Effect of intermittent cyclical disodium etidronate therapy on bone mineral density in men with vertebral fractures

Objectives: to investigate the effects of oral intermittent cyclical etidronate therapy on bone mineral density (BMD) in men with idiopathic vertebral osteoporosis. Design: consecutive case series. Setting: regional specialist clinic for metabolic bone disease. Subjects: 42 men aged 35-81 (median 60.5) with established vertebral crush fractures and back pain, in whom secondary causes of osteoporosis had been excluded. Intervention: repeated cycles of treatment with oral disodium etidronate 400 mg daily for 14 days followed by oral calcium 500 mg as citrate daily for 76 days. Outcome measures: BMD measurement of the lumbar spine and femoral neck by dual energy x-ray absorptiometry at 6-12-month intervals; bone biochemistry (serum calcium, phosphate, alkaline phosphatase and urine calcium/creatinine and hydroxyproline/creatinine ratios) at 6-month intervals. Results: all 42 men have been treated for more than 18 months, and 35 of them for more than 24 months. Median follow-up for the group as a whole is 31 months (range 18-45). The treatment was well tolerated. BMD at the lumbar spine increased by a mean of 0.024 g/cm(2) per year of follow-up (95% confidence interval 0.017-0.032 g/cm(2)). This is equivalent to an average annual rate of change of 3.2% of baseline values. There was a small, non-significant rise in mean BMD at the hip equivalent to 0.7% of baseline values per year. Serum alkaline phosphatase tended to fall in the first 6 months of treatment, returning to baseline values at 2 years. Serum calcium and phosphate were unchanged and no decrease in urinary calcium/creatinine ratio or hydroxyproline/creatinine ratio was seen. Conclusions: intermittent cyclical etidronate therapy increased lumbar spine BMD over a 2-year period in an unselected group of men with osteoporotic vertebral fractures. This treatment warrants further evaluation in a randomized controlled trial.