Serum uromodulin associates with kidney function and outcome in a cohort of hospitalised COVID-19 patients.

This study investigates the prevalence and evaluates the prognostic implications of acute kidney injury (AKI) in COVID-19 patients, with a novel emphasis on the evaluation of serum uromodulin (sUmod) as a potential kidney-specific biomarker. A cohort of hospitalised COVID-19 patients (n = 378) was examined for AKI using standard criteria. In addition to traditional urinary biomarkers, sUmod levels were analysed. Univariable and multivariable regression models were employed to evaluate the association of sUmod and AKI and in-hospital mortality. Levels of sUmod were significantly lower in patients with CKD (91.8 ± 60.7 ng/ml) compared to patients with normal kidney function (204.7 ± 91.7 ng/ml; p < 0.001). 151 patients (40.0%) presented with AKI at the time of hospital admission or developed an AKI during hospitalization. 116 patients (76.8%) had an AKI already at the time of hospital admission. COVID-19 patients with AKI had significantly lower levels of sUmod compared to patients without AKI during hospitalisation (124.8 ± 79.5 ng/ml) vs 214.6 ± 92.3 ng/ml; p < 0.001). The in-hospital mortality rate in this cohort of COVID-19 patients was 15.3%. Patients with AKI had a higher probability for in-hospital death (OR 5.6, CI 1.76 to 17.881, p = 0.004). Patients who died during hospital stay, had significantly lower sUmod levels (129.14 ± 89.56 ng/ml) compared to patients surviving hospitalisation (187.71 ± 96,64 ng/ml; p < 0.001). AKI is frequently associated with COVID-19 in hospitalized patients. Serum uromodulin may emerge as a promising biomarker for AKI in COVID-19 patients. Further research is warranted to explore its clinical application and refine risk stratification in this patient population.