Abstract
PURPOSE: Population-based studies provide conflicting evidence about how inhaled corticosteroids (ICS) impact COVID-19 outcomes among COPD patients. We investigated whether regular ICS exposure affects risk, severity, or survival in SARS-CoV-2 infection, using a nationwide linked Swedish population register database. PATIENTS AND METHODS: During January-December 2020, we studied two defined Swedish adult populations - Whole population [≥40 years] (N = 5243479), and COPD subpopulation [≥40 years] (N = 133372), in three study cohorts, respectively: 1. Overall cohort (index date 1 Jan 2020), 2. COVID-19 diagnosed sub-cohort (index date = diagnosis date), and 3. COVID-19 hospitalized sub-cohort (index date = admission date). Regular exposure was defined as ≥3 ICS prescriptions in the year before index. Hazard ratios (HRs) for outcomes (COVID-19 onset, hospitalization, ICU admission, or death) related to ICS exposure were estimated using Cox regression. Confounding was controlled by propensity score methods applying Average Treatment effect in the Treated (ATT) weighting. RESULTS: Regular ICS use was associated with only very slightly increased onset of COVID-19, hospitalization, ICU admission, and death in the overall whole population cohort and in the overall COPD subpopulation cohort, except for ICU admission (marginally non-significant HRs, up to 1.13); and no clear increase in the diagnosed sub-cohorts. However, in the COVID-19 hospitalized COPD sub-cohort, ICS therapy showed reduced risks against progression to ICU admission and death, significant for death (HR 0.82 95% CI [0.67-0.99]). CONCLUSION: For COPD patients, ICS therapy offers some protection against progression to ICU admission and death among COVID-19 hospitalized patients. Our findings alleviate concerns about increased risks of COVID-19 by ICS treatment and provide evidence supporting the continuation of ICS therapy for COPD patients.