Cost-effectiveness of weekly gastro-resistant risedronate 35 mg, compared with weekly alendronate 70 mg tablets, in the treatment of postmenopausal osteoporosis in Spain

Aim: To estimate the cost-effectiveness of treating postmenopausal osteoporosis (PMO) with weekly gastro-resistant risedronate 35 mg gastro-resistant tablets (RIS-GR), compared with weekly alendronate 70 mg tablets (ALN) in Spain. Methods: A probabilistic analysis (second-order Monte Carlo simulation) was performed with a time horizon of 5 years, from the perspective of the Spanish National Health System. The bone fracture probabilities were obtained from a cohort study of 3614 women from USA with PMO treated with RIS-GR (1807) or ALN (1807) (Thomasius, 2022). The pharmacological cost and the cost of fractures were obtained from Spanish sources (euro 2022). The utilities of patients with and without fracture (quality adjusted life years [QALYs]) were obtained from the medical literature. Results: Compared with ALN, treatment with RIS-GR can avoid 79 fractures (between 75 and 82) every 1000 patients treated, and 0.0119 QALYs would be gained (between 0.0098 and 0.0140) per patient. Additionally, GR-RIS would generate a cost saving per patient of euro1994 (euro1437-2904) with a probability of 99.7%. The scenario analyses confirmed the stability of the base case results. Conclusion: According to this study, RIS-GR would be the dominant treatment (lower costs with QALY gain) compared with ALN.