Urine test in patients admitted with acute COVID-19 predicts kidney injury and death, reports a recent study.
USA: According to the study, in COVID-19 patients, elevated urinary NGAL (uNGAL) was associated with acute kidney injury (development), increased duration and severity of AKI, prolonged hospitalization, the degree of histopathological acute tubular injury, need for dialysis, and death. The findings of the study were presented at the American Society of Nephrology (ASN) Kidney Week 2021.
Kidney injury occurs commonly in COVID-19 patients, but serum creatinine (SCr) is not a sensitive or specific marker of kidney injury. Katherine Xu, Columbia University Irving Medical Center, New York, New York, United States, and colleagues hypothesized that measurement of molecular markers of tubular injury can diagnose COVID-19 associated kidney injury and predict a poor prognosis in a prospective cohort study.
The study included 444 consecutive COVID-19 patients in a New York City Emergency Department from March to April 2020. Blood and urine were collected simultaneously at hospital admission and within 1 day of a positive SARS-CoV-2 test in 70% of patients. Urine NGAL and KIM-1 assays were blinded to clinical data.
Primary outcomes included the AKI diagnosis as defined by AKIN criteria, as well as its duration and severity.
Based on the study, the researchers found the following:
· Elevated urinary NGAL (uNGAL) levels were associated with SCr based AKI (267±301 vs. 96±139 ng/mL).
· uNGAL level >150 ng/mL had 80% specificity and 75% sensitivity to diagnose AKIN stage 2 AKI or higher.
· Higher uNGAL levels were associated with sustained AKI [aOR per SD of uNGAL: 2.67 (1.81-4.06), need for dialysis (aOR: 3.67), shock (aOR: 1.64), prolonged length of stay (aHR: 1.22), and death [aOR=1.62], independent of baseline SCr and pre-existing co-morbidities.
· These associations were also preserved after adjusting for proteinuria measured in the same urine sample.
· NGAL is typically transcribed by distal nephron segments but in COVID-19 kidney biopsies with widespread histopathologic acute tubular injury (ATI), NGAL mRNA expression included proximal tubules.
The authors concluded, "elevated uNGAL in patients admitted with acute COVID-19 was associated with the development of AKI, increased severity and duration of AKI, the degree of histopathological acute tubular injury, shock, prolonged hospitalization, need for dialysis, and death."
Reference:
PO0172 — 2021 ASN, Urine Test Predicts Kidney Injury and Death in COVID-19