Treatment of Osteoporosis

Combining Bisphosphonates with Raloxifene to Treat Osteoporosis: A Review of the Evidence

Objective:

To evaluate published studies regarding the combination of a bisphosphonate and raloxifene in the treatment of osteoporosis.

Data Sources:

A MEDLINE search (1966–February 2006) was conducted using the search terms osteoporosis, alendronate, risedronate, ibandronate, raloxifene, bisphosphonate, treatment, and selective estrogen-receptor modulators.

Study Selection and Data Extraction:

Clinical trials examining the efficacy of bisphosphonate and raloxifene in the treatment of osteoporosis were reviewed. Two trials evaluated alendronate or clodronate plus raloxifene for the treatment of osteoporosis in postmenopausal women.

Data Synthesis:

The results demonstrated a significant increase in lumbar bone mineral density (BMD) and conflicting results in the femoral BMD. Fracture risk was not assessed in either study.

Conclusions:

Published trials assessed BMD rather than fracture risk and were limited by methodologic flaws. Due to insufficient clinical outcomes data, combining these antiresorptive treatments cannot be recommended.

Anti-resorptive therapy for the prevention of postmenopausal osteoporosis : when should treatment begin?

Osteoporosis is a condition associated with decreased bone strength and an increased fracture risk. It may be defined based on bone mineral density (BMD) with a T-score at the hip or spine of less than -2.5 standard deviations in young healthy individuals or from an osteoporotic fracture (i.e. a fracture occurring after low-energy trauma or no apparent trauma). Risk factors predisposing to fractures include: increasing age; female gender; low BMD; a prior fragility fracture; a family history of fragility fractures; low bodyweight; lack of estrogen in women (i.e. post menopause); corticosteroid use; smoking; a number of diseases; deficiency in calcium and vitamin D; an increased risk of falls (i.e. impaired vision); immobilization; and Caucasian race. The more risk factors that are present the higher the risk of fractures over the following 10 years. The need to initiate preventive therapy with anti-osteoporotic treatment increases steeply with the absolute fracture risk. Indications for referral for dual energy x-ray absorptiometry measurement of BMD include: age >65 years; age <65 years in postmenopausal women with any of the risk factors already mentioned; premature menopause (<45 years); prolonged amenorrhea (>1 year) in younger women; fragility fractures; and diseases or conditions known to lead to osteoporosis.Anti-resorptive therapies include calcium plus vitamin D, bisphosphonates (alendronate, etidronate, risedronate, ibandronate), selective estrogen receptor modulators (raloxifene), hormone replacement therapy, and calcitonin. Guidelines from several countries on when to initiate anti-resorptive therapy state that therapy may be started in patients with a prior fragility fracture (some guidelines state that in this situation no BMD measurements are necessary) or in patients with a T-score of less than -2.5 (some guidelines state that additional risk factors need to be present in this situation). Some guidelines state that anti-resorptive therapy may be initiated in patients with a T-score in the osteopenic range (from -1 to -2.5, i.e. not frank osteoporosis) in the presence of other risk factors. The cost effectiveness of anti-resorptive therapy increases with the absolute fracture risk. In some scenarios, treatment with bisphosphonates may be cost effective in a 50-year-old woman with an absolute hip fracture risk of >or=1.1% over the next 10 years.