generalized linear modeling (log link) with interaction terms was used to assess relationships between adherence and subsequent payer medical costs, and to evaluate differences in this relationship across the three measures. Separate analyses were conducted using Poisson and Gamma distributions. Analyses were adjusted for sociodemographic, clinical, prescription-related, and insurance-related variables.

RESULTS: The study cohort included 962,480 MA beneficiaries, with 272,371 beneficiaries included in all three PDC measures. There was a negative relationship (p<0.0001) between adherence in year 1 and payer medical costs in year 2 for all medication classes. These associations were stronger for diabetes medications, followed by RASA and statin medications. The findings were consistent for patients included in one of the three medication adherence cohorts and patients using all three medication classes. Additionally, results were consistent when comparing Gamma and Poisson models.

CONCLUSIONS: Better adherence was associated with lower payer medical costs across several therapeutic areas, providing additional evidence of the importance of adherence in managing health care costs. The relationship between adherence and future medical costs appears stronger for oral anti-diabetic medications relative to RASAs or statins. Further research may explore interventions to increase adherence to oral anti-diabetic medication to improve diabetes management.