Urinary Biomarkers Predict Severe Kidney Injury in Hospitalized COVID-19 Patients

The study led by Johns Hopkins University School of Medicine (Baltimore, MD, USA) investigated the association between urinary biomarkers with adverse kidney outcomes among patients hospitalized with COVID-19. Urinary biomarkers have been associated with adverse kidney outcomes in other settings and may provide additional prognostic information in patients with COVID-19.

Acute kidney injury (AKI) is common in patients with COVID-19 and associated with poor outcomes. Risk factors for the development of AKI in the setting of COVID-19 include black race, male sex, age over 50 years, diabetes mellitus, hypertension, obesity, and heart failure. The mechanism for this higher AKI risk remains unexplained. The long-term impact of COVID-19 is also uncertain from both kidney-specific and more global standpoints, with growing concern for the disease’s long-term physiological and psychological effects.

Biomarkers of kidney injury, inflammation, and repair may offer further insight beyond current standard methods of characterizing COVID-19-associated AKI. Biomarkers can help to differentiate various types of kidney injury and may be uniquely helpful in quantifying tubular injury in COVID-19. In their study, the researchers explored the association of urinary biomarkers of kidney injury, inflammation, and repair with severe AKI and death in patients hospitalized with COVID-19. Additionally, they evaluated biomarkers in patients with normal serum creatinine to identify the subset of patients with sub-clinical AKI, which has been consistently associated with adverse outcomes. To estimate the magnitude of tubular injury in COVID-19 and provide insight into pathogenesis, the researchers compared biomarkers of injury, inflammation, and repair in the kidney across different AKI settings.

The researchers found that certain biomarkers including epidermal growth factor and kidney injury molecule-1, among others, were associated with stage 3 AKI, dialysis, and death up to 60 days in patients hospitalized with COVID-19. These findings suggest that these studied biomarkers may help identify patients at particularly high risk for adverse kidney outcome and improve risk stratification of patients admitted with COVID-19. The degree of tubular injury and inflammation did not appear to be overtly higher than in other common settings of AKI. Subclinical AKI, as defined by elevations in urinary biomarkers, was present in 30-50% of individuals who did not manifest clinical AKI. According to the researchers, further studies are needed to validate these findings and assess the association of the biomarkers with risk for CKD as well as the potential long-term consequences associated with subclinical AKI after COVID-19.

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Johns Hopkins University School of Medicine