Longterm effect of intermittent cyclical etidronate therapy on corticosteroid-induced osteoporosis in Japanese patients with connective tissue disease: 7-year followup.

Objective: To determine the efficacy and safety of intermittent cyclical etidronate therapy of up to 7 years for corticosteroid-induced osteoporosis.

Methods: One hundred two Japanese patients who originally participated in a 3-year prospective randomized study were enrolled into an open-label followup study. All patients had received > 7.5 mg of prednisolone daily for at least 90 days before entry into the original study and were randomly assigned to 2 treatment arms: E, those receiving etidronate disodium (200 mg per day) for 2 weeks together with 3.0 g of calcium lactate and 0.75 microg of alphacalcidol daily; and C, controls receiving only the latter. Endpoints included changes from baseline in bone mineral density (BMD) of the lumbar spine and the rate of new vertebral fractures.

Results: The mean (+/- SD) lumbar spine BMD had increased by 5.9% +/- 8.8% (p = 0.00007) and 2.2% +/- 5.8% (p = 0.013) from baseline after 7 years in groups E and C, respectively. This improvement in BMD in group E was significantly better than in group C (p = 0.02). The frequency of new vertebral fractures was lower in group E, resulting in reduction of the risk of such new fractures by 67% at year 7 (odds ratio 3.000; 95% confidence interval, 0.604 14.90; p = 0.18). There were no severe adverse events in group E during our study.

Conclusion: Our results indicate that longterm (up to 7 years) intermittent cyclical etidronate therapy is safe and effective for prevention and treatment of corticosteroid-induced osteoporosis in patients with connective tissue diseases.