FGF23 and chronic kidney disease: Overall, when 8 studies in patients on haemodialysis were pooled, a relative risk for the highest third of FGF23 versus the lowest third of FGF23 of 1.5 (95% CI 1.29–1.73) for all-cause mortality and of 1.42 (95% CI 0.96–2.39) for cardiovascular mortality was found the meta-analysis by Marthi et al. [71] Remarkably, the association of FGF23 with mortality is stronger in CKD patients not on dialysis despite much lower absolute levels of FGF23 [45, 46, 49, 53, 72–75].