
Urinary Ba, a fragment of complement factor B, may be a biomarker and mediator of acute kidney injury (AKI) in critically ill patients, investigators suggest.
In a post hoc analysis of the EARLYARF randomized trial, investigators compared 124, 43, and 20 critically ill adults with KDIGO stage 1, 2, and 3 AKI, respectively, and 252 patients without AKI.
Urine Ba significantly increased along with AKI stage, Erin K. Stenson, MD, of the University of Colorado Anschutz Medical Campus in Aurora, and colleagues reported in Kidney International Reports. Urine Ba also was significantly higher in patients with persistent AKI compared with AKI recovery or no AKI. After adjustment for age and APACHE-II score, each doubling of urine Ba was significantly associated with 6.6-fold increased odds of persistent AKI beyond 48 hours, the investigators reported. This trend was observed among patients with AKI at ICU admission as well as those who developed AKI during their ICU stay.
Higher mean urine Ba was significantly associated with worse organ failure outcomes: 0.71 fewer days alive, 0.75 fewer ventilator-free days, 0.76 fewer inotrope-free days, and 0.74 fewer ICU-free days, Dr Stenson’s team reported.
Urine Ba values might be used to distinguish between AKI that recovers within 48 hours and persistent AKI, according to the investigators. Patients with urine Ba values suggesting AKI recovery might benefit from further fluid resuscitation, whereas those with values suggesting persistent AKI may benefit from conservative fluid resuscitation, optimization of hemodynamics, and avoidance of nephrotoxins.
Notably, urine Ba elevations corresponded with elevations in other biomarkers, including urine NGAL and KIM-1.
“Severe urine Ba elevation may identify which critically ill patient may benefit from factor B inhibition, which is currently being evaluated in clinical trials for other diseases.”
In an accompanying editorial, Daan P.C. van Doorn, MD, PhD, of Expert Center for Immune-mediated Kidney Diseases and Vasculitis at Maastricht University Medical Center in The Netherlands, and colleagues emphasized that urine Ba may identify patients at the highest risk for AKI at the earliest possible stage of disease. “These insights could make it possible for future research into innovative treatments for patients who do not recover from AKI, an area still in need of advancement.”
References:
Stenson EK, Edelstein CE, You Z, et al. Urine complement factor Ba identifies persistent acute kidney injury and organ failures in critically ill adults. Kidney Int Rep. Published online November 24, 2024. doi:10.1016/j.ekir.2024.11.030
van Doorn DPC, Soares dos Santos Jr AC, Timmermans SAMEG, et al. Urinary complement factor Ba: a new tool for early detection of acute kidney injury. Kidney Int Rep. Published online November 24, 2024. doi:10.1016/j.ekir.2024.11.023
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