Geographic variation in disease burden among patients with severe persistent asthma in the United States

In the United States, a few studies have evaluated geographic variation of severe asthma at the subnational level.

To assess state-level geographic variation in the prevalence and characteristics of severe persistent asthma in the United States.

Patients aged above or equal to 12 years with severe persistent asthma were identified using nationally representative data from IQVIA open-source Medical/Pharmacy Claims and PharMetrics Plus databases (January 2019-December 2020). The index date was defined as the patient's earliest qualifying date for a severe asthma diagnosis. Baseline characteristics were measured during the 12-month pre-index period. Outcomes including exacerbation occurrence, asthma control, and medication use were measured during the 12-month post-index period and compared across states using census-level projections.

A total of 2,092,799 patients with asthma were identified; 496,750 (23.7%) met criteria for severe persistent asthma and all inclusion criteria. Mean age was 50.5 years; 68.4% were females. The prevalence of severe persistent asthma varied across states, ranging from 19.6% (New Mexico) to 31.9% (Alaska). Among patients with severe persistent asthma, 40.9% had more than or equal to 1 exacerbation, ranging from 34.2% (Vermont) to 45.6% (Louisiana); 21.1% had uncontrolled disease, ranging from 16.5% (Vermont) to 24.0% (Arizona). Among patients with exacerbations, 13.7% had exacerbation-related emergency department visits or hospitalizations, ranging from 7.0% (North Carolina) to 17.7% (Nevada). Among patients with severe uncontrolled asthma, 15.6% used biologics post-index, ranging from 2.2% (Hawaii) to 27.9% (Mississippi).

There is significant variability in severe persistent asthma prevalence and disease burden across US states. Reasons for geographic variation may include differences in socioeconomic/environmental factors or asthma management.