A single preoperative FGF23 measurement is a strong predictor of outcome in patients undergoing elective cardiac surgery: a prospective observational study

Timo Speer, Heinrich V Groesdonk, Beate Zapf, Vanessa Buescher, Miriam Beyse, Laura Duerr, Stella Gewert, Patrizia Krauss, Aaron Poppleton, Stefan Wagenpfeil, Danilo Fliser, Hans-Joachim Schaefers, Matthias Klingele

Several scoring systems have been developed to predict postoperative mortality and complications in patients undergoing cardiac surgery. However, these computer-based calculations are time- and cost-intensive. Therefore a simple but highly predictive test for postoperative risk would be of clinical benefit with respect to increasingly scarce hospital resource. We therefore assessed the predictive power of fibroblast growth factor-23 (FGF-23) compared with an established scoring system. Prospective interdisciplinary observational study at the Saarland University Medical Center including 859 patients undergoing elective cardiac surgery between 01/2010 and 03/2011 with a median follow-up after discharge of 822 days. We compared a single preoperative measurement of FGF-23 as prognostic tool with the 18 parameters comprising EuroSCORE II, with respect to postoperative mortality, acute kidney injury, non-occlusive mesenteric ischemia, clinical course and long-term outcome. Preoperative FGF-23 levels were highly predictive of postoperative outcome and complications. The predictive value of FGF-23 for mortality in the receiver operating characteristic (ROC) curve was greater than the EuroSCORE II (AUC 0.800 vs. 0.725). Moreover, preoperative FGF-23 independently predicted postoperative acute kidney injury and non-occlusive mesenteric ischemia comparably to the EuroSCORE II. Finally, FGF-23 was found to be an independent predictor of clinical course parameters including: duration of surgery, ventilation time, and length of stay. In patients undergoing elective cardiac surgery, a simple preoperative FGF-23 measurement is a powerful indicator of surgical mortality, postoperative complications, and long term outcome. Its utility compares to the widely used EuroSCORE.