Controlled trial of the effects of 1,25-dihydroxycholecalciferol in patients treated with regular dialysis

In a double-blind controlled study, 15 patients received 1,25-dihydroxycholecalciferol (1,25[OH]2D3) (0.5-1.5 microgram/day) and 16 patients received vitamin D3 (D3) (400-1,200 IU/day). The patients receiving 1,25(OH)2D3 had a rise in mean serum calcium concentration from 9.05 +/- 0.15 to 10.25 +/- 0.20 mg/dl (p less than .001) with a return to 9.37 +/- 0.16 (p less than .001) in the post-control period; however, hypercalcemia (greater than 11.5 mg/dl) occurred in 5 of 15 patients. Likewise, patients who received 1,25(OH)2D3 but not those given D3 had a reversible decrease in immunoreactive parathyroid levels. 9 of 12 patients given D3 had serial iliac crest bipsies showing histologic deterioration, while 6 of 7 patients who received 1,25(OH)2D3 were improved or unchanged (p less than 0.025). Bone mineral and calcium content decreased in patients on D3 (p less than .05) but not in those on 1,25(OH)2D3. We conclude that the administration of 1,25(OH)2D3 to dialysis patients: (1) has a calcemic effect. (2) decreases levels of immunoreactive parathyroid hormone, and (3) is associated with histologic improvement in bone disease.