Asthma Medication Adherence and Utilization in Medicare-Enrolled Older Adults before and during COVID-19: An Observational Analysis of a Medication Therapy Management Cohort

ABSTRACT

Introduction: Medication adherence and prescribing among Medication Therapy Management (MTM)-eligible older adults with asthma have not been well studied. Research Question or Hypothesis: Was adherence among older adults affected by the COVID-19 pandemic? What patient characteristics and medications are associated with adherence and asthma exacerbations? Study Design: Retrospective observational cohort. Methods: MTM-eligible older patients with asthma diagnoses were included. Patients with chronic obstructive pulmonary disease were excluded. Proportion of days covered (PDC) determined adherence. High adherence was defined as PDC ≥80%. Medication adherence during January-July 2019 and January-July 2020 was compared. Conditional logistic regression assessed relationships between characteristics and medication use with high adherence to inhaled corticosteroids (ICS) and asthma exacerbations. Results: Total of 2320 patients studied;497 were with moderate and 156 with severe asthma. In 2019, proportions were low of patients with high adherence to controller medications with moderate (38-54%) and severe asthma (46-63%). In 2020, proportions remained low of patients with high adherence with moderate (30-49%) and severe asthma (46-65%). High adherence was associated with higher number of prescribers (Odds Ratio (OR) 1.4-1.75, p ≥0.04), increasing days-supply of systemic corticosteroids (OR 1.33-1.44, p ≥0.03), long-acting-beta-agonists (LABA) use (OR 1.65, p<0.001) and montelukast (OR 1.25, p=0.04). Among patients with moderate and severe asthma, high adherence to ICS was associated with asthma exacerbations and LABA use. In this same cohort, exacerbations were associated with increasing short-acting-beta-agonists (SABA) dispenses (OR 1.62-2.47, p ≥0.02) and albuterol nebulizer use (OR 2.25, p<0.001). Conclusion: Asthma medication adherence among older adults with moderate and severe asthma was alarmingly low in 2019 and remained low during the COVID-19 pandemic in 2020. Asthma exacerbations among these patients were associated with SABA fills and albuterol nebulizers. MTM programs can electronically identify suboptimal medication use by utilizing these findings to improve outcomes among patients with asthma.