Association between the Part D coverage gap and adverse health outcomes

Abstract

Objectives: To determine whether Part D coverage gap entry is associated with risk of death or hospitalization for cardiovascular outcomes.

Design: Prospective cohort study. Beneficiaries entered the study upon reaching the coverage gap spending threshold and were observed until an outcome reaching the threshold for catastrophic coverage occurred or year's end. Nine thousand four hundred thirty-six exposed individuals (those who were responsible for drug costs in the gap) were compared with 9,436 unexposed individuals (those who received financial assistance) based on propensity score (PS) or high-dimensional propensity score (hdPS).

Setting: Medicare Part D drug insurance.

Participants: Three hundred three thousand nine hundred seventy-eight Medicare beneficiaries aged 65 and older in 2006 and 2007 with linked prescription and medical claims who enrolled in stand-alone Part D or retiree drug plans and reached the gap spending threshold.

Measurements: Rates of death and hospitalization for any of five cardiovascular outcomes, including acute coronary syndrome with revascularization (ACS), after reaching the coverage gap spending threshold were compared using Cox proportional hazards models.

Results: In PS-matched analyses, exposed beneficiaries had higher, albeit not significantly so, hazard of death (hazard ratio (HR) = 1.25, 95% confidence interval (CI) = 0.98-1.59) and ACS (HR = 1.16, 95% CI = 0.83-1.62) than unexposed beneficiaries. hdPS-matched analyses minimized residual confounding and confirmed results (death: HR = 0.99, 95% CI = 0.78-1.24; ACS: HR = 1.07, 95% CI = 0.81-1.41). Exposed beneficiaries were no more or less likely to experience other outcomes than were those who were unexposed.

Conclusion: During the short-term coverage gap period, having no financial assistance to pay for drugs was not associated with greater risk of death or hospitalization for cardiovascular causes, although long-term health consequences remain unclear.