Predictors of severe COVID-19 in kidney transplant recipients in the different epidemic waves: Analysis of the Spanish Registry.

SARS-CoV-2 infection has produced high mortality in kidney transplant (KT) recipients, especially in the elderly. Until December 2020, 1011 KT with COVID-19 have been prospectively included in the Spanish Registry and followed until recovery or death. In multivariable analysis, age, pneumonia, and KT performed ≤6 months before COVID-19 were predictors of death, whereas gastrointestinal symptoms were protective. Survival analysis showed significant increasing mortality risk in four subgroups according to recipient age and time after KT (age <65 years and posttransplant time >6 months, age <65 and time ≤6, age ≥65 and time >6 and age ≥65 and time ≤6): mortality rates were, respectively, 11.3%, 24.5%, 35.4%, and 54.5% (p < .001). Patients were significantly younger, presented less pneumonia, and received less frequently specific anti-COVID-19 treatment in the second wave (July-December) than in the first one (March-June). Overall mortality was lower in the second wave (15.1 vs. 27.4%, p < .001) but similar in critical patients (66.7% vs. 58.1%, p = .29). The interaction between age and time post-KT should be considered when selecting recipients for transplantation in the COVID-19 pandemic. Advanced age and a recent KT should foster strict protective measures, including vaccination.