VIENNA — Alendronate is markedly more effective than 1-hydroxyvitamin D3 (alfacalcidol) as prophylaxis against glucocorticoid-induced osteoporosis, Johannes W.J. Bijlsma, M.D., Ph.D., said at the annual European congress of rheumatology.
He reported on 200 patients—40% men, the rest postmenopausal women—in an 18-month randomized double- blind 23-center Dutch trial that was sponsored by the Netherlands Health Council.
Participants had various rheumatic diseases for which they were placed on systemic steroids at a mean starting dose of 23 mg/day of prednisolone or its equivalent. Over 18 months their cumulative dose was nearly 6 g.
Patients were randomized at the outset of steroid therapy to 10 mg/day of alendronate plus placebo or 1 mcg/day of alfacalcidol, an activated vitamin D, plus placebo.
The primary study end point was change in lumbar spine bone mineral density over the 18 months. It increased by 2.3% in the alendronate group and decreased by 1.9% in the alfacalcidol group, for a net 4.2% difference between the regimens.
Similarly, total hip bone mineral density increased by 0.7% in the alendronate group, while declining by 2.5% with alfacalcidol, said Dr. Bijlsma, professor and head of the department of rheumatology and clinical immunology at University Medical Center, Utrecht, the Netherlands.
Three asymptomatic vertebral fractures occurred in three patients in the alendronate group, compared with 13 vertebral fractures in eight patients in the alfacalcidol group; 5 of them were in three patients who were symptomatic.
Glucocorticoid-induced osteoporosis is an enormous problem.
In various epidemiologic studies, 0.5%–1.7% of women over age 55 are on prolonged systemic steroid therapy, and 50% develop osteoporosis. One-third experience vertebral fractures. Marked trabecular bone loss, mainly due to reduced bone formation, is observed within the first 6 months of steroid therapy.
Bisphosphonates are known to protect against steroid-induced osteoporosis. Alfacalcidol was deemed worth studying as an alternative because activated vitamin D stimulates osteoblasts, thereby encouraging bone formation, Dr. Bijlsma explained at the meeting, sponsored by the European League Against Rheumatism.