Acute kidney injury (AKI) is common in patients hospitalized with COVID-19 and urinary biomarkers at admission may predict its development and prognosis, according to an ongoing, prospective single-center study.

At a median 4 days after hospital admission, stage 1 AKI developed in 12 (52.2%) of 23 patients included in the study, Faeq Husain-Syed, MD, of University Hospital Giessen and Marburg in Germany, and colleagues reported in Nephrology Dialysis Transplantation. Ten of the 12 cases received treatment in an intensive care unit.

At a median of 10 days post-admission, 1 of the 5 patients whose AKI did not resolve progressed from stage 1 to stage 2, and 4 progressed from stage 1 to stage 3. Three patients required renal replacement therapy (RRT) but died, according to the investigators.

Patients in whom AKI developed had lower renal function compared with those who did not experience AKI. Of the 23 patients, 19 (82.6%) had increased proteinuria independent of subsequent AKI. Proteinuria was greater in AKI compared with non-AKI patients (442.0 vs 142.0 mg/g creatinine). All patients had an elevated renal resistance index on admission.


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The study revealed that proteinuria and ɑ1-microglobulin excretion at admission were greater among patients who experienced AKI compared with those who did not. The median ɑ1-microglobulin excretion was higher among AKI patients who experienced progression of AKI stage compared with those who did not (87.2 vs 34.1 mg/g creatinine). Median proteinuria levels, however, did not differ between AKI progressors and AKI non-progressors (442.3 vs 459.9 mg/g creatinine).

Among the patients with AKI, those who progressed from stage 1 to stage 2 or 3 had higher levels of urinary tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7), which have been identified as novel biomarkers for predicting moderate to severe AKI.

According to the investigators, ɑ1-microglobulin excretion and TIMP-2 and IGFBP7 on admission appear to improve risk stratification for severe outcomes (stage 3 AKI, RRT, and death). They pointed out, however, that the number of patients who reached those outcomes was quite small.

Reference

Husain-Syed F, Wilhem J, Kassoumeh S, et al. Acute kidney injury and urinary biomarkers in hospitalized patients with coronavirus disease 2019 [published online July 20, 2020]. Nephrol Dial Transplant. doi: 10.1093/ndt/gfaa162