Strugnell et al. [19], conducted a post hoc analysis of aggregated data from two phase 3 studies by Sprague et al. [17, 43] to examine possible relationships between post-treatment 25(OH)D quintile and associated changes in factors relevant to CKD-mineral and bone disorder, including plasma intact parathyroid hormone, serum bone turnover markers, calcium, phosphorus, intact FGF23 and vitamin D metabolites, estimated glomerular filtration rate, and urine calcium/creatinine ratio. Here, FGF23 is linked to chronic kidney disease.