1-Alpha-hydroxy vitamin D in dialysis bone disease: radiological changes after 6 and 12 months of treatment.

Biochemical, radiological and histological indicators of dialysis bone disease were studied before, 6 months (58 patients) and 12 months (48 patients) after starting treatment with 1 alpha-OH D3. Radiographic healing of subperiosteal erosions was seen after 6 months in 60% and after 12 months in 77% of affected patients. Radiographic improvement, however, was not significantly related to reductions in resorptive surfaces seen on quantitative bone histology, nor to changes in plasma concentrations of immunoreactive parathyroid hormone. Metastatic calcification appeared or increased in 43% of patients after 6 months and 52% after 12 months. Periosteal new bone developed or increased in 14% of patients after 6 months and 17% after 12 months. Both metastatic calcification and periosteal new bone formation were associated with high plasma phosphate concentrations, but not with plasma calcium, alkaline phosphatase or parathyroid hormone concentrations. Treatment with 1 alpha-OH D3 produces radiological improvement in the majority of patients with dialysis bone disease, but the lack of correlation with histological changes confirms the need for regular radiographic examination. Metastatic calcification and periosteal new bone formation probably represent toxicity of 1 alpha-OH D3 but may be minimised by phosphate restriction.