Exacerbations in US Severe Asthma: Incidence, Characteristics, Predictors, and Effects of Biologic Treatments.

Abstract

BACKGROUND\nPatients with severe asthma (SA) have a heightened risk of exacerbations, including hospitalization. The real-world, specialist-verified incidence and characteristics of exacerbations among patients with SA in the United States (US) have not been described.\n\n\nOBJECTIVE\nTo describe the real-world incidence, characteristics, and predictors of exacerbations among patients with SA in the US.\n\n\nMETHODS\nCHRONICLE is an ongoing observational study of specialist-treated US adults with SA receiving biologic treatment or maintenance systemic corticosteroids (SCS), or uncontrolled by high-dosage inhaled corticosteroids with additional controllers. For patients enrolled February 2018 to February 2020, annualized rates and characteristics of exacerbation-related events were summarized by treatment category for 12 months before enrollment and after enrollment through the latest data collection. Results were further analyzed for subgroups of interest.\n\n\nRESULTS\nAmong 1884 enrolled patients, 53.5% and 12.3% experienced an exacerbation and asthma hospitalization, respectively (0.81 and 0.14 per person-year). Of all exacerbations, 36%, 9%, and 15% required an unscheduled healthcare provider visit, emergency department visit without hospitalization, and hospitalization, respectively. Among patients not receiving biologics or SCS, higher blood eosinophil count, higher fractional exhaled nitric oxide, and lower total immunoglobulin E level were associated with higher exacerbation rates. Exacerbation rates decreased after starting or switching biologics (n\u202f=\u202f1299). Multivariate analyses of enrolled patients showed prior-year exacerbations/hospitalizations, lack of asthma control, and geographic region also predicted event risk.\n\n\nCONCLUSION\nIn this real-world cohort of specialist-treated US adults with SA, there was a substantial burden of exacerbations and associated healthcare resource utilization. Patients receiving biologics had a lower exacerbation burden.