Cost-effectiveness analysis of drugs for osteoporosis treatment in elderly Japanese women at high risk of fragility fractures: comparison of denosumab and weekly alendronate

Abstract

In Japan's super-aged society, the prevention and treatment of osteoporosis are a critical issue with implications for the medical economy. This study's purpose was to clarify the cost-effectiveness of osteoporosis treatment with denosumab versus weekly alendronate for elderly Japanese women at high risk of fragility fractures. A Markov model was used for simulation analysis. The modeled population was 75-year-old Japanese women with a bone mineral density (BMD) of 65% of the young adult mean (YAM) (T-score, - 2.87) and a history of previous vertebral body fracture. The simulation model was repeated until patient age reached 100years or death. Analysis was performed from the societal perspective. Costs and epidemiological data were derived from previous studies. The incremental cost-effectiveness ratio (ICER) was calculated from the simulation. We compared the ICER with willingness-to-pay. Additional analyses were performed with different combinations of age and BMD. Sensitivity analysis verified the robustness of the analysis. For the modeled population, the ICER of denosumab versus alendronate treatment was estimated at US$40,241/quality-adjusted life year (QALY). The ICER of denosumab for 80-year-old women whose BMD was 60% of YAM was estimated at US$22,469/QALY. Assuming willingness-to-pay as US$50,000/QALY, denosumab treatment for 75-year-old Japanese women with a BMD of 65% of YAM and a history of previous vertebral body fracture was cost-effective compared with alendronate treatment. Among over 75years of age, denosumab treatment might be more cost-effective than alendronate for patients with a BMD of 65% of YAM or lower.