Introduction and hypothesis
Over half of all fractures among post-menopausal women occur in those who do not have osteoporosis by bone density criteria.
Measurement of bone turnover may cost-effectively identify a subset of women with T-score >−2.5 for whom anti-resorptive drug
therapy is cost-effective.
Methods
Using a Markov model, we estimated the cost per quality adjusted life year (QALY) for five years of oral bisphosphonate compared
to no drug therapy for osteopenic post-menopausal women aged 60 to 80 years with a high (top quartile) or low (bottom 3 quartiles)
level of a bone turnover marker.
Results
For women with high bone turnover, the cost per QALY gained with alendronate compared to no drug therapy among women aged
70 years with T-scores of −2.0 or −1.5 were 58,000 and58,000 and 80,000 (U.S. 2004 dollars), respectively. If bisphosphonates therapy
also reduced the risk of non-vertebral fractures by 20% among osteopenic women with high bone turnover, then the costs per
QALY gained were 34,000 and34,000 and 50,000 for women age 70 with high bone turnover and T-scores of −2.0 and −1.5, respectively.
Conclusion
Measurement of bone turnover markers has the potential to identify a subset of post-menopausal women without osteoporosis
by bone density criteria for whom bisphosphonate therapy to prevent fracture is cost-effective. The size of that subset highly
depends on the assumed efficacy of bisphosphonates for fracture risk reduction among women with both a T-score >−2.5 and high
bone turnover and the cost of bisphosphonate treatment.
Keywords Bisphosphonates - Bone turnover - Cost-effectiveness - Non-vertebral fracture - Vertebral fracture