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M Schoeb 1, F Malgo 1, J J M Peeters 1, E M Winter 1, S E Papapoulos 1, N M Appelman-Dijkstra 2
Osteoporos Int. 2020 Sep;31(9):1683-1690. doi: 10.1007/s00198-020-05375-3. Epub 2020 Apr 8.
PMID: 32270252 PMCID: PMC7423791 DOI: 10.1007/s00198-020-05375-3
Effects on bone material properties of two-year antiosteoporotic treatment were assessed using in vivo impact microindentation (IMI) in patients with low bone mineral density (BMD) values. Antiresorptive treatment, in contrast to vitamin D ± calcium treatment alone, induced BMD-independent increases in bone material strength index, measured by IMI, the magnitude of which depended on pretreatment values.
Introduction: Bone material strength index (BMSi), measured by IMI in vivo, is reduced in patients with fragility fractures, but there is no information about changes in values during long-term therapy. In the present study, we assessed changes in BMSi in patients receiving antiosteoporotic treatments for periods longer than 12 months.
Methods: We included treatment-naive patients with low bone mass who had a BMSi measurement with OsteoProbe® at presentation and consented to a repeat measurement after treatment.
Results: We studied 54 patients (34 women), median age 58 years, of whom 30 were treated with bisphosphonates or denosumab (treatment group) and 24 with vitamin D ± calcium alone (control group). There were no differences in clinical characteristics between the two groups with the exception of a higher number of previous fragility fractures in the treatment group. Baseline hip BMD and BMSi values were lower in the treatment group. After 23.1 ± 6.6 months, BMSi increased significantly in the treatment group (82.4 ± 4.3 vs 79.3 ± 4.1; p < 0.001), but did not change in the control group (81.5 ± 5.2 vs 82.2 ± 4.1; p = 0.35). Changes in BMSi with antiresorptives were inversely related with baseline values (r = – 0.43; p = 0.02) but not with changes in BMD. Two patients in the control group with large decreases in BMSi values sustained incident fractures.
Conclusion: In patients at increased fracture risk, antiresorptive treatments induced BMD-independent increases in BMSi values, the magnitude of which depended on pretreatment values.
Keywords: Bisphosphonates; Bone material strength index (BMSi); Denosumab; Fragility fracture; Impact microindentation; Reference point indentation.