Effects of calcifediol supplementation on markers of chronic kidney disease-mineral and bone disorder in dogs with chronic kidney disease.

Abstract

BackgroundChronic kidney disease‐mineral and bone disorder (CKD‐MBD) in dogs is associated with hypovitaminosis D, increased parathyroid hormone (PTH), and increased fibroblast growth factor‐23 (FGF‐23) concentrations. Best practice for vitamin D metabolite supplementation in CKD‐MBD remains unknown.ObjectiveTo provide an extended‐release calcifediol supplement to dogs with CKD and to measure its effects on variables indicative of CKD‐MBD.AnimalsTen dogs with International Renal Interest Society stages 2 and 3 CKD.MethodsIn a prospective study, dogs received a calcifediol supplement for 84 days. Serum 25‐hydroxyvitamin D (25[OH]D), 1,25‐dihydroxyvitamin D (1,25[OH]2D), 24,25‐dihydroxyvitamin D (24,25[OH]2D), creatinine, calcium, phosphorus, PTH, plasma FGF‐23 concentrations, and urine profiles were measured monthly during supplementation. Urine calcium to creatinine (UCa/Cr) ratios and fractional excretion of calcium, phosphorus, and sodium were determined.ResultsAll serum vitamin D metabolite concentrations increased significantly by day 84 (P < .001): [25(OH)D (median 249.9 ng/mL; range, 149.7‐469.9 ng/mL) compared to baseline (median 50.2 ng/mL; range, 31.3‐66.0 ng/mL); 1,25(OH)2D (median 66.1 pg/mL; range, 56.9‐88.1 pg/mL) compared to baseline (median 37.3 pg/mL; range, 29.3‐56.7 pg/mL); 24,25(OH)2D (median 81.4 ng/mL; range, 22.1‐151.7 ng/mL) compared to baseline (median 15.4 ng/mL; range, 6.9‐40.6 ng/mL)]. There were no significant differences in calcium, phosphorus, PTH concentrations, UCa/Cr or fractional excretion of calcium. No dog developed ionized hypercalcemia. Plasma FGF‐23 concentrations increased by day 84 (median 1219 pg/mL; range, 229‐8824 pg/mL) compared to baseline (median 798 pg/mL; range, 103‐4.145 pg/mL) (P < .01).Conclusions and Clinical ImportanceCalcifediol supplementation for 84 days was well‐tolerated in dogs with IRIS stages 2 and 3 CKD. It remains to be determined how long‐term supplementation would affect CKD progression and QOL.