Community-Acquired Acute Kidney Injury and Late Kidney Dysfunction in Survivors of COVID-19 Hospitalization

Data on the incidence and risk factors for renal long COVID are scarce. We aimed to investigate 2 acute kidney injury (AKI) phenotypes, namely community-acquired (CA; CA-AKI) and hospital-acquired (HA; HA-AKI), and the development of late kidney dysfunction in survivors of COVID-19 hospitalization.

This is a prospective cohort study of survivors of moderate-to-severe COVID-19 hospitalization in Brazil, from March to August 2020. The patients were assessed for up to 11 months after hospital discharge. Exposure was CA-AKI and HA-AKI. The main outcome was kidney dysfunction defined as incident low estimated glomerular filtration rate (eGFR; < 60 ml/min per 1.73 m²) and/or eGFR decline ≥ 25% from discharge at follow-up. An adjusted binary logistic regression analysis was run.

A total of 655 survivors were evaluated (6.5 ± 1.9 follow-up months); 79% had AKI (35% CA and 43% HA); 14% used kidney replacement therapy (KRT). Late kidney dysfunction occurred in 28% of the patients (16% with incident low eGFR and 27% with eGFR decline ≥ 25%). CA-AKI, but not HA-AKI, was independently associated with late kidney dysfunction (adjusted odds ratio [aOR] = 7.3, 95% confidence interval (CI): 3.6-15.8 and aOR = 2.2, 95% CI: 0.9-4.8, respectively).

In conclusion, late kidney dysfunction affected 1 in 4 COVID-19 survivors. CA-AKI, but not HA-AKI, was an independent risk factor for late kidney dysfunction. These findings suggest that renal long COVID might be frequent and that a specific AKI phenotype (CA-AKI) may play a crucial role in its development. Our research highlights the need for CA-AKI prevention and for the long-term follow-up and care of patients affected by this AKI phenotype during COVID-19 infection.