Edmonston D, Wojdyla D, Mehta R, et al. - Through a prospective cohort study of participants in the Chronic Renal Insufficiency Cohort Study (n = 3,789), researchers determined whether fibroblast growth factor 23 (FGF-23) testing could enhance clinical risk prediction in individuals with chronic kidney disease. At 3 years of follow-up, adding a single baseline value of cFGF-23 to a base prediction model updated prognostication of all-cause mortality, and heart failure (HF) admission, though not cardiovascular (CV) mortality, end-stage renal disease (ESRD), or atherosclerotic events. For any of the 3-year outcomes, the net reclassification index did not reach statistical importance. In analyses of the 5- and 8-year outcomes, the incremental predictive utility of the cFGF-23 level decreased. For each outcome, the cFGF-23 models outperformed the phosphate model. Therefore, single measurements of cFGF-23 improve the prognostication of risks for all-cause mortality and HF admission, however, not CV mortality, ESRD, or atherosclerotic events, in individuals with chronic kidney disease.