Strontium ranelate and alendronate have differing effects on distal tibia bone microstructure in women with osteoporosis.
The structural basis of the antifracture efficacy of strontium ranelate and alendronate is incompletely understood. We compared the effects of strontium ranelate and alendronate on distal tibia microstructure over 2 years using HR-pQCT. In this pre-planned, interim, intention-to-treat analysis at 12 months, 88 osteoporotic postmenopausal women (mean age 63.7 +/- 7.4) were randomized to strontium ranelate 2 g/day or alendronate 70 mg/week in a double-placebo design. Primary endpoints were changes in microstructure. Secondary endpoints included lumbar and hip areal bone mineral density (aBMD), and bone turnover markers. This trial is registered with http://www.controlled-trials.com, number ISRCTN82719233. Baseline characteristics of the two groups were similar. Treatment with strontium ranelate was associated with increases in mean cortical thickness (CTh, 5.3%), cortical area (4.9%) and trabecular density (2.1%) (all P < 0.001, except cortical area P = 0.013). No significant changes were observed with alendronate. Between-group differences in favor of strontium ranelate were observed for CTh, cortical area, BV/TV and trabecular density (P = 0.045, 0.041, 0.048 and 0.035, respectively). aBMD increased to a similar extent with strontium ranelate and alendronate at the spine (5.7% versus 5.1%, respectively) and total hip (3.3% versus 2.2%, respectively). No significant changes were observed in remodeling markers with strontium ranelate, while suppression was observed with alendronate. Within the methodological constraints of HR-pQCT through its possible sensitivity to X-ray attenuation of different minerals, strontium ranelate had greater effects than alendronate on distal tibia cortical thickness and trabecular volumetric density.
Rizzoli
René
R
Division of Bone Diseases, Department of Rehabilitation and Geriatrics, Geneva University Hospitals and Faculty of Medicine, 1211, Geneva 14, Switzerland. Rene.Rizzoli@unige.ch
Laroche
Michel
M
Krieg
Marc-Antoine
MA
Frieling
Isolde
I
Thomas
Thierry
T
Delmas
Pierre
P
Felsenberg
Dieter
D
D019386:Alendronate / Q000627:therapeutic use*; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D050723:Fractures, Bone / Q000517:prevention & control; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008875:Middle Aged; D009942:Organometallic Compounds / Q000627:therapeutic use*; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D013131:Spine / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D013876:Thiophenes / Q000627:therapeutic use*; D013977:Tibia / Q000187:drug effects* / Q000473:pathology; D014057:Tomography, X-Ray Computed
D050071:Bone Density Conservation Agents; D009942:Organometallic Compounds; D013876:Thiophenes; C081587:strontium ranelate; D019386:Alendronate