Bisphosphonates for Osteoporosis Treatment: A Cost-Effectiveness Analysis in Vietnamese Woman

• Published in: Value in health 2017-10, Vol.20 (9), p.A535
• Main Authors: Pham, NH, Nguyen, TB, Le, HP, Pham, DT, Ho-Pham, LT, Duong, TD, Nguyen, TV
• Format: Article
• Language: English
• Subjects: Age; Alendronate; Alendronic acid; Bisphosphonates; Bone diseases; Cost analysis; Fractured hips; Health care expenditures; Hip; Medical treatment; Osteoporosis; Patients; Post-menopause; Postmenopausal women; Quality adjusted life years; Sensitivity analysis; Vertebrae; Willingness to pay; Zoledronic acid
• ISSN: 1098-3015; 1524-4733
• DOI: 10.1016/j.jval.2017.08.773

OBJECTIVES: Osteoporosis affects approximately 30% of postmenopausal women in Vietnam. Bisphosphonates (eg alendronate and zoledronate) are considered first-line treatment. Vietnam is classified as a lower middle-income country, and the cost-effectiveness of bisphosphonates is not clear. In this study we sought to analyze the cost-effectiveness of bisphosphonates in the treatment of patients who are diagnised with osteoporosis. METHODS: The study was based on a cohort of women aged 50+ years who were participants of the Vietnam Osteoporosis Study. A Markov model was constructed for the cohort, with 3 treatment options being compared: no treatment, a 5-year course with oral alendronate 70 mg/week, and a 5-year course of zoledronate 5 mg/year. The entire cohort entered the model in the 'osteoporosis' state, and then transitioned to other health states including 'hip fracture', 'vertebral fracture', 'post-hip fracture', and 'post-vertebral fracture* until death or age 100. A willingness-to-pay (WTP) threshold of 3 times the GDP per capita ($6,108 in 2015) was applied to determine cost-effectiveness. Unit costs were derived from national database, and all costs were adjusted to 2015 US dollars. RESULTS: For all age groups, zoledronate offered the highest QALYs gain and was the most cost-effective treatment at the chosen WTP threshold. The incremental cost-effectiveness ratio (ICER) of zoledronate was lowest for patients aged 65 years ($1,812/ QALY) compared to other age groups. In one-way sensitivity analysis, the cost of post-fracture and treatment adherence had the highest impact on the ICERs, but zoledronate remained the best option under the WTP threshold. In probabilistic sensitivity analysis, the probability of being the most cost-effective treatment for zoledronate ranged from 68% to 98%, depending on patients' age. CONCLUSIONS: At a willingness-to-pay of $6,108/QALY, zoledronate was the most cost-effective osteoporosis therapy for postmenopausal women aged ≥50 years old in Vietnam.