Effect of I,25-dihydroxycholecalciferol in renal osteodystrophy.

A 23-year-old man with medullary cystic disease had been undergoing hemodialysis for 5 years and had become confined to a wheelchair because of renal osteodystrophy. He was treated with 125-dihydroxycholecalciferol, 2.0 mug (later 1.0 mug) three times a week, administered by way of the venous end of the dialysis machine. Within 1 month bone pain lessened and his ability to stand and walk improved. By 3 months he was walking short distances and by 5 months, long distances. Calcium balance was near zero before treatment and was strongly positive during treatment. Bone mineral content in the lower femur, measured by photon absorptiometry, increased at a rate of 32.2% per year. In contrast, 26 other patients on long-term hemodialysis had a mean loss of bone mineral content of 14.0% per year. Radiographs taken during treatment showed a decrease in subperiosteal bone resorption and healing of a pseudofracture. A significant decrease in the mean serum alkaline phosphatase value was noted during treatment, but no significant changes in mean serum calcium or phosphorus values were seen.