Asthma and COVID-19 Outcomes: A Prospective Study in a Large Health Care Delivery System.

INTRODUCTION

Previous studies on the outcomes of asthma and COVID-19 have shown inconsistent results. This study aimed to elucidate the association between asthma and COVID-19 outcomes.

METHODS

We conducted a prospective study with a large health plan to compare the incidence of COVID-19 infection, hospitalization and ICU admission in a cohort of 41,282 patients with asthma and a 1:1 age-, sex-, and race-ethnicity-matched cohort without asthma across the following pandemic periods: pre-Delta (03/01/2020 to 05/31/2021), Delta (06/01/2021 to 12/31/2021), and Omicron (01/01/2022 to 08/13/2022). Demographic factors, comorbidities, COVID-19 test results, inpatient utilization, and COVID-19 vaccination status were collected from electronic health records.

RESULTS

Subjects with asthma were more likely than controls to undergo COVID-19 testing during the three pandemic periods and were less likely to test positive in the Omicron period (fully adjusted odds ratio=0.92; 95% CI=0.86-0.98; p=0.01). Relative to controls, patients with asthma had an increased risk of hospitalization for COVID-19 (fully adjusted hazard ratio=1.33; 95% CI=1.08-1.64; p=0.01) and borderline significant (p=0.05) higher rates of ICU admissions in the pre-delta period but not during the delta or Omicron periods. The increased risk of COVID-19 hospitalization associated with asthma was more pronounced in patients with severe asthma and in women compared with men. None of the associations were significantly modified by vaccination status.

CONCLUSION

Asthma was associated with a lower risk of COVID-19 infection but only during the Omicron period. Asthma was an independent risk factor for hospitalization for COVID-19 in the pre-delta period and this association was stronger for severe asthma and in women.