Chronic Health Outcomes and Prescription Drug Copayments in Medicaid.

Abstract

Prescription drug copayments and cost-sharing have been linked to reductions in prescription drug use and expenditures. However, little is known about their effect on specific health outcomes. To evaluate the association between prescription drug copayments and uncontrolled hypertension, uncontrolled hypercholesterolemia, and prescription drug utilization among Medicaid beneficiaries with these conditions. Select adults aged 20-64 from NHANES 1999-2012 in 18 states. Uncontrolled hypertension, uncontrolled hypercholesterolemia, and taking medication for each of these conditions. A differencing regression model was used to evaluate health outcomes among Medicaid beneficiaries in 4 states that introduced copayments during the study period, relative to 2 comparison groups-Medicaid beneficiaries in 14 states unaffected by shifts in copayment policy, and a within-state counterfactual group of low-income adults not on Medicaid, while controlling for individual demographic factors and unobserved state-level characteristics. Although uncontrolled hypertension and hypercholesterolemia declined among all low-income persons during the study period, the trend was less pronounced in Medicaid beneficiaries affected by copayments. After netting out concurrent trends in health outcomes of low-income persons unaffected by Medicaid copayment changes, we estimated that introduction of drug copayments in Medicaid was associated with an average rise in uncontrolled hypertension and uncontrolled hypercholesterolemia of 7.7 and 13.2 percentage points, respectively, and with reduced drug utilization for hypercholesterolemia. As Medicaid programs change in the years following the Affordable Care Act, prescription drug copayments may play a role as a lever for controlling hypertension and hypercholesterolemia at the population level.