Association of Part D coverage gap with COPD medication adherence

Area of Science:

• Health Services Research
• Pharmaceutical Policy
• Pulmonology

Background:

• The Medicare Part D coverage gap, often called the "donut hole," can impact medication access and adherence for beneficiaries.
• Chronic obstructive pulmonary disease (COPD) is a progressive lung disease requiring consistent medication management.

Purpose of the Study:

• To evaluate the association between the Medicare Part D coverage gap and medication adherence in patients with COPD.
• To provide evidence for policy decisions regarding the elimination of the Part D coverage gap.

Main Methods:

• Retrospective analysis of Medicare claims data (2006-2010) for beneficiaries with COPD using long-acting bronchodilators (LABDs).
• Matched exposure (at risk of coverage gap) and control cohorts using high-dimensional propensity scores.
• Logistic regression analysis to determine the impact of the coverage gap on LABD adherence (defined as proportion of days covered ≥80%).

Main Results:

• In the matched cohorts (4147 patient-year observations each), approximately 17% of the exposure group encountered the coverage gap.
• Beneficiaries experiencing the Part D coverage gap showed a significantly lower likelihood of adherence to LABDs (OR, 0.603; 95% CI, 0.493-0.738).

Conclusions:

• The Medicare Part D coverage gap is linked to decreased medication adherence in COPD patients.
• These findings support policy initiatives to phase out the Part D coverage gap to improve patient outcomes.