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Published in: Osteoporosis International 3/2018

01-03-2018 | Original Article

Risk-equivalent T-score adjustment for using lumbar spine trabecular bone score (TBS): the Manitoba BMD registry

Authors: W. D. Leslie, E. Shevroja, H. Johansson, E. V. McCloskey, N. C. Harvey, J. A. Kanis, D. Hans

Published in: Osteoporosis International | Issue 3/2018

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Abstract

Summary

Lumbar spine trabecular bone score (TBS) can be used to modify the output from the fracture risk assessment tool, FRAX, to enhance fracture prediction. An alternative approach for using TBS in clinical practice, based upon an adjustment to the bone mineral density (BMD) T-score, may be helpful in regions where intervention guidelines and/or reimbursement are primarily based on BMD T-score.

Introduction

The aim of this study is to develop an approach for using TBS in clinical practice based upon a “risk-equivalent” adjustment to the BMD T-score.

Methods

We identified 45,185 women age 40 years and older with baseline spine and hip DXA, TBS, and FRAX probabilities including femoral neck BMD. Incident major osteoporotic fractures (MOF, n = 3925) were identified from population-based health services data (mean follow-up 7.4 years comprising 335,910 person-years). Cox proportional hazards models adjusted for age and BMI were first used to estimate the risk for MOF from BMD T-score alone, then after including TBS and a multiplicative age interaction term. From the parameter estimates, we developed a TBS offset to the BMD T-score based upon change in TBS that would give the same risk as a unit change in BMD T-score for the femoral neck, total hip, and lumbar spine.

Results

All BMD measurements, TBS, and the age interaction term independently predicted MOF (p < 0.001). Measures of risk stratification and model fit were improved for the TBS-adjusted BMD T-score versus the unadjusted BMD T-score (p < 0.001). There was a high level of agreement between MOF probability estimated from TBS-adjusted MOF FRAX probability and FRAX probability using the “risk-equivalent” femoral BMD T-score: MOF probability r2 = 0.98, slope = 1.02, intercept = − 0.3; hip probability r2 = 0.95, slope = 1.07, intercept = 0.0.

Conclusions

The BMD-independent effect of lumbar spine TBS on fracture risk can be estimated as a simple offset to the BMD T-score.
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Literature
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go back to reference Roos NP, Shapiro E (1999) Revisiting the Manitoba Centre for Health Policy and Evaluation and its population-based health information system. Med Care 37(6 Suppl):JS10–JJS4PubMed Roos NP, Shapiro E (1999) Revisiting the Manitoba Centre for Health Policy and Evaluation and its population-based health information system. Med Care 37(6 Suppl):JS10–JJS4PubMed
Metadata
Title
Risk-equivalent T-score adjustment for using lumbar spine trabecular bone score (TBS): the Manitoba BMD registry
Authors
W. D. Leslie
E. Shevroja
H. Johansson
E. V. McCloskey
N. C. Harvey
J. A. Kanis
D. Hans
Publication date
01-03-2018
Publisher
Springer London
Published in
Osteoporosis International / Issue 3/2018
Print ISSN: 0937-941X
Electronic ISSN: 1433-2965
DOI
https://doi.org/10.1007/s00198-018-4405-0

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