Evidence of healing of secondary hyperparathyroidism in chronically hemodialyzed uremic patients treated with long-term intravenous calcitriol.

The aim of this study was to assess the effect of a long-term course of high-dose i.v. pulses of calcitriol (CLT) on hyperparathyroid bone disease (HBD) and functional mass of parathyroid glands of chronically hemodialyzed uremic (CHU) patients. We prospectively studied nine CHU patients treated with CLT, 30 ng/kg/body wt, i.v., thrice weekly over a period of eight months. Plasma concentrations of intact parathyroid hormone (iPTH), bone GLA protein (bGLA) and bone isoenzyme of alkaline phosphatase (biALP) were sampled throughout. Transiliac bone biopsies were made before and after the start of CLT therapy. Double scanning scintigraphy of the neck with 201Tl-99Tc was made before, during and eight months after the start of the treatment. All patients but one, who later responded to higher than planned CLT doses, had significant decreases of plasma iPTH (F = 76; P < 0.0001; ANOVA). The mean pretreatment value of PTH was 966 +/- 160 (mean +/- SE) pg/ml and it had decreased significantly by the first week (T = 2.4, P < 0.04), and had fallen an average of 80% by the 35th week. Ionized plasma calcium concentration was 1.19 +/- .01 mmol/liter which rose significantly (F = 13.5; P < 0.0001) by the 14th week to maximal peak levels, averaging 1.34 +/- .02 mmol/liter. Changes in biALP were parallel to those of iPTH, while bGLA tended to increase immediately after the start of the therapy and to significantly decrease thereafter (T = 3.2; P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)