目的：了解计算骨折危险性评估工具（fracture risk assessment tool，FRAX）时，使用与不使用骨密度（bone mineral density，BMD）对中国类风湿关节炎（rheumatoid arthritis，RA）患者骨折概率的影响，分析影响骨量的因素。方法：2009年12月至2012年12月于北京大学第一医院门诊及病房首次就诊的年龄大于40岁RA患者200例，双能X线测定腰椎和左髋部BMD，将使用与不使用BMD或T值计算的FRAX骨折概率进行比较，并结合患者的性别、年龄、绝经时间、体重指数、病程以及激素应用等因素进行相关性分析。结果：200例患者平均年龄（59.4±10.2）岁，77.5%为女性。有77例患者接受了双能X线检查，其中BMD正常和异常组分别为10例（13%）和67例（87%），有32例患者发生骨折。两组患者在平均年龄、糖皮质激素使用（用药时间、累积剂量、目前日平均剂量）、FRAX预测主要部位和髋部骨折风险之间差异均有统计学意义。使用与不使用BMD、T值计算的未来10年骨折概率差异无统计学差异。结合T值得出的FRAX预测骨折风险的ROC曲线下面积最大（0.899）。以腰椎及髋部的BMD作为结果变量，对影响患者BMD的因素进行多元回归分析显示：患者的疼痛评分（P=0.02）、既往发生骨折（P=0.003）、糖皮质激素的累积剂量（P=0.008）是引起腰椎骨量异常的危险因素，患者的年龄（P<0.001）、已绝经（P=0.05）、既往发生骨折（P=0.003）、体重指数（P=0.03）是引起左髋部骨量异常的危险因素。结论：RA患者骨折发生比例较高，主要部位和髋部骨折风险均增加，结合股骨颈BMD或T值计算FRAX能更有效地预测骨折概率。

Objective：To verify the fracture risk assessment tool (FRAX) to estimate the probability of osteoporotic fracture in patients with rheumatoid arthritis (RA) with or without bone mineral density (BMD), and identify associated risk factors of osteoporosis. Methods: In the study, 200 patients with rheumatoid arthritis aged more than 40 years in Peking University First Hospital from Dec. 2009 to Dec. 2012 were recruited. Clinical information was obtained from a questionnaire of their case history and medical records. FRAX tool was administered. Their lumber spine and left femoral BMD were determined by dual energy X ray absorptiometry. The gender, age, disease duration, menopause status, body mass index (BMI) and accumulative dose of glucocorticoid were obtained in retrospect. Correlation analysis was conducted between the BMD and clinical information. Results:The study population (female, 77.5%) had a mean age of 59.4 years, in which 10 (13%) patients showed a normal BMD, 67 (87%) were osteopenia or osteoporosis, while 32 patients (16%) had fragile fracture. Compared with the patients with normal BMD, the subjects with low BMD had significantly older age, longer period for corticoids usage, higher day dose and accumulated dose of corticoids.The 10-year fracture risk of sustai-ning major osteoporotic fractures and hip fracture was higher. No significant difference was observed between the 10-year fracture risks calculated with BMD and without BMD. The values of the different area under the receiver operating characteristic (ROC) curve (AUC) for major and hip fractures calculated in three ways: without BMD, with the femoral neck BMD, and with T-score. The best result was for FRAX tool for hip fracture with the T-score (AUC 0.899). A stepwise multivariate linear regression model was constructed to explore the relationship between the different clinical factors studied and a low BMD. Three statistically significant variables for lumber BMD were pain on visual assessment scale (VAS) (P=0.02), fracture history (P=0.003) and a higher steroid accumulated dose (P=0.008). Three statistically significant variables for left hip BMD were age (P<0.001), fracture history (P=0.05) and lower BMI (P=0.03). Conclusion: Low BMD is a common complication in RA patients. Risk factors for major fracture and hip fracture are increased. There is a positive correlation between FRAX calculated with and without BMD or T score. FRAX with the femoral neck T score or BMD presents a discriminatory capacity better than FRAX without BMD, according to the AUC ROC.