Urinary Biomarkers Can Predict Weaning From Acute Dialysis Therapy in Critically Ill Patients

Abstract

Context.— Critically ill patients with acute kidney injury (AKI) requiring renal replacement therapy (RRT) have a poor prognosis. Several urinary AKI biomarkers have been proposed to predict renal recovery, but with limited discriminatory ability. Objective.— To validate the predictive performances of novel biomarkers to identify which critical patients with AKI may successfully wean from RRT. Design.— We prospectively recorded and analyzed clinical variables at several time points: (1) before starting 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. The outcomes of interest were the ability to wean from RRT and 90-day mortality. Results.— The 90-day mortality rate was 13.6% (19 of 140), and 47.9% (67 of 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). Taking mortality as a competing risk, Cox proportional hazards analysis indicated that a low uL-FABP/Cr (log) level was an independent prognostic factor for weaning from RRT (subdistribution hazard ratio, 0.35; P = .01). Conclusions.— uL-FABP/Cr at the time of weaning off RRT could predict weaning from RRT and 90-day mortality.