Strontium ranelate has higher effects than alendronate on bone microarchitecture in postmenopausal osteoporosis
Strontium ranelate and alendronate are antiosteoporotic agents with proven antifracture efficacy against vertebral and nonvertebral fractures (including hip). Whereas alendronate is a bone resorption inhibitor, strontium ranelate increases bone formation and decreases bone resorption. For the first time, a study [1] noninvasively evaluated and compared, in a head-to-head trial, the effects of strontium ranelate and alendronate on bone microstructure, a component of bone quality, and hence of bone strength, in osteoporotic women.Eighty-eight women ≥50 years old with postmenopausal osteoporosis were randomized to strontium ranelate 2g/day or alendronate 70 mg/week for 2 years. Microstructure of weight-bearing bone distal tibia was assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT, Xtreme CT, Scanco Medical) after 3, 6, 12, 18, and 24 months of treatment. A preplanned interim statistical analysis was performed after 1 year in the intention-to-treat population (ie, patients with a baseline and post-baseline assessable HR-pQCT examination, n=85). The primary end point was HR-pQCT variables relative changes from baseline, secondary end points included lumbar spine and hip areal BMD and bone turnover markers.
Baseline characteristics (age, lumbar and hip T-Score) were similar in both groups. After 1 year of treatment, mean increases were +5.3% (P<0.001) for cortical thickness, +2.0% (P=0.002) for bone volume (BV/TV) and +2.1% (P=0.002) for trabecular density in the strontium ranelate group, whereas there was no significant change in the alendronate group, with thus a significant between-group difference in favour of strontium ranelate (P=0.045, P=0.048 and P=0.035, for cortical thickness, BV/TV and trabecular density, respectively). The increase in C.Th with strontium ranelate was +2.9% at 3 months versus baseline (P<0.001) and was greater than in the alendronate group (P=0.012).
In conclusion, strontium ranelate had significantly higher effects than alendronate on both cortical and trabecular microstructure, in women with postmenopausal osteoporosis after one year of treatment. This effect is significant within 3 months of treatment.
- Rizzoli R, Laroche M, Krieg MA, et al. Rheumatol Int. 2010;30(10):1341-1348.
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