Date: Sunday, October 21, 2018
Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Axial spondyloarthropathy (axSpA) patients have an increased risk of developing osteoporosis compared to matched controls. Dual energy x-ray absorptiometry (DXA) is the technique of choice to detect low bone mineral density (BMD). Quantitative ultrasound (QUS) of the calcaneus measures 3 parameters of bone: speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness index (SI; composite of SOS and BUA) and can predict fragility fractures in postmenopausal women. QUS is cheap, portable and does not use any ionising radiation. It also provides information on bone microarchitecture, as well as bone mineral density (BMD). Few studies have investigated the use of QUS in axSpA. We aimed to investigate relationships between DXA and QUS in a well characterised axSpA cohort.
Patients fulfilling modified New York (mNY) or Assessment of Spondyloarthritis International Society (ASAS) criteria were consecutively recruited from rheumatology clinics in this twin-centre cross-sectional study. DXA assessed BMD at the spine, hip and radius. QUS of the calcaneus generated SOS, BUA and SI. Patients had a detailed assessment that included demographics, clinical exam, laboratory assessment and validated measures of disease severity (BASDAI, ASDAS-CRP, BASMI, mSASSS) collected. SPSS was used for statistical analysis.
A total of 107 patients were included: 76% male, 81% mNY criteria, median (IQR) age 51.5 (17.8) years, disease duration 23.5 (20.4) years, BASDAI 3.9 (3.6), ASDAS-CRP 2.1 (1.5) and BASMI 4.1 (3.2). Fragility fracture prevalence was low (6%).
Using DXA, 16.3% had osteoporosis, 41.3% of the cohort had osteopenia and 42.3% had normal BMD as per WHO criteria. Using QUS, 2.9% of the cohort had osteoporosis, 33.7% had osteopenia and 63.5% had normal BMD. Sensitivity of the QUS was 72% in detecting low BMD, specificity was 51%, positive predictive value was 71% and negative predictive value was 53%.
There was no difference in QUS parameters in the fractured versus non-fractured group; however fragility fractures occurred uncommonly in this cohort.
Each QUS parameter (BUA, SOS, SI) was compared with DXA measurements: BUA correlated significantly (p<0.05) with all DXA sites (spine r=0.39, femoral neck r=0.33, total hip r=0.37, radius r=0.34), as did SI (spine r=0.32, femoral neck r=0.36, total hip r=0.35, total forearm r=0.37). There was no correlation between SOS and DXA measurements.
In univariate regression analysis, age, gender, BMI, and QUS parameters BUA and SI were independently associated with BMD by DXA. In multivariate regression models, when controlling for age, gender and BMI, both BUA and SI remained independent predictors of BMD at all DXA sites.
Quantitative ultrasound of the heel is independently associated with DXA measurements of BMD in this axSpA cohort. To become clinically useful, more research is needed to determine the subgroup of patients it performs most accurately in, as well as its association with fracture risk. However, QUS of the calcaneus is a promising tool which may be incorporated in assessment for low BMD in axSpA.
To cite this abstract in AMA style:Fitzgerald G, Anachebe T, Mullan R, Kane D, McCarroll K, O' Shea F. Quantitative Ultrasound of the Calcaneus Has a Role to Play in Detecting Low Bone Mineral Density in Axial Spondyloarthropathy Patients [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 10). https://acrabstracts.org/abstract/quantitative-ultrasound-of-the-calcaneus-has-a-role-to-play-in-detecting-low-bone-mineral-density-in-axial-spondyloarthropathy-patients/. Accessed January 24, 2021.
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