Pattern and Adherence to Maintenance Medication Use in Medicare Beneficiaries with Chronic Obstructive Pulmonary Disease: 2008-2013.

Background: Maintenance medications provide symptomatic relief, improve lung function and reduce the risk of exacerbations in patients with chronic obstructive pulmonary disease (COPD). Despite their proven benefits, limited information exists on maintenance medication use and adherence among users. Objective: We examined the patterns and factors associated with the receipt of and adherence to maintenance medication in individuals with COPD. Methods: A retrospective cross-sectional study of 5% of Medicare beneficiaries enrolled in Parts A, B and D with COPD who received maintenance medication from 2008 to 2013 was conducted. Maintenance medication includes: inhaled corticosteroids (ICSs), long-acting beta2- agonists (LABAs) and long-acting muscarinic antagonists (LAMAs) alone or in combination. We examined the proportion of beneficiaries with COPD who had at least one prescription filled for maintenance medication. Among users of maintenance medications, we also examined adherence, defined as proportion of days covered (PDC) ≥80% over the year from the first maintenance medication prescription fill date. Results: Overall, maintenance medication (LAMAs, LABAs, ICSs and/or LABA/ICS) use increased from 67.8% in 2008 to 72.1% in 2013. The increase is related to increases in use of LABA/ICS, which rose from 41.1% in 2008 to 49.6% in 2013. Factors associated with receipt of maintenance medication include female gender, recent COPD hospitalization (odds ratio [OR] 1.63; 95% confidence interval [CI] 1.54-1.73), oxygen therapy (OR 1.74 95% CI, 1.68-1.81), dual eligibility status (OR 1.45; 95% CI 1.39-1.51), higher education level and evaluation by a pulmonary provider (OR 1.88; 95% CI 1.81-1.96). The overall adherence among maintenance medication users remained flat. The most important factor associated with adherence was dual eligibility status (OR, 1.67; 95% CI: 1.59-1.75). Conclusions: Receipt of maintenance medications increased during the study period and was higher in those with dual eligibility. Overall, adherence to maintenance medications was suboptimal and remained unchanged.