Medication adherence in Medicare-enrolled older adults with asthma and chronic obstructive pulmonary disease before and during COVID-19 pandemic.

Background: Medication adherence in Medicare-enrolled older adults with asthma and chronic obstructive pulmonary disease (COPD) before and during the coronavirus disease 2019 (COVID-19) pandemic is unknown.

Objectives: To evaluate medication adherence and determinants of high adherence before and during the COVID-19 pandemic in this population.

Design: Retrospective cohort study.

Methods: The proportion of days covered (PDC) reflected medication adherence from January to July 2019 and from January to July 2020. Patients <65 years of age, with COPD or asthma alone, or with cystic fibrosis were excluded. Paired t tests were used to assess adherence changes. Logistic regression explored association of age, sex, diagnosis of depression, number of medications, medication-related problems, prescribers, pharmacies, controller medication classes, albuterol rescue inhaler fills, oral corticosteroid fills, and having a 90-day supply with high adherence (PDC ⩾ 80%).

Results: This analysis included 989 patients. In this cohort, 61.2% of patients received oral corticosteroids. Over 60% of patients had ⩾3 rescue fills in both 2019 and 2020. Medication adherence to controller medications significantly decreased for all controller medications (p < 0.001) in 2020. In 2019 and 2020, number of controller medication classes and having a 90-day supply were associated with high adherence (p < 0.001). In 2019, variables associated with high adherence also included number of medication-related problems and having ⩾3 albuterol rescue inhalers (p < 0.001).

Conclusion: Medication adherence to controllers significantly decreased during the pandemic among older adults with asthma and COPD. Patients with multiple controller classes and a 90-day supply were more likely to be highly adherent. A 90-day supply of medications should be used to facilitate access to medication during the pandemic. Healthcare professionals should assess medication adherence, resolve the barriers of adherence and medication-related problems to achieve desired clinical outcomes among older adults with both asthma and COPD.