Ginsberg C, Zelnick LR, Block GA, et al. - Given despite the use of phosphate binders to lower phosphate, there is a lack of understanding of the impacts of particular phosphate binder types on vitamin D metabolism, and therefore, researchers assessed alterations in serum levels of vitamin D metabolites including 24,25-dihydroxyvitamin D₃ [24,25(OH)₂D₃], 1,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃], the ratio of 24,25(OH)₂D₃ to 25-hydroxyvitamin D [the vitamin D metabolite ratio (VMR)] and the ratio of serum 1,25(OH)₂D to 25-hydroxyvitamin D in this secondary analysis of the Phosphate Normalization Trial wherein randomization of patients with moderate to advanced chronic kidney disease was done to receive either placebo, sevelamer carbonate, lanthanum carbonate or calcium acetate for 9 months. A 0.6 ng/mL and 13.5 pg/ng rise in 24,25(OH)₂D and VMR, respectively, and a 5.2 pg/mL decline in 1,25(OH)₂D was observed in relation to randomization to the calcium acetate arm vs placebo. A 0.5 ng/mL and 11.8 pg/ng decrease in 24,25(OH)₂D₃ and VMR, respectively, was evident in relation to randomization to sevelamer carbonate. Overall, findings revealed unique alterations in vitamin D metabolism that were consequent to administration of different phosphate binders to patients with moderate to severe CKD.