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/cm2 per year of follow-up (95% confidence interval 0.017-0.032 g/cm2). 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.