Which Bone Agent Is Best in High-risk Osteoporosis?
By Eric S. Schned, MD
Background: Bisphosphonate therapy is the current standard of care for the prevention and treatment of glucocorticoid-induced osteoporosis (GIO). Studies of anabolic therapy in patients who are receiving long-term glucocorticoids (GCs) and are at high risk for fracture are lacking.
Methods: In an 18-month randomized, double-blind, controlled trial, we compared teriparatide with alendronate in 428 women and men with osteoporosis (ages 22 to 89) who had received GCs for at least three months (prednisone equivalent, 5 mg daily or more). A total of 214 patients received 20 μg of teriparatide once daily, and 214 received 10 mg of alendronate once daily. The primary outcome was the change in bone mineral density at the lumbar spine (LS). Secondary outcomes included changes in bone mineral density at the total hip and in markers of bone turnover, the time to changes in bone mineral density, the incidence of fractures, and safety.
Results: At the last measurement, the mean (±SE) bone mineral density at the LS had increased more in the teriparatide group than in the alendronate group (7.2±0.7% versus 3.4±0.7%, p<0.001). A significant difference between the groups was reached by six months (p<0.001). At 12 months, bone mineral density at the total hip had increased more in the teriparatide group. Fewer new vertebral fractures occurred in the teriparatide group than in the alendronate group (0.6% versus 6.1%, p=0.004); the incidence of nonvertebral fractures was similar in the two groups (5.6% versus 3.7%, p=0.36). Significantly more patients in the teriparatide group had at least one elevated measure of serum calcium.
Conclusions: Among patients with osteoporosis who were at high risk for fracture, bone mineral density increased more in patients receiving teriparatide than in those receiving alendronate.
Rheumatologists know intimately the hazards of long-term GC therapy. GIO and resultant fractures are especially vexing problems since some patients in whom we use GCs are already at high risk for these complications. These patients include postmenopausal women with long-standing RA or lupus and elderly patients with polymyalgia rheumatica (PMR) and giant cell arteritis (GCA).
Bisphosphonate therapy is the current standard of care for patients who already have—or are at risk for developing—GIO.1 Bisphosphonates act primarily on bone resorption, however, while teriparatide directly stimulates osteogenesis and inhibits osteoblast apoptosis, two key mechanisms in bone affected by GCs.2 These actions make teriparatide a good candidate for treating or preventing GIO.