Risks of infection and severity of coronavirus disease 2019 in kidney transplant recipients: A single-center cohort study

Background The severity of coronavirus disease 2019 (COVID-19) is known to be high in kidney transplant recipients; however, the risk factors for COVID-19 infection in these patients has not been studied extensively. Therefore, we explored the predictors of COVID-19 infection and severity in kidney transplant recipients in Japan. Methods This study included kidney transplant recipients who were regularly followed-up at our hospital from February 2021 to March 2023. We retrospectively reviewed the patients' medical charts; obtained their clinical information, including comorbidities, immunosuppressant usage, and presence of COVID-19 infection; and assessed the risk of COVID-19 infection and severity. Severe illness was defined as a decrease in oxygen saturation. Results Among the 155 patients, 50 (32.3%) were infected with COVID-19. Multivariate analysis revealed that recipients taking >5 mg of prednisolone or taking tacrolimus instead of cyclosporine were at higher risk of infection (odds ratio [OR] 2.34, 95% confidence interval [CI] 1.01–5.40; OR 2.29, 95% CI 1.03–5.07, respectively). Furthermore, of the 50 infected recipients, 42 had minor illness and eight had severe illness. Multivariate analysis revealed that recipients taking >5 mg of prednisolone were at a higher risk of severity (OR, 11.60, 95% CI 1.19–113.00). Conclusion In kidney transplant recipients, the infection rate and severity of COVID-19 tended to increase with higher maintenance doses of steroids. Recipients taking >5 mg of prednisolone should be considered a switch from tacrolimus to cyclosporine because cyclosporine may inhibit viral replication and reduce the risk of infection.