The Diagnostic Accuracy of Ultrasound for Low Muscle Mass in Women with Systemic Sclerosis

Lucas Dória¹, Vanessa Hax², André Mallmann², Rafaela Santo³, Leonardo Santos², Stephanie Pilotti², Daniel Moraes², Isabella Boening², Pedro Glanze², ODIRLEI MONTICIELO¹, Ricardo Xavier⁴ and Rafael Chakr⁵, ¹Hospital de Clinicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil, ²Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil, ³Health Research and Innovation Science Centre, Klaipeda University, Klaipeda, Lithuania, Porto Alegre, Rio Grande do Sul, Brazil, ⁴Universidade Federal do Rio Grande do Sul, Porto Alegre/RS, Rio Grande do Sul, Brazil, ⁵Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil

Meeting: ACR Convergence 2024

Keywords: Dual energy x-ray absorptiometry (DEXA), Muscle Function, Musculoskeletal Examination, Scleroderma, Systemic, Ultrasound

Session Information

Date: Saturday, November 16, 2024

Title: Systemic Sclerosis & Related Disorders – Clinical Poster I

Session Type: Poster Session A

Session Time: 10:30AM-12:30PM

Background/Purpose: Patients with systemic sclerosis (SSc) often experience body composition changes, including low muscle mass (myopenia), associated with physical disability, hospitalization and death. Our purpose was to estimate the best cut-off value for low muscle mass diagnosis in SSc patients using ultrasound (US) for muscle thickness measurement.

Methods: This study has been approved in accordance with the Declaration of Helsinki principles and all subjects provided written informed consent. Women meeting the ACR/EULAR 2013 SSc criteria were consecutively enrolled between 2022 and 2023. Electronic medical records provided data on age, disease duration, cutaneous subtype, modified Rodnan’s skin score (mRSS), and the EUSTAR activity index.

Appendicular skeletal muscle mass (ASM, kg) was quantified by dual-energy X-ray absorptiometry (DXA). Low muscle mass was defined as ASM < 15 kg. Muscle thickness of vastus lateralis (VL, cm) was assessed real-time. Two independent investigators measured the VL images, and the mean of their measurements was considered for analysis . Pearson correlation coefficient, diagnostic accuracy (sensitivity, specificity, ROC curve, and AUC), and Kappa concordance were analyzed (p< 0.05).

Results: Eighty patients were included [mean age of 60.7±11.2 years old and a median disease duration of 11.0 (5.0–18.5) years]. Twenty percent of the participants had diffuse cutaneous SSc. The median mRSS was 4.0 (2.0–7.8), and the median EUSTAR index was 1.7 (1.1–3.1). The mean ASM was 16.0 ± 2.3 kg and 25% of patients showed low ASM. The mean thickness of VL was 1.8±0.4 cm. Low ASM was associated with low muscle thickness of VL (r=0.601, p< 0.001). The AUC for VL versus ASM was 0.849 (95% CI: 0.764-0.935, p< 0.001, Figure 1). The estimated VL cut-off was 1.26 cm, with 90.0% sensitivity and 75.0% specificity compared to ASM (Kappa=0.534, p< 0.001).

Conclusion: In our study, VL thickness measured by US was associated with low ASM by DXA and a cut-off of 1.26 cm was sensitive enough to encourage future research on the use of US as a screening and monitoring tool for myopenia in SSc women.

Figure 1. ROC curve of vastus lateralis thickness in comparison to low appendicular skeletal muscle mass by DXA

Disclosures: L. Dória: None; V. Hax: None; A. Mallmann: None; R. Santo: None; L. Santos: None; S. Pilotti: None; D. Moraes: None; I. Boening: None; P. Glanze: None; O. MONTICIELO: AbbVie/Abbott, 6, AstraZeneca, 6, GlaxoSmithKlein(GSK), 6, Janssen, 6, UCB, 6; R. Xavier: None; R. Chakr: None.

To cite this abstract in AMA style:

Dória L, Hax V, Mallmann A, Santo R, Santos L, Pilotti S, Moraes D, Boening I, Glanze P, MONTICIELO O, Xavier R, Chakr R. The Diagnostic Accuracy of Ultrasound for Low Muscle Mass in Women with Systemic Sclerosis [abstract]. Arthritis Rheumatol. 2024; 76 (suppl 9). https://acrabstracts.org/abstract/the-diagnostic-accuracy-of-ultrasound-for-low-muscle-mass-in-women-with-systemic-sclerosis/. Accessed .

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