In people with osteoporosis due to steroid medications, a once-yearly infusion of zoledronic acid increased bone mass better than oral daily risedronate did, a new study found. The results will be discussed Sunday, June 15, at The Endocrine Society’s 90th Annual Meeting in San Francisco.

“The study showed that zoledronic acid is significantly more effective than risedronate in preventing and treating bone loss associated with glucocorticoid use,” said the multicenter study’s lead author, David Reid, MD, of the University of Aberdeen in the United Kingdom.

The intravenous drug, which has the brand name Reclast in the United States, is already approved for treatment of postmenopausal osteoporosis and another bone disorder, Paget’s disease.

This new study evaluated how well zoledronic acid works in the prevention and treatment of glucocorticoid-induced osteoporosis, compared with risedronate (Actonel). Glucocorticoids are steroids, including prednisone, that doctors use to treat inflammatory conditions, such as arthritis or asthma. These medications often cause bone loss, according to Reid. Up to 50 percent of patients receiving long-term therapy with these steroids are at increased risk of fracture due to osteoporosis, and 9 million people worldwide have glucocorticoid-induced osteoporosis, he said.

Their study included 833 patients (265 men and 568 women) who were receiving high-dose steroid therapy. Two groups were studied: one for prevention and one for treatment of osteoporosis.

The treatment group had 545 patients who were at high risk of steroid-caused osteoporosis because their steroid therapy had lasted more than 3 months. The prevention group included 288 patients who had received steroids for 3 months or less. In each group, patients were randomly assigned to receive either zoledronic acid or an inert placebo infusion at the start of the study, followed by 12 months of a daily placebo pill or oral risedronate, respectively.

The main goal of the study was to evaluate the percent change in bone mineral density in the spine of the lower back (lumbar spine) after 12 months of treatment, as shown on DXA bone density scans. Secondary aims included comparing the 12-month percent change in bone density in the hip and top of the thigh bone (femoral neck).

In the treatment group, lumbar spine bone density increased by 4.1 percent in patients receiving zoledronic acid compared with 2.7 percent in those taking risedronate, the authors found. Zoledronic acid also increased spine bone density in the prevention group more than risedronate did (2.6 versus 0.6 percent), Reid said. It also reportedly was more effective than the oral drug at increasing bone density at the other sites in both the treatment and prevention groups.

Adverse effects were similar with both drugs except for a higher incidence of short-lasting fever and muscle pain during the first three days of zoledronic acid therapy, Reid said.

Novartis, which makes Reclast, funded the study. Reid said he receives consulting and lecture fees from Novartis.

Researchers from the United Kingdom, United States, Belgium, France, Switzerland and Australia conducted this study.

# # #

Founded in 1916, The Endocrine Society is the world's oldest, largest, and most active organization devoted to research on hormones and the clinical practice of endocrinology. Today, The Endocrine Society's membership consists of over 14,000 scientists, physicians, educators, nurses and students in more than 80 countries. Together, these members represent all basic, applied, and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Md. To learn more about the Society, and the field of endocrinology, visit our web site at www.endo-society.org.