Trabecular bone score less useful bone strength biomarker than BMD for older adults
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Antiresorptive medications such as oral bisphosphonates have a minimal effect on change in lumbar spine trabecular bone score among older adults, according to a study published in The Journal of Bone and Mineral Research.
In findings from adults aged 40 years and older who underwent two DXA scans within a 5-year period, tissue thickness change, acquisition mode change, weight change and spine percent fat change were the factors most associated with change in trabecular bone score. The use of an osteoporosis medication had little effect on trabecular bone score change, but was the most significant variable associated with change in spine and total hip bone mineral density.
“This large registry-based analysis was able to identify technical and clinical factors associated with finding a significant change in spine trabecular bone score and contrast this with significant changes in spine BMD and total hip BMD,” William D. Leslie, MD, MSc, FRCPC, professor of medicine and radiology at the University of Manitoba in Winnipeg, Canada, and colleagues wrote. “Some of these results are expected given the inability of antiresorptive therapies to alter trabecular bone structure, rendering trabecular bone score a relatively insensitive biomarker for response assessment as reported previously. Thus, although there was a dose response between medication exposure and change in trabecular bone score, this was much less than that found with BMD.”
Researchers obtained data from the Manitoba Density Program of all adults aged 40 years and older who underwent two fan-beam DXA scans performed on the same scanner within a 5-year period. Lumbar spine trabecular bone score exceeding the 95% least significant change was the primary outcome. Use of osteoporotic medication between the two scans was defined as low if the medication persistence ratio was less than 0.5, moderate if the ratio was between 0.5 and 0.79, and high if the ratio was 0.8 or higher. Other clinical factors and demographics were obtained from the DXA scan registry.
The study included 11,643 adults (mean age, 65.3 years; 93.6% women). The first and second DXA measurements were highly correlated for spine trabecular bone score (r = 0.79), spine BMD (r = 0.92) and total hip BMD (r = 0.85).
Of the cohort, 60% used an osteoporosis medication between the two scans, and 27% of medication users had a high medication persistence ratio. Oral bisphosphonates accounted for 78.3% of medication use. Of adults who did not use a medication, 24.1% had a decrease in spine BMD and 37.8% had a decrease in total hip BMD compared with 16.9% who had a trabecular bone score decrease. Similarly, more adults with a high medication persistence ratio had an increase in spine BMD (33.6%) and total hip BMD (38.6%) compared with trabecular bone score (10.5%).
Each 1 cm increase in spine tissue thickness (OR = 15.5; 95% CI, 13.5-17.8) and change to a thinner acquisition mode (OR = 8.56; 95% CI, 5.51-13.3) were the factors most strongly associated with greater odds for trabecular bone score decrease. Neither variable was associated with spine BMD change and only increase tissue thickness was associated with total hip BMD loss. Adults who used glucocorticoids (OR = 1.33; 95% CI, 1.04-1.7) and aromatase inhibitors (OR = 1.6; 95% CI, 1.21-2.12) had higher odds for trabecular bone score loss than nonusers, but the ORs between use of those medications and loss of spine and total hip BMD were greater.
“Change in trabecular bone score should be interpreted in light of the limitations and technical factors identified in this study,” the researchers wrote. “Our findings suggest a limited role, if any, for using trabecular bone score change in untreated individuals or for monitoring response to antiresorptive treatment in routine clinical practice with the current version of the trabecular bone score algorithm.”
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