Effect of cyclical therapy with phosphorus and etidronate on axial bone mineral density in postmenopausal osteoporotic women.

Forty seven women with postmenopausal osteoporosis and at least one but no more than four vertebral compression fractures received sequential and cyclical therapy with phosphorus and etidronate (p/etid). During the same 2-year period of observation, three other groups of patients received either sodium fluoride (n = 12), estrogen replacement therapy (n = 12), or vitamin D and calcium (Ca++) alone (n = 15). Axial bone mineral density (BMD) was measured by means of dual-photon absorptiometry. Lateral thoracic and lumbar spine radiographs were taken to assess fractures. Bone mineral density increased from baseline during p/etid therapy: Mean 15.7 +/- 1.6% (SD) (P less than 0.001). During the same time, the patients in the sodium fluoride group showed a comparable increase in their BMD from baseline: mean 15.7 +/- 1.1% (P less than 0.001). During the first year of therapy, patients in the estrogen replacement group had an increase in their BMD from baseline: mean: 4.6% +/- 1.1% (P less than 0.05). No change in BMD was seen in the control group that received vitamin D and Ca++ alone. No patient who received p/etid, sodium fluoride, or estrogen replacement therapy had any new vertebral compression fractures or height loss, whereas in the control group that received vitamin D and Ca++ alone 6 out of 15 had height loss and at least one new vertebral fracture (P less than 0.01). p/etid therapy increases BMD in women with postmenopausal osteoporosis comparable to sodium fluoride but without side effects or toxicity and stabilizes vertebral compression fractures.