Long-Term Kidney Function of COVID-19 Survivors: A Prospective Cohort Study

Background: Long COVID encompasses symptoms that persist >2 months. Its effects on kidney function remain poorly understood. We aimed to investigate the long-term kidney function of COVID-19 survivors. Methods: A prospective cohort of moderate and severe COVID-19 surviving patients was analyzed. Eligible patients were contacted at 6–9 months after hospital discharge. Kidney function at hospital admission, discharge, and follow-up was assessed by estimated glomerular filtration rate (eGFR; CKD-EPI serum creatinine race-free equation). Urinary albumin was evaluated at follow-up. Major Adverse Kidney Events (MAKE) at follow-up was defined as eGFR <60 ml/min/1.73 m2, eGFR decline ≥40% from discharge, or albuminuria (>30 mg/L). MAKE-associated factors were investigated by binary logistic regression. Results: We assessed 655 patients (55±14 years, 45% ≥60 years, 46% female, 50% black). At hospital admission, eGFR was 82.2 ml/min/1.73 m2 (IQR:49.3–103.5). During hospital stay (median 15 days), peak SCr was 1.52 (IQR:1.02–3.26), 67% were admitted to intensive care units, 46% required intubation, 79% had acute kidney injury (35% at admission; 43% during hospitalization), and 14% needed dialysis. At hospital discharge, eGFR was 92.3 (IQR:64.3–107.4). After 7.8±1.6 months of follow-up, 14% of the patients showed eGFR decline >40% (median -5.4%; IQR:-26.7 – 30.2), and 16% of the patients showed eGFR <60 ml/min/1.73 m2. MAKE was found in 39% of the patients. The factors independently associated with MAKE were older age (odds ratio [OR]=1.54, 95%CI:1.11–2.14) and peak SCr (OR=1.20, 95%CI:1.10–1.32). Conclusion: Long-term kidney dysfunction was found in a large proportion of COVID-19 survivors, suggesting that kidney long COVID might be a significant health problem. Older age and peak SCr during hospitalization were independent risk factors associated with MAKE. Funding: Government Support – Non-U.S.Figure 1. eGFR overtime stratified by follow-up kidney function