Immunosuppressed patients with COVID-19 pneumonia in ICU: clinical characteristics and factors influencing outcomes

Abstract
Introduction COVID-19 severely impacted global health, especially older adults and those with comorbidities. Immunosuppressed patients are at high risk for severe outcomes, yet studies yield conflicting mortality rates for this group. This study examines the clinical characteristics and outcomes of immunosuppressed (IS) versus nonimmunosuppressed
(nIS) patients with COVID-19 in ICUs.
Methods A multicenter, observational case–control study included 5,824 ICU patients with COVID-19 from the CIBERESUCICOVID study. Patients were categorized as IS or nIS based on history of transplantation, HIV, active neoplasia, and use of immunosuppressive drugs or corticosteroids. The primary outcome was 90-day mortality; secondary outcomes included in-hospital, 15-day, 30-day and 1-year mortality, ICU-free days, ventilator-free days, and hospital length of stay. Subgroup analyses examined vaccination status and tocilizumab treatment. Propensity score (PS) matching was used to obtain balance among the baseline variables in the two groups.
Results IS patients (n = 689, 11.8%) were older, had more comorbidities, and higher APACHE-II scores. After PS matching, IS patients had higher 90-day mortality (39 vs. 33%; HR 1.30, 95% CI 1.04 to 1.62), as well as higher in-hospital (37 vs. 29%; sHR 1.35, 95% CI 1.08 to 1.69), 30-day (28 vs 23%; HR 1.31, 95% CI 1.01 to 1.69) and 1-year mortality (45 vs. 38%; HR 1.26, 95% CI 1.02 to 1.57). Among IS patients, transplant recipients had significantly higher 90-day mortality after matching (HR 4.45, 95% CI 1.46 to 13.58). Vaccinated IS patients showed higher mortality than vaccinated nIS patients, though differences were not significant after PS matching. Tocilizumab treatment in IS patients was associated with reduced mortality; multivariable analysis confirmed a significant decrease in in-hospital mortality (sHR 0.56, 95% CI 0.42 to 0.76).
Conclusion Critical immunosuppressed patients with COVID-19 have higher mortality, particularly transplant recipients. Tocilizumab shows potential benefits for IS patients. These findings highlight the need for tailored therapeutic strategies for immunosuppressed individuals with severe COVID-19. Further research is needed to confirm these results in the current clinical context.