Randomized Trial of Effect of Cyclical Etidronate in the Prevention of Corticosteroid-Induced Bone Loss

Abstract

Osteoporosis is a well-recognized adverse effect of corticosteroid therapy. This study aimed to investigate the effect of etidronate, intermittent cyclical therapy, in the prevention of corticosteroid-induced bone loss. Patients with various medical conditions starting high-dose corticosteroid therapy were enrolled in the study. The treatment had to be expected to continue for at least 12 months with the initial 90 days at a mean daily dose of at least 7.5 mg of prednisone, with subsequent treatment of at least 2.5 mg/day. One hundred seventeen patients were randomly assigned oral etidronate 400 mg/day, or placebo, for 14 days, followed by 76 days of oral calcium carbonate (500 mg elemental calcium), cycled over 12 months. The primary outcome measure was the difference in percent change from baseline in bone mineral density of the lumbar spine between the groups at the end of year 1. Secondary measures included changes in femur bone density and in biochemical markers of bone remodeling. The mean (+/- SEM) lumbar spine bone density changed 0.30 +/- 0.61% and -2.79 +/- 0.63% in the etidronate and placebo groups, respectively. The mean difference between groups after 1 yr was 3.0 +/- 0.84% (P = 0.004). The changes in the femoral neck and great trochanter were not different between the groups. There was a decrease in pyridinium crosslinks, significant from baseline at both 6 and 12 months, in the etidronate group. Osteocalcin increased in the placebo group, and difference between groups was -25.07 +/- 14.89% (P = 0.032) and -34.68 +/- 19.77% (P = 0.051), at 6 and 12 months respectively. There was no significant difference between the groups in number of adverse experiences, including gastrointestinal disorders. Etidronate intermittent cyclical therapy prevents lumbar vertebral bone loss in patients starting high-dose corticosteroid therapy.