[Clinical characteristics of immunocompromised patients infected with COVID-19]

Objective: To analyze the clinical features of COVID-19 infection in hospitalized immunocompromised patients in comparison with immunocompetent patients. Methods: A single-center retrospective observational study was conducted on 213 inpatients diagnosed with COVID-19 in the Peking University People's Hospital between December 2022 and October 2023. They were divided into an immunocompromised group (102 patients, 47.9%) and an immunocompetent group(111 patients, 52.1%), and clinical data were compared between the two groups. The immunocompromised group was further divided into death group (18 cases, 17.6%) and non-death group (84 cases, 82.4%). The differences in laboratory examination findings were compared. Further analysis was performed on the lymphocyte subset differences between the death group(10 patients, 9.8%) and the non-death group (36 patients, 35.3%) with complete data. Results: The proportion of severe and critical cases and the mortality rate, were significantly higher in the immunocompromised group than the immunocompetent group (47.1% vs. 40.5%, 18.6% vs. 9.0%, 17.6% vs. 9.0%,P<0.05). The immunocompromised group had lower vaccination rate (26.5% vs. 44.1%, P<0.05). Hypertension, kidney disease and infections were more common in the immunocompromised group (63.7% vs. 48.6%, 30.4% vs. 9.0%, 49.0% vs. 19.8%, all P<0.05). CT findings of consolidation (40.2% vs. 18.9%), rate of antiviral treatment (48.0% vs. 30.6%) and the positive duration of viral nucleic acid [median 14(7.0, 19.3) days vs. 9(7.0, 18.0) days] were higher in the immunocomprised group (all P<0.05). Lactate dehydrogenase (LDH), procalcitonin (PCT), interleukin-6 (IL-6) and ferritin were higher in the immunocompromised group than those in the immunocompetent group (all P<0.05). In the death group, neutrophils (NEU), C-reactive protein (CRP), PCT, IL-6, ferritin and D-dimer were higher, while lymphocytes (LY), CD4⁺T-cells, CD8⁺T-cells, B-cell counts and hemoglobin (HGB) were significantly lower than those in the non-death group (all P<0.05). Conclusions: More than 60% of patients in the immunocompromised group were classified as severe or critical type, with a higher mortality rate and decreased ability to clear severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Decreases in total lymphocytes, CD4⁺T lymphocytes, CD8⁺T lymphocytes, and B lymphocytes, along with elevated levels of procalcitonin, ferritin, and D-dimer, indicated poor prognosis.