Urinary Biomarkers as Predictors of AKI in COVID-19

Acute kidney injury (AKI) is a common complication among patients hospitalized with COVID-19. There are only a few reports of use of urinary biomarkers in COVID-19 and no available data comparing the prognostic use of individual biomarkers to predict adverse outcomes.

Diana Racovitan, MD, and colleagues conducted a prospective monocentric study on the value of urinary biomarkers in predicting the composite end point of transfer to the intensive care unit (ICU), the need for renal replacement therapy, mechanical ventilation, and in-hospital mortality. Results were reported online in Clinical Nephrology [doi:10.5414/CN110952].

The cohort included 41 patients hospitalized for COVID-19.  Shortly after admission, urine samples were obtained in order to assess neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), calprotectin, and vascular noninflammatory molecule-1 (vanin-1).

The researchers identified calprotectin as a predictor of a severe course of COVID-19 requiring admission to the ICU (area under the curve [AUC] 0.728; P=.016). Positive and negative predictive values were 78.6% and 76.9%, respectively, using a cut-off concentration of 127.8 ng/mL. NGAL tended to predict AKI in patients with COVID-19; however, the association was not statistically significant (AUC 0.669; P=.052).

NGAL was the best predictor of in-hospital mortality (AUC 0.674; P=.077). There were no statistically significant associations between KIM-1 and vanin-1 for any of the end points of interest.

In conclusion, the authors said, “While KIM-1 and vanin-1 did not provide prognostic clinical information in the context of COVID-19, the present study shows that urinary calprotectin is moderately predictive of the need for intensive care unit (ICU) admission, and NGAL may be modestly predictive of AKI in COVID-19. Calprotectin and NGAL show promise as potential helpful adjuncts in the identification of patients at increased risk of poor outcomes or complications in COVID-19.”