Early therapy of renal bone disease with calcitriol: a prospective double-blind study.

The value of calcitriol administration in the management and prevention of renal bone disease was studied in a prospective double-blind manner in 16 patients with chronic renal impairment (creatinine clearance 20 to 59 ml per min). They were given either calcitriol at a dose of 0.25 to 0.5 micrograms daily (eight patients), or placebo. Transiliac crest bone biopsies were performed before entrance into the study and after 12 months of experimental observation. None of the patients were symptomatic or had biochemical or radiological evidence of bone disease. Of the thirteen patients who completed the study, initial serum 1,25(OH)2D levels were low in seven patients and parathyroid hormone levels were elevated in seven patients. Bone histology was abnormal in all patients. Calcitriol treatment was associated with a significant fall in serum phosphorus concentrations and alkaline phosphatase levels as well as with histological evidence of an amelioration of hyperparathyroid changes. In contrast to previous reports, no deterioration of renal function attributable to the treatment occurred, perhaps because a modest dose of calcitriol was employed combined with meticulous monitoring. Further investigation is required to determine whether alternative therapeutic strategies (smaller doses or intermittent therapy) may avoid the potential for suppressing bone turnover to abnormally low levels in the long term.