Impact of COVID-19 measures on exacerbation rates and healthcare visits in US asthma patients.

Objective: To compare exacerbation rates and healthcare resource utilization (HCRU) in real-world patients in the United States who had moderate-to-severe asthma on medium- or high-dose inhaled corticosteroid/long-acting β₂-agonist therapy at different stages before and after the pandemic. Methods: This noninterventional, retrospective study described demographics, exacerbations, HCRU, and medication use in patients from a US-wide healthcare claims database in 4 consecutive years anchored around March 15, 2020 (start date of the first emergency health measures against coronavirus disease 2019 [COVID-19], or the first lockdown, in the United States, termed "restriction onset" hereafter). Four cohorts of patients potentially eligible for moderate-to-severe asthma clinical trials at the beginning (index) of each of four 1-year periods (March 15, 2018, 2019, 2020, 2021, respectively) were built. Exacerbations, healthcare visits, and asthma medication use were counted in the 1-year period after the index for each cohort. Results: The prevalence of patients with one or more exacerbation per year decreased by 10.00% in the first year after the restriction onset compared with the year before and attenuated over time to 6.37% in the second year. The proportion of inpatient, emergency department, and physician's office visits remained stable over the time periods evaluated for all patients and those patients who experienced one or more exacerbations. Asthma treatment of patients who experienced one or more exacerbations also remained stable over the 4 years. Conclusion: The effect of COVID-19 public health measures on asthma exacerbation rates might have affected clinical trials being run during this period and should be considered in their analysis. Asthma clinical trials run under pandemic hygiene restrictions should consider lower exacerbation frequency in their study design, while treatment and healthcare visits seem unchanged.