Acute kidney injury and mortality risk in older adults with COVID-19.

BACKGROUND Research regarding COVID-19 and acute kidney injury (AKI) in older adults is scarce. We evaluated risk factors and outcomes of AKI in hospitalized older adults with and without COVID-19. METHODS Observational study of patients admitted to two geriatric clinics in Stockholm from March 1st to June 15th, 2020. The difference in incidence, risk factors and adverse outcomes for AKI between patients with or without COVID-19 were examined. Odds ratios (OR) for the risk of AKI and in-hospital death were obtained from logistic regression. RESULTS Three hundred-sixteen older patients were hospitalized for COVID-19 and 876 patients for non-COVID-19 diagnoses. AKI occurred in 92 (29%) patients with COVID-19 vs. 159 (18%) without COVID-19. The odds for developing AKI were higher in patients with COVID-19 (adjusted OR, 1.70; 95% confidence interval [CI] 1.04-2.76), low baseline kidney function as depicted by estimated glomerular filtration rate (eGFR) [4.19 (2.48-7.05), for eGFR 30 to  < 60 mL/min, and 20.3 (9.95-41.3) for eGFR < 30 mL/min], and higher C reactive protein (CRP) (OR 1.81 (1.11-2.95) in patients with initial CRP > 10 mg/L). Compared to patients without COVID-19 and without AKI, the risk of in-hospital death was highest in patients with COVID-19 and AKI [OR 80.3, 95% CI (27.3-235.6)], followed by COVID-19 without AKI [16.3 (6.28-42.4)], and by patients without COVID-19 and with AKI [10.2 (3.66-28.2)]. CONCLUSIONS Geriatric patients hospitalized with COVID-19 had a higher incidence of AKI compared to patients hospitalized for other diagnoses. COVID-19 and reduced baseline kidney function were risk factors for developing AKI. AKI and COVID-19 were associated with in-hospital death.