Long-Term Decline in Renal Allograft Function After Severe COVID-19 in Kidney Transplant Recipients: Evidence From a Four-Year Retrospective Cohort Study.

Background: While coronavirus disease (COVID-19) has been extensively studied, long-term follow-up data in kidney transplant recipients (KTRs), particularly concerning the impact of severe COVID-19 on graft function, remain limited. This study provides critical evidence of sustained renal injury in KTRs with severe COVID-19, focusing on acute kidney injury (AKI) as a predictor of accelerated graft dysfunction over a 4-year follow-up period.

Methods: We conducted a retrospective cohort study of 43 KTRs hospitalized with COVID-19 in Brazil (April 2020 and July 2024). The survivors were followed up for a median of 2.5 years (range: 1.2-4.2 years). Longitudinal graft function was assessed using estimated glomerular filtration rate (eGFR) trajectories modeled with linear mixed-effects analysis.

Results: The in-hospital mortality rate was 37.2%. AKI occurred in 65.1% of patients and was more frequent among nonsurvivors (87.5% vs 51.9%, P < .05). Of the 13 patients requiring kidney replacement therapy, only 2 survived. Among the 27 survivors, we observed a significant decline in eGFR from 47.99 to 40.57 mL/min/1.73 m² (P = .032) in the follow-up period, driven by a steeper annual decline in those with AKI (-6.99 mL/min/1.73 · m² per year vs stable eGFR in non-AKI patients, P = .049). By the final follow-up, AKI survivors had a significantly lower eGFR than non-AKI patients (12.58 vs 47.57 mL/min/1.73 m², P = .003).

Conclusion: Severe COVID-19 has a lasting impact on graft function in KTRs, particularly in those with AKI. These findings underscore the importance of long-term nephrological surveillance and individualized post-COVID-19 management strategies for slowing graft dysfunction progression in this high-risk population.