Fibroblast growth factor-23 as an early biomarker of ischemic acute kidney injury after partial nephrectomy: prospective observational study

Partial nephrectomy (PN) is a clinical model for ischemic acute kidney injury (AKI), which occurs in up to 39% of cases and increases long-term morbidity and mortality. Given that Fibroblast Growth Factor-23 (FGF23) rises rapidly with kidney dysfunction, this study assessed whether intraoperative FGF23 elevation predicts ischemic AKI after PN. Twenty-seven PN patients and sixteen controls with non-ischemic surgical kidney injury were enrolled. Blood samples for FGF23 ELISA were collected at baseline, 1 h post-ischemia (PN) or at the first surgical access (controls), and at 24 and 72 h postoperatively. AKI was defined by KDIGO criteria. AKI occurred in 44.4% of partial nephrectomy (PN) patients. Only patients with PN who developed AKI showed a significant early rise in FGF23, averaging 18.6 ± 9.5 pg/mL (p < 0.0001) one hour post-ischemia. This early increase in FGF23 is predictive of AKI (AUC = 0.75; 95% CI: 0.56-0.95; P = 0.026). An optimal cut-off increase of 19.35 pg/mL offered 58.3% sensitivity and 93.3% specificity. Intraoperative FGF23 elevation predicts AKI after PN and may be an early marker of ischemic kidney injury. Validation in larger cohorts is required.