FGF23 and vitamin D deficiency: This study also demonstrated that the number of participants with isolated FGF23 excess is > 6-fold more than isolated PTH excess despite the high prevalence of vitamin D deficiency and an eGFR threshold of a significant increase is higher for FGF23 comparing with PTH (57.8 59 vs 46.9 mL/min/1.73 m2) [66].