Long-Term Impacts of COVID-19 on Severe Exacerbation and Mortality in Adult Asthma: A Nationwide Population-Based Cohort Study

Background: In adults with asthma, the long-term impact of previous coronavirus disease 2019 (COVID-19) on severe exacerbations and mortality is unclear. Objective: We evaluated the long-term risk of severe exacerbation and mortality in adults with asthma who recovered from COVID-19. Methods: Using the Korean National Health Insurance claim-based database, we compared the risk of severe exacerbations (emergency room visits or hospitalization) and mortality in adults with asthma aged greater than 20 years who had recovered from COVID-19 between October 8, 2020, and December 16, 2021 (COVID-19 cohort, n = 10,739) with 1:1 propensity score-matched controls (n = 10,739). Results: During a median follow-up of 87 days (range, 15-448 days), the incidence rate of severe exacerbations in the COVID-19 cohort and the matched cohort was 187.3 and 119.3 per 10,000 person-years, respectively. The COVID-19 cohort had a higher risk of severe exacerbation compared with the matched cohort (hazard ratio = 1.57; 95% CI, 1.06-2.32). During a median follow-up of 360 days (range, 15-721 days), the incidence rate of death in the COVID-19 and matched cohorts was 128.3 and 73.5 per 10,000 person-years, respectively. The COVID-19 cohort had a higher risk of death (hazard ratio = 1.76; 95% CI, 1.33-2.30) compared with the matched cohort. When further analyzed by COVID-19 severity, severe COVID-19 was associated with a 5.12-fold (95% CI, 3.27-8.01) and 7.31-fold (95% CI, 5.41-9.88) increased risk of severe exacerbation and death, respectively, but non-severe COVID-19 was not. Conclusions: Our study shows that severe COVID-19 is associated with an increased long-term risk of severe exacerbation and mortality among individuals with asthma.