Recovery of kidney function after AKI because of COVID-19 in kidney transplant recipients

Evidence on the evolution of graft function in kidney transplant recipients recovering from coronavirus disease-2019 (COVID-19) is lacking. This multicenter observational study evaluated the short-term clinical outcomes in recipients with acute kidney injury (AKI) secondary to COVID-19. Out of 452 recipients following up at five centers, 50 had AKI secondary to COVID-19. 42 recipients with at least 3-month follow-up were included. Median follow-up was 5.23 months [IQR 4.09-6.99]. Severe COVID-19 was seen in 21 (50%), and 12 (28.6%) had KDIGO stage 3 AKI. Complete recovery of graft function at 3 months was seen in 17 (40.5%) patients. Worsening of proteinuria was seen in 15 (37.5%) patients, and 4 (9.5%) patients had new onset proteinuria. Graft failure was seen in 6 (14.3%) patients. Kidney biopsy revealed acute tubular injury (9/11 patients), thrombotic microangiopathy (2/11), acute cellular rejection (2/11), and chronic active antibody-mediated rejection (3/11). Patients with incomplete recovery were likely to have lower eGFR and proteinuria at baseline, historical allograft rejection, higher admission SOFA score, orthostatic hypotension, and KDIGO stage 3 AKI. Baseline proteinuria and the presence of orthostatic hypotension independently predicted incomplete graft recovery. This shows that graft recovery may remain incomplete after AKI secondary to COVID-19.