目的: 分析超重和肥胖类风湿关节炎(rheumatoid arthritis，RA)患者的临床特点，并分析体重指数(body mass index，BMI)与疾病特征的相关性。方法: 回顾性收集2015年1月至2020年12月于北京大学第三医院风湿免疫科住院的RA患者的病例资料，包括人口学特征、疾病活动度、关节外表现、合并症、实验室指标和治疗用药等。根据WHO定义，BMI≥30 kg/m²为肥胖组，25≤BMI < 30 kg/m²为超重组，18.5≤BMI < 25 kg/m²为体质量正常组，BMI < 18.5 kg/m²为体质量减低组。分析超重和肥胖RA患者的临床特征。统计学方法符合正态分布的定量资料采用 t检验，非正态分布的定量资料采用Wilcoxon秩和检验。定性资料采用χ²检验，1≤理论频数 < 5采用校正四格表χ²检验，理论频数 < 1采用确切概率法。采用Logistic回归校正混杂因素分析超重和肥胖是否与合并症有关。结果: 共纳入481例RA患者，平均BMI值为(23.28±3.75) kg/m²。BMI < 18.5 kg/m² 31例(6.5%)，18.5≤BMI < 25 kg/m² 309例(64.2%)，合计340例(70.7%)。超重者(25≤BMI < 30 kg/m²)119例(24.7%)，肥胖者(BMI≥30 kg/m²)22例(4.6%)，两者合计141例(29.3%)。超重和肥胖RA患者罹患高血压(57.4% vs. 39.1%，P < 0.001)、糖尿病(25.5% vs. 15.0%，P=0.006)、高脂血症(22.7% vs. 10.9%，P=0.001)、脂肪肝(28.4% vs. 7.4%，P < 0.001)、骨关节炎(39.0% vs. 29.4%，P=0.040)的比例较体质量正常和减低者明显增高，合并骨质疏松(59.6% vs. 70.9%，P=0.016)、贫血(36.2% vs. 55.6%，P < 0.001)的比例较体质量正常和减低者明显降低，但两者在合并冠状动脉性心脏病(5.7 % vs. 7.6%，P=0.442)、脑血管疾病(6.4% vs. 8.8%，P=0.372)以及外周动脉粥样硬化(9.2% vs. 7.6%，P=0.565)方面差异则无统计学意义。超重和肥胖RA患者的中位C反应蛋白(C- reactive protein，CRP，1.52 mg/dL vs. 2.35 mg/dL，P=0.008)、中位红细胞沉降率(erythrocyte sedimentation rate，ESR，34.0 mm/h vs. 50.0 mm/h，P=0.003)、疼痛视觉模拟评分(visual analogue scale，VAS，3.66±3.08 vs. 4.40±2.85, P=0.011)以及28个关节疾病活动度评分(disease activity score 28，DAS28，5.05±1.60 vs. 5.45±1.52，P=0.010)均低于体质量正常和减低组。多因素回归分析发现超重和肥胖是高血压、糖尿病、高脂血症、脂肪肝的独立危险因素，同时对骨质疏松和贫血具有保护性作用。结论: RA患者中超重和肥胖者疾病活动度更低，超重和肥胖与高血压、糖尿病、高脂血症具有相关性，但与心脑血管疾病不具有相关性。

Objective: To analyze the clinical features of overweight and obese rheumatoid arthritis (RA)patients, and the relationship between body mass index (BMI) and disease characteristics. Methods: The demographic data, extra-articular manifestations, comorbidities, and disease activity of RA patients admitted to the Rheumatology and Immunology Department of Peking University Third Hospital from January 2015 to December 2020 were collected, and the above characteristics of overweight and obese RA patients were retrospectively analyzed. According to the WHO, BMI≥30 kg/m² referred to obese individuals, 25≤BMI < 30 kg/m² referred to overweight individuals, 18.5≤BMI < 25 kg/m² referred to normal individuals, BMI < 18.5 kg/m² referred to reduced body mass individuals. t test was used for the quantitative data in accordance with normal distribution. Wilcoxon rank sum test was used for the quantitative data of non-normal distribution. The qualitative data were analyzed by chi square test. But while 1≤theoretical frequency < 5, Chi square test of corrected four grid table was used. And Fisher exact probability method was used when theoretical frequency < 1. Analyzing whether overweight or obesity was associated with comorbidities using Logistic regression adjusted confounding factors. Results: A total of 481 RA patients were included in this study, with an average BMI value of (23.28±3.75) kg/m².Of the patients, 31 cases (6.5%) were with BMI < 18.5 kg/m², 309 cases (64.2%) with 18.5≤ BMI < 25 kg/m², amounting to 340 cases (70.7%). There were 119 overweight individuals (25≤ BMI < 30 kg/m², 24.7%) and 22 obese individuals (BMI≥30 kg/m², 4.6%), totaling 141 (29.3%).The proportion of the overweight and obese RA patients suffering from hypertension (57.4% vs. 39.1%, P < 0.001), diabetes (25.5% vs. 15.0%, P=0.006), hyperlipidemia (22.7% vs. 10.9%, P=0.001), fatty liver (28.4% vs. 7.4%, P < 0.001), osteoarthritis (39.0% vs. 29.4%, P=0.040) was significantly higher, and the proportion of the patients with osteoporosis(59.6% vs. 70.9%, P=0.016) and anemia (36.2% vs. 55.6%, P < 0.001) was significantly lower. However, there was no difference between the two groups in coronary heart disease (5.7% vs. 7.6%, P=0.442), cerebrovascular disease (6.4% vs. 8.8%, P=0.372) and peripheral atherosclerosis (9.2% vs. 7.6%, P=0.565).The median C-reactive protein (CRP, 1.52 mg/dL vs. 2.35 mg/dL, P=0.008), median erythrocyte sedimentation rate (ESR, 34.0 mm/h vs. 50.0 mm/h, P=0.003), pain visual simulation score (VAS) (3.66±3.08 vs. 4.40±2.85, P=0.011), and 28 joint disease activity scores (DAS-28, 5.05±1.60 vs. 5.45±1.52, P=0.010) in the overweight and obese RA group were all lower than those in the normal and reduced weight groups. Multivariate regression analysis showed that overweight and obesity was an independent risk factor for hypertension, diabetes, hyperlipidemia and fatty liver, and had protective effects on osteoporosis and anemia. Conclusion: In RA patients, RA disease activity is lower in overweight and obesity patients. Overweight and obesity is associated with hypertension, diabetes and hyperlipidemia, but not with cardiovascular and cerebrovascular diseases.