Urinary Biomarkers Predict Weaning From Acute Dialysis Therapy

By LabMedica International staff writers
Posted on 29 Nov 2022

Acute kidney injury is associated with a higher risk of chronic kidney disease (CKD), end-stage renal disease, and long-term adverse cardiovascular effects. Critically ill patients with acute kidney injury (AKI) requiring renal replacement therapy (RRT) have a poor prognosis.

Several urinary biomarkers that can predict the development of AKI have been identified, including proximal renal tubular damage markers (e.g., liver-type fatty acid–binding protein [L-FABP], hemojuvelin [HJV], and kidney injury molecule 1 [KIM-1]), distal renal tubular damage markers (e.g., neutrophil gelatinase-associated lipocalin [NGAL] ), and inflammation markers (e.g., C-C motif chemokine ligand 14 [CCL14] and interleukin 18 [IL-18].


Image: ELISA kit for liver-type fatty acid–binding protein (L-FABP). The level of L-FABP present in urine reflects the level of renal tubular dysfunction (Photo courtesy of Sekisui Medical Co)

Nephrologists at the National Taiwan University Hospital (Taipei, Taiwan) and their colleagues prospectively recorded and analyzed clinical variables at several time points: (1) before starting renal replacement therapy (RRT), (2) at the time of weaning off RRT, and (3) 24 hours after stopping RRT. A total of 140 critically ill patients who received RRT at a multicenter referral hospital from August 2016 to January 2019 were enrolled.

At the time of stopping RRT, urine samples were collected and stored at −80 °C until analysis. The urine concentrations of novel AKI biomarkers were determined using enzyme-linked immunosorbent assay kits: renal L-FABP, (Sekisui Medical Co, Ltd, Tokyo, Japan); KIM-1, NGAL, CCL14 and IL-18, (R&D Systems, Minneapolis, MN, USA), HJV, (Cloud-Clone Corp, Katy, TX, USA).

The investigators reported that the 90-day mortality rate was 13.6% (19/140), and 47.9% (67/140) of the patients were successfully weaned from RRT. Cluster analysis showed that the following biomarkers were correlated with estimated glomerular filtration rate at the time of weaning off RRT: urinary neutrophil gelatinase-associated lipocalin, kidney injury molecule 1, hemojuvelin, C-C motif chemokine ligand 14, interleukin 18, and liver-type fatty acid–binding protein (L-FABP). Among these, urinary L-FABP/creatinine (uL-FABP/Cr) at the time of weaning off RRT showed the best predictive performance for mortality (area under the receiver operating characteristic curve = 0.79).

The authors concluded that nearly half of the critically ill AKI-RRT patients in this study were successfully weaned from acute RRT. They demonstrated that uL-FABP/Cr level at the time of weaning from RRT independently predicted being dialysis free for more than 90 days and all-cause mortality. They also showed that a cutoff value of uL-FABP/Cr (log) level ≤ 2.2 μg/g Cr may be useful for clinical decision-making for AKI-RRT patients who attempt to wean off RRT. uL-FABP/Cr can be combined with SOFA score at the time of weaning off RRT to predict being dialysis free and 90-day mortality. The study was published in the November, 2022 issue of the journal Archives of Pathology & Laboratory Medicine.

Related Links:
National Taiwan University Hospital
Sekisui Medical Co, Ltd
R&D Systems
Cloud-Clone Corp


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