FGF23 and chronic kidney disease: Several smaller studies have also examined this relationship in maintenance hemodialysis patients, but the results have been inconsistent.33, 34, 35, 36 Of note, a recent ancillary study of the Chronic Renal Insufficiency Cohort (CRIC) study44 demonstrated that individuals with rapidly rising FGF23 trajectories were at >15-fold higher risk of death than those with stable FGF23 levels.