Early proximal tubular injury in COVID-19 related ARDS: the URICOV study

Abstract Background : During COVID-19, renal impairment is the most frequent after lung impairment and is associated with a poor prognosis particularly in intensive care unit (ICU). In this work we aimed to assess the existence and incidence of early renal dysfunction and its prognostic value in patients with COVID-19-related acute respiratory distress syndrome (ARDS) and to compare them with patients with non-COVID-19-related ARDS. Methods : This prospective multicenter study was conducted in 3 ICUs. Patients aged 18 years and older with invasive mechanical ventilation for ARDS were enrolled. Precise evaluation of renal dysfunction markers including urinary proteins electrophoresis (UPE) and quantification, was performed within 24 hours after mechanical ventilation onset. Results : From March 2020 to December 2021, 135 patients in ICU for ARDS were enrolled: 100 COVID-19 ARDS and 35 non-COVID-19 ARDS. UPE found more tubular dysfunction in COVID-19 patients (68% vs. 21.4%, p<0.0001) and more normal profiles in non-COVID-19 patients (65.0% vs. 11.2%, p=0.0003). COVID-19 patients significantly displayed early urinary leakage of tubular proteins like beta-2-microglobulin and free-light chains, tended to display more frequently acute kidney injury (AKI) (51.0% vs 34.3%, p=0.088), and had longer mechanical ventilation (20 vs. 9 days, p<0.0001) and longer ICU length of stay (26 vs. 15 days, p<0.0001). In COVID-19 ARDS, leakage of free lambda light chain was significantly associated with the onset of KDIGO ≥2 AKI (OR: 1.014, 95% CI [1.003-1.025], p=0.011). Conclusion: Patients admitted to the ICU for COVID-19-related ARDS display a proximal tubular dysfunction, prior to the onset of AKI, which predicts AKI. Proximal tubular damage seems an important mechanism of COVID-19-induced nephropathy. Analysis of urinary proteins is a reliable and non-invasive tool to assess proximal tubular dysfunction in the ICU. Trial Registration: Registered retrospectively with www.clinicaltrials.gov (NCT05699889) 26 January 2023.