Open-Label, Controlled Study on the Metabolic and Absorptiometric Effects of Calcitriol in Involutional Osteoporosis

Abstract

Calcitriol 0.5µg twice daily, in combination with a low dietary calcium intake, was administered for 2 years to 35 women (mean age 64.6 ± 8.3 years) with involutional osteoporosis; 45 women (mean age 63.5 ± 8.7 years) with osteoporosis ingested dietary calcium 1000 mg/day and were considered a control group. Total body bone mineral density (BMD) and BMD of major anatomical areas were measured (Lunar DPX). In the calcitriol group, significant increases in serum and urinary calcium levels were observed after 12 and 24 months; urinary hydroxyproline excretion did not change significantly. No differences in blood urea nitrogen or serum creatinine were observed during calcitriol therapy, and none of the patients experienced symptomatic renal lithiasis. Increases in total body, spine and leg BMD were observed after 12 and 24 months of calcitriol therapy (+0.63%, +1.15% and +0.56%, and +0.85%, +1.37% and +0.35%, respectively). In the control group, total body BMD and BMD of the spine, trunk, arms and legs decreased significantly. The mean percentage BMD differences between the 2 study groups were statistically significant. In the control group, spinal height declined progressively and significantly from baseline (−1.61% and −3.02% after 12 and 24 months, respectively), while in calcitriol-treated patients the decrease was less marked (−1.11% and −1.15%, respectively): the difference between the 2 groups was statistically significant (p < 0.01) after 24 months.