Associations between chronic disease, polypharmacy, and medication-related problems among medicare beneficiaries

Abstract

BACKGROUND: Mismanaged polypharmacy among older adults costs the health care system approximately $2 billion each year. Medication therapy management (MTM), a service designed to optimize medication use, improve health outcomes, and reduce associated costs, is available to eligible Medicare beneficiaries. Yet, it remains unclear which beneficiaries benefit most from this service. OBJECTIVE: To assess associations between patient characteristics, chronic disease, polypharmacy, and medication-related problems (MRPs) in a sample population of Medicare beneficiaries. METHODS: This study was a retrospective cross-sectional analysis of 1 Medicare Part D plan provider for the year 2015. Medicare beneficiaries were included if they were eligible to receive MTM services and excluded if they were aged under 65 years or the dataset had no count of MRPs for the beneficiary. A negative binomial regression assessed the relationship between age, sex, and chronic health conditions with MRPs. Second and third negative binomial regressions assessed the relationship between age, sex, and polypharmacy with MRPs. RESULTS: A sample of 27,765 Medicare beneficiaries had a mean (SD) age of 76 (±7) years, were predominantly female (59%), and used a mean (SD) of 11 (±4) chronic medications. Beneficiaries with certain conditions were more likely to incur an MRP than those without, including depression (OR=1.58; 95% CI=1.51-1.64), congestive heart failure (OR=1.26; 95% CI=1.20-1.31), diabetes (OR=1.24; 95% CI=1.18-1.29), end-stage renal disease (OR=1.38; 95% CI=1.25-1.52), respiratory conditions (OR=1.25; 95% CI=1.19-1.31), and hypertension (OR=1.09; 95% CI=1.01-1.18). Medicare beneficiaries with polypharmacy (11 or more medications) were 1.86 (95% CI=1.80-1.93) times more likely to experience an MRP than those taking fewer medications. For every additional medication, the odds of incurring an MRP increased by 10% (OR=1.11; 95% CI=1.10-1.1.11). CONCLUSIONS: The diagnosis of depression presented with the strongest association with MRPs. Diabetes, congestive heart failure, end-stage renal disease, respiratory conditions, and hypertension also presented with significant associations with MRPs. Beneficiaries with polypharmacy (11 or more medications) were almost 2 times more likely to experience an MRP than those taking fewer medications. Addition of a chronic medication resulted in a 10% increase in the odds of incurring an MRP. MTM programs may find a greater number of MRPs among those diagnosed with depression in their MTM-eligible patient populations.