The clinical evaluation of maxacalcitol on therapy for secondary hyperparathyroidism of chronic hemodialysis patients

The spectrum of bone disease in end-stage renal failure is changing, but secondary hyperparathyroidism is still a troublesome complication. The vitamin D3 analog, maxacalcitol, has reduced calcemic action compared to vitamin D3, but show equivalent suppression of parathyroid hormone(PTH) secretion. In the first step of the study, we investigated the severity of secondary hyperparathyroidism in 670 chronic hemodialysis patients, whose age, sex(male/female), and duration on dialysis were 63.5 +/- 12.4 years, 383/287, and 7.3 +/- 6.0 years, respectively. The number of patients with serum intact-PTH concentrations over 300 pg/ml was 118. Most patients in this group(87.3%) were already being prescribed oral vitamin D3 analog. In the second step, maxacalcitol was administered intravenously, instead of the oral vitamin D3 analog, to 92 patients selected from the above-described group. The age, sex(male/female), and duration of dialysis were 59.4 +/- 11.5 years, 56/36, and 7.3 +/- 6.0 years, respectively. Serum intact-PTH concentration and alkaline phosphatase activity decreased significantly, from 612.3 +/- 32.7 to 414.2 +/- 26.8 pg/ml, and from 329.3 +/- 17.3 to 277.0 +/- 12.5 IU/l, respectively. Serum calcium phosphorous concentration increased significantly, and maxacalcitol administration was interrupted because of hypercalcemia in 17 patients(18.5%). Serum intact-PTH concentration did not decrease in patients with serum Ca concentrations of 10.5 mg/dl or more before maxacalcitol therapy. In conclusion, maxacalcitol suppressed PTH secretion more effectively in hemodialysis patients with secondary hyperparathyroidism than did oral active vitamin D3 therapy, especially in patients with serum Ca concentrations lower than 10.5 mg/dl.