Clinical Utility of Using Lumbar Spine Trabecular Bone Score to Adjust Fracture Probability: The Manitoba BMD Cohort

Abstract

Decreased lumbar spine trabecular bone score (TBS), a dual-energy X-ray absorptiometry (DXA)-derived image texture measurement, is a risk factor for major osteoporotic fracture (MOF) and hip fracture (HF) independent of 10-year fracture probability estimated using FRAX. We determined how often applying the TBS adjustment to fracture probability altered treatment qualification. Using a population-based registry containing all clinical DXA results for Manitoba, Canada, we identified 34,316 women with baseline spine and hip DXA, FRAX-based fracture probability measurements (computed with femoral neck bone mineral density), lumbar spine TBS, and minimum 5 years of observation (mean 8.7 years). Population-based health services data were used to identify incident non-traumatic MOF and HF in 3503 and 945 women, respectively. Baseline MOF and HF probabilities were estimated using FRAX before and after applying the TBS adjustment. Risk recategorization was assessed using net reclassification improvement (NRI) for individual FRAX-based intervention criteria and three national clinical practice guidelines (CPGs) (US National Osteoporosis Foundation, Osteoporosis Canada, and UK National Osteoporosis Guideline Group). Overall, proportions of women reclassified with the TBS adjustment to FRAX were small (less than 5%) with more than 90% of the reclassification occurring close to the intervention threshold. For women close to an intervention cut-off reclassification, rates ranged from 9.0% to 17.9% and were <1% otherwise. There was a small but significant improvement in overall NRI for all individual FRAX-based intervention criteria (range 0.007 to 0.018) and all three national CPGs (range 0.008 to 0.011). NRI was larger in women below age 65 years (up to 0.056 for hip fracture). In summary, a small but significant improvement in MOF and HF risk assessment was found by using lumbar spine TBS to adjust FRAX probability. An improvement in risk reclassification was observed for CPGs from three different countries, with almost all of the benefit found in individuals close to an intervention threshold. © 2017 American Society for Bone and Mineral Research. © 2017 American Society for Bone and Mineral Research.

Combining Frailty and Trabecular Bone Score Did Not Improve Predictive Accuracy in Risk of Major Osteoporotic Fractures

“…This is in line with some other publications that investigated the relationship between FRAX and TBS . For example, per‐SD increase in FRAX was found to have a HR rising from 1.70 to 1.76 after adjusting for TBS and adding TBS to FRAX yielded a small but significant improvement in overall NRI ranging from 0.7% to 1.8% when compared with FRAX alone . However, another study revealed that although TBS was significantly associated with MOF risk independent of FRAX, there was no significant improvement of discrimination between FRAX adjusted for TBS and FRAX alone .…”

“…Findings from observational studies have shown that TBS as a risk‐assessment tool is significantly related to risks of osteoporotic fractures independently of BMD and age . Results from some studies also reported FRAX (Fracture Risk Assessment Tool) in combination with TBS could improve its predictive accuracy for fracture risk, although the improvement was small or nonsignificant …”

Do Additional Clinical Risk Factors Improve the Performance of Fracture Risk Assessment Tool (FRAX) Among Postmenopausal Women? Findings From the Women's Health Initiative Observational Study and Clinical Trials

“…Limitations of this study include lack of information about other potential risk factors, including bone microarchitecture (eg, cortical porosity), trabecular bone score, hip axis length, vertebral imaging, bone turnover marker levels, and objective measures of physical function. In previous studies, two DXA‐derived measures (hip axis length and the trabecular bone score adjustment to FRAX) each provided improvement in net reclassification compared with the FRAX model alone. A study of Japanese women aged ≥40 years showed improvement in risk reclassification for the FRAX with trabecular bone score compared with the FRAX model alone .…”

Comparison of Methods for Improving Fracture Risk Assessment in Diabetes: The Manitoba BMD Registry

“…Among the clinically applicable techniques developed for bone quality assessment, trabecular bone score (TBS) has been the most extensively studied . TBS can help enhance fracture prediction when used in conjunction with FRAX probability estimated with BMD . TBS measurements were performed in the Bone Disease Unit at the University of Lausanne, Switzerland (TBS iNsight Software, Version 2.1, Med‐Imaps, Merignac, France), using anonymized spine DXA files to ensure blinding of the Swiss investigators to all clinical parameters and outcomes.…”

“…(21,22) TBS can help enhance fracture prediction when used in conjunction with FRAX probability estimated with BMD. (23) TBS measurements were performed in the Bone Disease Unit at the University of Lausanne, Switzerland (TBS iNsight Software, Version 2.1, Med-Imaps, Merignac, France), using anonymized spine DXA files to ensure blinding of the Swiss investigators to all clinical parameters and outcomes. We excluded women with BMI outside the range of 15 to 37 kg/m2 as recommended by the TBS manufacturer.…”