Association between Difficulty Affording Medications and Outcomes in Chronic Obstructive Pulmonary Disease

Rationale: Medications, including inhaled bronchodilators, are essential for effective management of chronic obstructive pulmonary disease (COPD) and to improve clinical outcomes. However, medications are a major driver of out-of-pocket costs for individuals with COPD. The impact of cost of medications on clinical outcomes in COPD has not been studied. Objectives: To examine the association between difficulty affording medications and COPD morbidity, psychological well-being, and medication adherence. Methods: Individuals with a physician's diagnosis of COPD who were prescribed at least one daily maintenance medication were recruited from centers in the Mid-Atlantic area and followed for 12 months as part of the Medication Adherence Research in COPD (MARC) cohort. Patient-reported COPD outcomes, measures of psychological well-being, exacerbation data, and difficulty affording medications were assessed at 6-month intervals. Medication adherence was measured during the 12-month period using electronic monitors. The association between difficulty affording medications at baseline and outcomes at 12 months was evaluated using multivariable regression models. A fixed effects regression model was conducted to evaluate how changes in difficulty affording medications are associated with outcomes over time. Results: Of the 249 participants with completed baseline assessments, a total of 44 (18%) participants reported delaying refilling medications because of cost at baseline. Over the course of the 12-month period, 68 (27%) participants reported delaying refilling medications at any time point because of cost. After adjusting for baseline covariates, no associations between difficulty affording medications at baseline and outcomes at 12 months were observed. In the fixed effects model, changes in difficulty affording medications were associated with worse COPD health status, dyspnea, and health-related quality of life; increased symptoms of anxiety and depression; and lower objectively measured medication adherence but not occurrence of exacerbations. Conclusions: In this multicenter cohort of individuals with physician-diagnosed COPD, we found an association between changes in self-reported difficulty affording medications and increased patient-reported respiratory morbidity, increased anxiety and depression symptoms, and decreased objectively measured medication adherence over time, but no association with exacerbations. These findings suggest that cost of COPD-specific treatments is an important and potentially modifiable social determinant of health for individuals with COPD.