Background/Purpose: Sarcopenia, i.e., loss of skeletal muscle mass and strength, has been associated with multiple adverse health outcomes, including mortality. We have previously demonstrated associations of the SARC-F, a simple self-report screening tool for sarcopenia, with functional outcomes in adults with systemic lupus erythematosus (SLE). However, to our knowledge, whether the SARC-F is associated with objective measures of sarcopenia in patients with SLE has not been explored [1]. Accordingly, this study sought to assess the association of the SARC-F with dual energy x-ray absorptiometry (DXA)-based definitions of sarcopenia.

Methods: Women 18-70 years of age with validated SLE were enrolled in a single-center cross-sectional study. Sociodemographic characteristics, clinical features, and the SARC-F (which includes questions on strength, assistance walking, rising from a chair, climbing stairs, and falls) were self-reported or collected from the patient’s electronic medical record. Disease activity and damage were provided by treating physicians. Sarcopenia was measured via DXA using 4 consensus definitions. Descriptive statistics were used to compare sociodemographic characteristics, clinical features, SLE disease severity, and objective measures of sarcopenia between participant groups. SARC-F scores were dichotomized as ≥4 (i.e., at risk for sarcopenia) versus < 4 (i.e., not at risk for sarcopenia) based on established cut points. Fisher’s exact tests evaluated the relationship between the SARC-F and objective measures of sarcopenia.

Results: Of 57 participants, 16 (29%) were at risk for sarcopenia based on SARC-F score ≥4 (Table 1). Participants with SARC-F ≥4 were older (p=0.02) and had greater organ damage (p< 0.01) and slower gait speed (p< 0.01 to p=0.04) than those with SARC-F < 4 (Tables 1 and 2). Among 56 women who had DXA, there were no significant associations between the SARC-F and any of the 4 standard validated measures of objective sarcopenia (Table 3). The European Working Group on Sarcopenia in Older People definition had the highest specificity (data not shown).

Conclusion: In this exploratory study of adult women with SLE, very few participants had low muscle mass meeting DXA-based definitions of sarcopenia. In non-elderly women with SLE, DXA scores with a lower threshold for sarcopenia, without BMI adjustment (i.e., European Working Group on Sarcopenia in Older People definition), may preferentially identify those at risk for sarcopenia. Ongoing studies in larger cohorts are needed.References:1. Malmstrom et al. J Cachexia Sarcopenia Muscle 2016;7:28-36.

Table 1. Sociodemographic and disease characteristics and SARC-F components of adults with systemic lupus erythematosus (SLE) with high (≥4) versus low ( < 4) SARC-F scores

Table 2. Objective sarcopenia measures of adults with systemic lupus erythematosus with high (≥4) versus low ( < 4) SARC-F scores

Table 3. Cross sectional association of SARC-F with objective sarcopenia definitions

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparison-of-the-sarc-f-with-objective-measures-of-sarcopenia-in-women-with-systemic-lupus-erythematosus/