目的: 分析类风湿关节炎(rheumatoid arthritis，RA)合并下肢静脉血栓患者的临床特点，提高对该病的认识。方法: 选择自2013年11月1日至2020年12月31日期间在北京大学第三医院风湿免疫科住院的RA患者502例，回顾性分析入院诊断无下肢静脉血栓，出院诊断包含下肢静脉血栓的RA患者的临床和实验室检查指标特点，并将该组患者定义为血栓组，其他不合并下肢静脉血栓的患者作为对照组，进行两组间单因素分析，并对差异有统计学意义的因素进行多因素Logistic回归分析。结果: 血栓组患者34例(6.77%)，对照组468例(93.23%)。血栓组年龄34~86岁(中位年龄71岁)，女性23例，男性11例；单侧下肢静脉血栓20例(58.8%)，双侧下肢静脉血栓14例(41.2%)，其中3例(8.8%)合并肺栓塞(低危)。血栓组中17例(50.0%)患者入院前卧床大于1周或需要借助拐杖/轮椅活动，29例(85.3%)患者存在下肢大关节受累，髋关节、膝关节、踝关节以及膝、髋关节同时受累的患者分别为1、22、2和4例。血栓组28个关节疾病活动度评分(disease activity scores 28，DAS28)处于高、中、低疾病活动的患者分别为23例(67.6%)、9例(26.5%)和2例(5.9%)。有21例血栓组患者完善了易栓症相关检查，1例抗心磷脂抗体阳性，2例狼疮抗凝物阳性，1例抗β2-糖蛋白1抗体阳性，其余均为阴性。血栓组患者年龄[71(60, 77)岁vs. 60 (51, 68)岁，Z =-3.873, P＜0. 01)]和血小板(platelet, PLT)水平[(328.53×10⁹±119.06×10⁹) /L vs.(278.68×10⁹±104.50×10⁹)/L, t =2.660, P＜0.01] 均显著高于对照组，血栓组D-二聚体升高(94.1% vs.66.4%, χ²=11.192，P＜0.01)以及类风湿因子(rheumatoid factor, RF)阳性(85.3% vs.67.1%，χ² =4.852，P＜0.05)的比例均显著高于对照组。Logistic回归分析发现RA发生下肢静脉血栓的危险因素包括年龄(OR =1.063, 95%CI: 1.026 ~ 1.101, P =0.001)、D-二聚体升高(OR =4.968, 95%CI: 1.136 ~ 21.730，P =0.033)和PLT水平(OR =1.004, 95%CI: 1.001 ~ 1.007, P =0.022)。结论: RA患者具有潜在下肢静脉血栓的风险，对于年龄大、D-二聚体和PLT升高，尤其是长时间卧床制动、高疾病活动度的RF阳性患者，需高度警惕下肢静脉血栓的风险。

Objective: To analyze the clinical characteristics of patients with rheumatoid arthritis (RA) complicated with venous thrombosis of lower extremities, and to improve the awareness of this condition. Methods: The clinical and laboratory data of 502 RA patients hospitalized in Department of Rheumatology and Immunology Peking University Third Hospital from November 1, 2013 to December 31, 2020 were collected, retrospective analysis was made on the RA patients who were diagnosed with lower limb vein thrombosis on discharge but hadn't on admission, the patients in this group were defined as thrombosis group, and the other patients without lower limb vein thrombosis were taken as control group. Single factor analysis was conducted between the two groups. Then multivariate Logistic regression analysis was used to analyze the independent risk factors of RA complicated with lower limb venous thrombosis with statistical significance in univariate analysis. Results: There were 34 patients (6.77%) in the thrombosis group and 468 patients (93.23%) in the control group. The age of thrombosis group was 34-86 years (median age was 71 years); 23 were female and 11 were male; there were 20 cases with unilateral lower limb vein thrombosis and 14 cases with bilateral lower limb vein thrombosis; pulmonary embolism in 3 cases (low risk).In the thrombosis group 17 (50.0%) patients were bedridden for more than one week or needed crutches/wheelchairs before admission. 29 cases(85.3%)had large joint involvement of lower extremities, including 22 cases of knee joint involvement, 1 case of hip joint involvement, 2 cases of ankle joint involvement, and 4 cases with both knee and hip joint involvement. In the thrombosis group, the high, middle and low disease activity scores 28(DAS28) were 23 (67.6%), 9 (26.5%) and 2 (5.9%), respectively. There were 21 patients in the thrombosis group had completed thrombosis related examinations, only 4 patients were positive for anti-cardiolipin antibody or anti-β2 glycoprotein 1 antibody or lupus anticoagulant, the rests were all negative. In the thrombosis group, age and platelet (PLT) level were significantly higher than those in the control group [71 (60, 77) years vs. 60 (51, 68) years, Z=-3.873, P < 0.01, (328.53× 10⁹±119.06 × 10⁹) /L vs.(278.68 × 10⁹±104.50 × 10⁹)/L, t=2.660, P < 0.01, respectively]. The proportion of D-Dimer increased in the thrombosis group as well as the positivity rheumatoid factor (RF) was much higher than those in the control group (94.1% vs.66.4%, χ²=11.192, P < 0.01; 85.3% vs.67.1%, χ²=4.852, P < 0.05, respectively). Multivariate Logistic regression analysis showed that age (OR=1.063, 95%CI: 1.026-1.101, P=0.001), D-Dimer increased (OR=4.968, 95%CI: 1.136-21.730, P=0.033) and PLT level (OR=1.004, 95%CI: 1.001-1.007, P=0.022) were the independent risk factors for RA complica-ted with lower extremity venous thrombosis. Conclusion: RA patients have potential risk of thrombosis of lower extremities. For the older age, D-Dimer and PLT elevated, especially those who were bedridden, RF positive and had high disease activity, should be alert to the risk.