Adherence to inhaled corticosteroid medications after an asthma exacerbation and the risk of subsequent exacerbations.

Abstract

Background: Data on the duration of improved adherence to controller medications after an exacerbation and its impact on asthma outcomes are inconsistent.

Objective: To describe levels and changes in adherence to inhaled corticosteroid (ICS)-containing medication after a severe exacerbation and the association with future exacerbation risk.

Methods: This retrospective cohort study used data from Optum's deidentified Clinformatics Data Mart Database (October 2015-December 2023). Patients with asthma, 1 or more severe exacerbations, and adherence to ICS-containing therapy (proportion of days covered [PDC]) of less than 80% in the 3 months before an exacerbation were included. Primary and secondary end points were the annualized asthma exacerbation rate and the time to the first subsequent severe exacerbation. End points were compared between patients who improved adherence in the 3 months after the qualifying exacerbation to 80% or more and those who remained at PDC less than 80%. Inverse probability of treatment weighting accounted for between-group imbalances.

Results: Of 68,398 participants, 85% stayed less than 80% PDC, whereas 15% improved to PDC 80% or more at 3 months after the qualifying exacerbation. Of patients with improved PDC, only 40%, 31%, and 22% maintained PDC 80% or more at 3 to 6, 6 to 9, and 9 to 12 months after the qualifying exacerbation, respectively. Improving adherence to PDC 80% or more in the 3 months after the qualifying exacerbation did not reduce annualized asthma exacerbation rate (rate ratio: 0.958 [95% CI 0.912-1.007]) or increase the time to the next exacerbation (hazard ratio: 0.997 [95% CI 0.954-1.041]). Results were consistent in sensitivity analyses.

Conclusion: Improvement in adherence to ICS-containing therapy after a severe exacerbation was transient and not beneficial for exacerbation outcomes, indicating a need to consider alternative treatment strategies in patients with asthma.