Background: There is uncertainty of the effect of immunosuppression, including corticosteroids, before COVID-19 infection on COVID-19 outcomes. The aim of this study was to investigate the relationship between prehospitalization immunosuppressants use (exposure) and COVID-19 patient outcomes.
Methods: We conducted a population-based retrospective cohort study using a nationwide healthcare claims database of South Korea as of May 15, 2020. Confirmed COVID-19 infection in hospitalized individuals aged 40 years or older were included for analysis. We defined exposure variable by using inpatient and outpatient prescription records of immunosuppressants from the database. Our primary endpoint was a composite endpoint of all-cause death, intensive care unit (ICU) admission, and mechanical ventilation use. Inverse probability of treatment weighting (IPTW)-adjusted logistic regression analyses were used, to estimate odds ratio (OR) and 95% confidence intervals (CI), comparing immunosuppressants users and non-users.
Results: We identified 4,349 patients, for which 1,356 were immunosuppressants users and 2,993 were non-users. Patients who used immunosuppressants were at increased odds of the primary endpoint of all-cause death, ICU admission and mechanical ventilation use (IPTW OR =1.32; 95% CI: 1.06-1.63), driven by higher odds of all-cause mortality (IPTW OR =1.63; 95% CI: 1.21-2.26). Patients who used corticosteroids (n=1,340) were at increased odds of the primary endpoint (IPTW OR =1.33; 95% CI: 1.07-1.64).
Conclusions: Immunosuppressant use was associated with worse outcomes among COVID-19 patients. These findings support the latest guidelines from the CDC that people on immunosuppressants are at high risk of severe COVID-19 and that immunocompromised people may benefit from booster COVID-19 vaccinations.
Keywords: COVID-19; Immunosuppressants.