Vertebral fractures in postmenopausal women (<65 years of age) with osteoporosis can lead to acute and chronic back pain, loss of weight, reduced pulmonary function, back related disability, depression, and a sustained decrease in quality of life. Early fractures occurring within the first 10 years after menopause are especially troublesome since they are a major risk factor for further additional fractures.

Strontium ranelate is an anti-osteoporotic treatment with a unique mode of action which reduces bone resorption while promoting continued bone formation [Marie PJ et al. Calcif Tissue Int 2001]. It has been shown to be effective in reducing the risk of vertebral fractures in two phase 3 studies. In the Spinal Osteoporosis Therapeutic Intervention (SPOTI) study of 1,649 postmenopausal women (mean age 69.4±7.2) with osteoporosis, strontium ranelate 2g/day produced a risk reduction for vertebral fracture of 49% in the first year and 41% over 3 years [Meunier PJ et al. N Engl J Med 2004]. The Treatment of Peripheral Osteoporosis (TROPOS) study was designed to examine the effect of strontium ranelate on non-vertebral fractures in postmenopausal women with osteoporosis (mean age 76.7±8). Three thousand six hundred and forty (3,640) of the 5,091 patients had spine X-rays, which showed a risk reduction of 45% at 1 year and 39% over 3 years [Reginster JY et al. J Clin Endocrinol Metab 2005].

The objective of this study, presented at EULAR by Prof. Roux, René Descartes University, Paris, was to assess the efficacy of strontium ranelate in the reduction of vertebral fracture risk in women between the ages of 50 and 65 using data from the SPOTI study.

Women in this database (168 treated with strontium ranelate; 185 in the placebo group) had a mean age of 60.0±3.5 years, lumbar bone mineral density (BMD) T-score of −3.6±1.1, and a femoral neck BMD T-score of −2.5±0.8; 80.5% of the patients had a prevalent vertebral fracture and 23.0% had a prevalent non-vertebral fracture.

Treatment with strontium ranelate, reduced the relative risk of vertebral fractures by 47% over 3 years, and by 40% over 4 years (p=0.006). The incidence of vertebral fractures over 3 years was 16.9% in the strontium ranelate treated group vs 29.6% in the placebo treated group (Figure 1).

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Figure 1:

Reduction of Vertebral Fracture Risk in Younger Patients.

The reduction in the risk of vertebral fracture was paralleled by a significant increase (14.6%; p<0.001) in the relative change from baseline of lumbar BMD after 3 years, and by 7.5% in the relative change from baseline of femoral neck BMD vs placebo. Nausea, diarrhea, headache, and dermatitis were the most reported adverse events, none of which were significantly different from placebo.

Strontium ranelate significantly reduces vertebral fractures in postmenopausal women <65 years of age with severe osteoporosis.