目的: 探讨类风湿关节炎(rheumatoid arthritis，RA)患者合并低肌肉量综合征的特征及其对躯体功能的影响。方法: 纳入2019年9月至2024年4月就诊于中山大学孙逸仙纪念医院风湿免疫科的RA患者。收集所有患者的临床资料，包括病情活动、躯体功能及放射学评估，同时进行身体成分、握力和步行速度的测量，评估有无低肌肉量综合征以及营养不良、肌少症、肌少症性肥胖和恶病质，采用斯坦福健康评估问卷-残疾指数(health assessment questionnaire-disability index，HAQ-DI)评估躯体功能，并通过Logistic回归分析躯体功能障碍的影响因素。结果: 共纳入RA患者1 016例，女性占82.5%，平均年龄(52.4±12.5)岁。557例(54.8%)为低肌肉量综合征且均合并营养不良，在此基础上，326例(32.1%)合并肌少症，124例(12.2%)合并肌少症性肥胖，33例(3.2%)合并恶病质。共584例(57.4%)RA患者有躯体功能障碍，轻度、中度和重度躯体功能障碍分别有421例(41.4%)、124例(12.2%)和39例(3.8%)。与无低肌肉量综合征(n=459)或仅营养不良(n=231)的患者相比，同时合并营养不良+肌少症(n=326)的RA患者病情活动性高，躯体功能障碍比例较高(69.6% vs. 42.0% vs. 56.6%)，但仅营养不良的RA患者HAQ-DI评分(中位数0.0 vs. 0.1)和躯体功能障碍比例(42.0% vs. 56.6%)则较无低肌肉量综合征者低。多因素Logistic回归分析显示，营养不良+肌少症与躯体功能障碍呈独立正相关(OR=2.021，95%CI:1.067~3.828)，而仅营养不良则与躯体功能障碍无明显相关。结论: 同时合并营养不良和肌少症会加重RA患者病情活动性和躯体功能障碍，临床应重视RA患者低肌肉量综合征尤其是肌少症的筛查与评估，并予以及时干预。

Objective: To investigate the clinical characteristics of overlapping syndromes of low muscle mass in Chinese patients with rheumatoid arthritis (RA) and their impact on physical function. Methods: Consecutive patients with RA were recruited from September 2019 to April 2024 at Department of Rheumatology and Immunology, Sun Yat-Sen Memorial Hospital. Clinical data including disease acti-vity, physical function and radiographic assessment were collected. All patients also finished measurement of body composition, grip strength, and gait speed, and overlapping syndromes of low muscle mass as well as malnutrition, sarcopenia, sarcopenic obesity, and cachexia were evaluated. The Stanford health assessment questionnaire- disability index (HAQ-DI) was used to evaluate physical function. Logistic regression was used to analyze the related factors of physical dysfunction. Results: A total of 1 016 RA patients were recruited. Their mean age was (52.4±12.5) years, and 82.5% were female. There were 557 cases (54.8%) with overlapping syndromes of low muscle mass and all of them were malnutrition. On this basis, 326 cases (32.1%) exhibited sarcopenia, 124 (12.2%) sarcopenic obesity, and 33 (3.2%) cachexia. There were 584 (57.4%) of RA patients having physical dysfunction, with varying degrees of severity 421 (41.4%) mild, 124 (12.2%) moderate, and 39 (3.8%) severe. Compared with patients without overlapping syndromes of low muscle mass (n=459) or with malnutrition only (n=231), RA patients with both malnutrition and sarcopenia (n=326) had significantly higher core disease activity indicators and higher rate of physical dysfunction (69.6% vs. 42.0% vs. 56.6%). However, compared with patients without overlapping syndromes of low muscle mass, patients with malnutrition only had lower HAQ-DI score (median 0.0 vs. 0.1) and lower rate of physical dysfunction (42.0% vs. 56.6%). Multivariate Logistic regression analysis showed that simultaneously overlapping malnutrition and sarcopenia were associated factors of physical dysfunction (OR=2.021, 95%CI: 1.067-3.828), but malnutrition only was not. Conclusion: Simultaneously overlapping malnutrition and sarcopenia can deteriorate disease activity and physical dysfunction in RA patients. The screening and evaluation of overlapping syndromes of low muscle mass, especially sarcopenia should be emphasized in patients with RA.