C-terminal and intact FGF23 in critical illness and their associations with acute kidney injury and in-hospital mortality

Background: FGF23 proved its value in prognostication of cardiovascular events and mortality among renal patients and general population. Limited data exist whether FGF23 may have any use in prediction of negative outcomes among critically ill patients admitted to intensive care unit (ICU). Methods: Single center cohort study performed among patients admitted to ICU. The primary exposure was FGF23 plasma concentration measured within 24 h of ICU admission. The primary outcome was incident Acute Kidney Injury (AKI) and in-hospital mortality during the ICU stay. Results: The study enrolled 79 patients admitted to ICU. C-terminal FGF23 (cFGF23) but not intact FGF23 (iFGF23) concentration was significantly elevated in patients, who acquired AKI and non-survivors (p <.001). ROC analysis of cFGF23 yielded an AUC of 0.81 and 0.85 for prediction of incident AKI and death during ICU stay, respectively. Multivariate analysis showed higher odds for AKI (OR 1.80; 95% CI 1.10-2.96) and in-hospital mortality (OR 2.85; 95% CI 1.60-5.06) for one unit increase of log transformed cFGF23. Conclusions: cFGF23 measurement may serve as a novel biomarker for incident AKI and death among critically ill patients.