Although FGF23 acts in a compensatory manner towards these elevating phosphate levels, clinical CKD studies have demonstrated powerful and dose-dependent associations between elevations in serum levels of FGF23 and CKD-associated pathologies, such as systemic inflammation, anemia and cardiovascular mortality, which is the leading cause of death across all stages of CKD [2,155,156,157,158]. This evidence concerns the gene FGF23 and anemia (phenotype).