Purpose: This study aimed to determine the validity of ultrasonographic measurement of the rectus femoris muscle (RFM) thickness as a screening tool for low appendicular muscle mass (ASM) to diagnose sarcopenia and to determine the cut-off point of RFM thickness in the Thai population.
Patients and methods: We enrolled 857 community-dwelling adults aged 60 years and older who were diagnosed with sarcopenia using the Asian Working Group for Sarcopenia-2019 algorithm. The RFM thickness was measured using ultrasonography and compared with bioelectrical impedance analysis (BIA) data. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were evaluated, and the area under the receiver operating curve (AUROC) was used to determine the accuracy of the test.
Results: A total of 857 participants were included in the study. Overall, when the cut-off values of RFM thickness of ≤ 1.1 cm were used for male and ≤ 1 cm for female, the highest sensitivity for sarcopenia diagnosis was 90.9% and specificity was 92.2%. The PPV was 76.6, and the NPV was the highest at 97.3. The highest sensitivity for the diagnosis of severe sarcopenia was 92.5% and specificity was 97.4%. The AUROC of the cut-off point of RFM thickness for the diagnosis of sarcopenia was 0.92 (95% confidence interval [CI], 0.89− 0.94); for severe sarcopenia, it was 0.95 (95% CI, 0.92− 0.98).
Conclusion: Measuring RFM thickness using ultrasonography is a feasible and reliable screening test for sarcopenia, and the cut-off values of ≤ 1.1 cm for male and ≤ 1 cm for female showed the highest accuracy for confirming low ASM in the Thai population.

Keywords: sarcopenia, rectus femoris muscle, ultrasonography, bioelectrical impedance


中文翻译：

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泰国人群肌肉减少症老年人股直肌超声测量的有效性

目的：本研究旨在确定超声测量股直肌 (RFM) 厚度作为低附肢肌肉质量 (ASM) 筛查工具以诊断肌肉减少症并确定泰国 RFM 厚度截止点的有效性。人口。
患者和方法：我们使用亚洲肌肉减少症工作组 2019 算法招募了 857 名 60 岁及以上被诊断患有肌肉减少症的社区居民。RFM 厚度使用超声测量并与生物电阻抗分析 (BIA) 数据进行比较。评估敏感性、特异性、阳性预测值（PPV）和阴性预测值（NPV），并使用受试者工作曲线下面积（AUROC）来确定测试的准确性。
结果：共有 857 名参与者被纳入研究。总体而言，当 RFM 厚度 ≤ 1.1 cm 用于男性和 ≤ 1 cm 用于女性时，诊断肌肉减少症的最高敏感性为 90.9%，特异性为 92.2%。PPV 为 76.6，NPV 最高，为 97.3。诊断严重肌肉减少症的最高敏感性为 92.5%，特异性为 97.4%。用于诊断肌肉减少症的 RFM 厚度分界点的 AUROC 为 0.92（95% 置信区间 [CI]，0.89-0.94）；对于严重的肌肉减少症，它是 0.95（95% CI，0.92-0.98）。
结论：使用超声测量 RFM 厚度是一种可行且可靠的肌肉减少症筛查测试，男性 ≤ 1.1 cm 和女性 ≤ 1 cm 的临界值显示在泰国人群中确认低 ASM 的准确度最高。

关键词：肌肉减少症，股直肌，超声检查，生物电阻抗