[en] OBJECTIVE: To estimate the cost-effectiveness of strontium ranelate in the treatment of postmenopausal osteoporotic women aged over 75 years. MATERIALS AND METHODS: A validated Markov microsimulation model with a Belgian payer's perspective estimated the cost per quality-adjusted life-year (QALY) of a 3-year strontium ranelate treatment compared with no treatment and with the bisphosphonate risedronate. Data on the effect of both treatments on fracture risk were taken from the Cochrane Database of Systematic Reviews. Analyses were performed for postmenopausal women aged 75 and 80 years, either with a diagnosis of osteoporosis (i.e. bone mineral density T-score </=-2.5 SD) or with prevalent vertebral fractures (PVF). Parameter uncertainty was evaluated using both one-way and probabilistic sensitivity analyses. RESULTS: Strontium ranelate was dominant (i.e. more effective and less costly) versus risedronate for women with osteoporosis aged over 75 years and for women with PVF aged 80 years. The cost per QALY gained of strontium ranelate compared with risedronate at 75 years of age was euro11,435 for women with PVF. When compared with no treatment, the costs per QALY gained of strontium ranelate were euro15,588 and euro7,708 at 75 and 80 years of age for women with osteoporosis; the equivalent values were euro16,518 and euro6,015 for women with PVF. Probabilistic sensitivity analyses showed that strontium ranelate was generally more cost-effective than risedronate, in the range of 60% in all cases. CONCLUSION: The results of this study suggest that strontium ranelate is a cost-effective strategy, in a Belgian setting, for the treatment of postmenopausal osteoporotic women aged over 75 years.