Medication Adherence and Healthcare Disparities: Impact of Statin Co-Payment Reduction

Objectives: Minority patients have lower rates of cardiovascularmedication adherence, which may be amenable to co-payment reductions.Our objective was to evaluate the effect of race on adherencechanges following a statin co-payment reduction intervention.Study Design: Retrospective analysis.Methods: The intervention was implemented by a large selfinsuredemployer. Eligible individuals in the intervention cohort(n = 1961) were compared with a control group of employees ofother companies without such a policy (n = 37,320). As a proxy forrace, we categorized patients into tertiles based on the proportionof black residents living in their zip code of residence. Analyseswere performed using difference-in-differences design with generalizedestimating equations.Results: Prior to the new co-payment policy, adherence rateswere higher for individuals living in areas with fewer black residents.In multivariable models adjusting for demographic factors,clinical covariates and baseline trends, the co-payment reductionincreased adherence by 2.0% (P = .14), 2.1% (P = .15) and 6% (PStatistic