Research Abstract

Morphometric Measurements: (Body Composition, Vertebral Fracture Recognition, Hip Geometry)

Body Composition Comparison Between Horizon A System and Lunar iDXA: The OsteoLaus Cohort

Thursday, March 30, 2023

1:10 PM – 1:20 PM

Location: Northbrook Ballroom

Primary Author(s)

Colin Vendrami, MD (he/him/his)

MD-PhD Student
Interdisciplinary Center of Bone Diseases, Rheumatology Unit, Bone and Joint Department, Lausanne University Hospital and University of Lausanne, Switzerland, Switzerland

Disclosure(s): No financial relationships to disclose

Contributing Author(s)

Enisa Shevroja, MD, PhD

Center of Bone Diseases, Rheumatology Unit, Bone and Joint Department, CHUV, Lausanne, Switzerland, Switzerland

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Guillaume Gatineau, MSc

Center of Bone Diseases, Rheumatology Unit, Bone and Joint Department, CHUV, Lausanne, Switzerland, Switzerland

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Elena Gonzalez Rodriguez, MD, PhD

Center of Bone Diseases, Rheumatology Unit, Bone and Joint Department, CHUV, Lausanne, Switzerland, Switzerland

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Lamy Olivier, Prof., MD, PhD

Head of the Service of Internal Medicine and of the Center of Bone Diseases
Center of Bone Diseases, Rheumatology Unit, Bone and Joint Department, CHUV, Lausanne, Switzerland and Internal Medicine Unit, Internal Medicine Department, CHUV, Lausanne, Switzerland, Switzerland

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Didier Hans, Prof., PhD, MBA

Head of Research and Development
Lausanne University Hospital, Switzerland

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Disclosure(s):

Colin Vendrami, MD, MSc: No financial relationships to disclose

Purpose/Aims: This study aims to compare body composition measures between two different devices of latest generation: Horizon A SystemTM (Hologic, Waltham, MA, USA) and Lunar iDXATM (GE Healthcare, Madison, Wi, USA).

Rationale/Background: Dual-energy X-Ray Absorptiometry (DXA) is one of the reference techniques for the assessment of body composition thanks to its reliability, low irradiation, and the capacity to measure regional and total fat, lean and bone parameters. As DXA measurements vary among different devices, it is crucial to assess their similarities and differences.

Methods: Post-menopausal women from the 5th visit of the OsteoLaus cohort underwent total body DXA assessment with both devices in the same day, within one hour. Two technicians: one for Horizon A and one for Lunar iDXA performed all the scans. We compared total fat mass (TFM) and percent fat (TPF), total lean mass (TLM), appendicular lean mass (ALM), total bone mineral content (BMC) and density (BMD) between the two DXAs with T-test for means, correlation (r) and with a complete Bland Altman analysis (regression, constant agreement, relative agreement).

Results: 805 participants were analyzed (age 72.9±6.8 years, BMI 25.5±4.5 kg/cm2). Compared to Lunar iDXA, Horizon A measures higher (p < 0.001) mean values for TFM +1418.1 g. (r=0.99), TPF +0.91% (r=0.99) and TLM +1090.3 g (r=0.96). Horizon A measures lower (p < 0.001) mean values for ALM -749.7 g. (r=0.97), BMC -216.3 g. (r=0.85) and BMD -0.050g/cm2 (r=0.81). The Bland Altman analysis shows different relative and constant agreement for each comparison between the devices (cf. figures).

Implications: A trend of higher soft tissues values were seen for Horizon A SystemTM, and of bone for Lunar iDXATM. These results suggest the presence of systematic differences, calibration differences and potential confounders between these two devices. These between-devices differences might be particularly impactfull on the use of these parameters’ cut-offs in clinical setting. Further in-depth analysis with cross-calibration equations is planned. This effort is beneficial for the diagnosis and clinical follow-up of diseases that rely on DXA-derived parameters.