Combined tests may improve severe AKI detection, prediction in children

Combining Renal Angina Index (RAI) and urinary Neutrophil Gelatinase Associated Lipocalin (uNGAL) tests may help clinicians to detect and predict the development of severe acute kidney injury (AKI) in children admitted to the PICU*, according to a study presented at ASN Kidney Week 2019.

“Integration of the RAI and uNGAL assessments can be used early in the PICU course to identify patients truly at risk for AKI and its associated morbidity,” said study lead author Kelli Krallman, a research nurse at Cincinnati Children's Hospital Medical Center in Cincinnati, Ohio, US.

Researchers conducted a study involving 627 children who underwent an automated RAI assessment within 12 hours after PICU admission. Of these, 63 children were found to be RAI-positive (defined as an RAI score of ≥8) and were referred for an additional uNGAL assessment (cut-off value of at least 150 ng/mL). [ASN Kidney Week 2019, abstract SA-OR017]

On day 2–4 in the PICU, patients who were RAI-positive children had a significantly higher rate of severe AKI compared with those who were RAI-negative (38.0 percent vs 1.8 percent; p<0.001).

When an additional uNGAL test was performed, a significantly higher rate of severe AKI was also observed among patients positive for both RAI and uNGAL (55.5 percent vs 17.6 percent; p<0.0001) compared with patients tested negative for both RAI and uNGAL.

Of note, the need for renal replacement therapy was found to be higher among the RAI-positive group compared with the RAI-negative group (13.0 percent vs 0.4 percent; p<0.001).

RAI-positive patients also experienced a significantly longer stay in the PICU (4.6 vs 3.1 days; p<0.02) and hospital (17.8 vs 7.5 days; p<0.001) than the RAI-negative patients.

However, there was no difference in the occurrence of fluid overload between the RAI-positive and RAI-negative patients (p=0.14 vs p=0.11).

“The RAI alone continues to be a good rule-out test for severe AKI in the PICU, and [the] addition of uNGAL is promising for improved severe AKI prediction,” said the researchers, recommending that “additional research needs to be conducted on a larger sample size to better assess the clinical relevance of the RAI-[u]NGAL model in predicting severe AKI and other relevant outcomes”.

*PICU: Paediatric intensive care unit