SARS-CoV-2 Omicron infection in a cohort of hospitalized kidney transplant recipients: Risk factors of severity.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron is a major coronavirus variant, which was prevalent in China at the end of 2022 and caused widespread infection. As an immunosuppressed group, renal transplant recipients with SARS-CoV-2 infection are prone to developing serious pneumonia or an adverse outcome event if the infection is not treated in time. Here, we analyze the possible risk factors of infection severity.

Materials and methods: 92 cases of moderate and severe SARS-CoV-2 infection after renal transplantation were collected. Statistical methods, including Fisher's tests, F test, Spearman relative values, and multi-parameter logistic regression models, were used to analyze the risk factors for severe SARS-CoV-2 infection in renal transplant recipients.

Results: 44 cases complicated with hypertension were observed in the study cohort, among whom 30 were severe (OR: 4.63, p < 0.001). Out of 51 male patients infected with Omicron, 30 male patients presented with severe SARS-CoV-2 (OR: 2.45, p = 0.039). In renal transplant patients, hypertension comorbidity was closely correlated with clinical presentation (R = 0.369, p < 0.001). Blood routine test, chemistries, and additional indices showed increased neutrophils and C-reactive protein in patients with severe disease compared with the moderate group according to one-way analysis of variance (p = 0.004), while CD3 (p = 0.02) and CD4 (p = 0.04) showed lower expressional levels. We also observed meaningful correlations between neutrophil levels and hypertension comorbidity (R = 0.222, p = 0.034) and between interleukin-6 (IL-6) levels and diabetes comorbidity (R = 0.315, p = 0.011), with IL-6 considered a key factor in the context of coronavirus disease.

Conclusion: Renal transplant recipients were generally susceptible to infection with the Omicron variant, with a more pronounced incidence of severe illness observed in the group with hypertension comorbidity.