Objective To explore the distribution of forearm bone mineral density (BMD) and to compare the BMD of the forearm with that in the lumbar spine and left hip detected by dual-energy X-ray absorptiometry (DXA),and to explore the diagnostic value of the forearm BMD in rheumatoid arthritis (RA) patients.Methods BMD of the lumber vertebrae,left hip,and non-dominant forearm in 200 postmenopausal female patients with RA was examined using DXA at the same time.BMD of different sites was compared.The diagnostic BMD cut-off value at the central axial and influential factors of peripheral BMD were explored.Results (1) The mean age of the 200 postmenopausal female patients was 55.9 ± 13.8 years.Based on their axial DXA data and fracture history,170 patients (85.0％) had abnormal BMD (T score ＜-1.0).(2) Compared with abnormal axial BMD group,forearm BMD in normal axial group significantly decreased [(0.33 ± 0.13) g/cm2 vs (0.44 ± 0.06) g/cm2,t =4.29,P ＜0.01].(3) Forearm BMD was significantly lower in patients whose disease duration was more than 1 year and positive of anti CCP antibody.(4) Forearm BMD was positively correlated with axial BMD.(5) The sensitivity and specificity for identifying osteoporosis in the lumber and left hip were 70.2％ and 77.4％,and 74.1％ and 70.6％,respectively,when the T-score threshold of forearm was defined as-2.65 and-2.5,respectively.(6) Multiple regression analysis showed that older age,long disease duration,and positive anti-CCP antibody were independent risk factors of abnormal forearm BMD in RA patients.Conclusion Forearm BMD is capable of screening osteoporosis defined by axial BMD in female RA patients.Patients with older age,longer disease duration,and positive anti-CCP antibody are vulnerable of BMD decrease.%目的 探讨绝经后女性类风湿关节炎患者前臂骨密度扫描的分布规律,并通过与椎体、髋部双能X线(DXA)进行对比,确定其在类风湿关节炎(RA)患者骨质疏松诊断中的价值.方法 采用DXA法,同时测量200例女性绝经后RA患者非优势侧前臂远端以及腰椎、左髋部骨密度.比较不同扫描部位之间骨密度值的关系,并探讨以诊断中轴骨密度异常的诊断界值,以及可能影响外周骨密度的因素.结果 (1)200例女性绝经RA患者平均年龄(55.9±13.8)岁.根据中轴DXA结果及骨折病史,170例(85.0％)骨密度异常(T值＜-1.0).(2)RA患者中轴骨密度异常组前臂远端骨密度(0.33 ±0.13) g/cm2,低于正常组(0.44±0.06) g/cm2,(t=4.29,P＜0.01).(3)病程1年以上、抗CCP抗体阳性RA患者前臂骨密度降低.(4)前臂骨密度与中轴骨密度呈正相关.(5)使用前臂骨密度诊断腰椎和左髋骨质疏松的最佳T值分别为-2.65(敏感度为0.702,特异度为0.774)和-2.50(敏感度为0.741,特异度为0.706).(6) Logistic回归分析显示,年龄(P =0.012)、病程(P =0.011)、以及抗CCP抗体阳性(P=0.05)分别是造成RA患者前臂BMD异常的独立危险因素.结论 RA患者前臂骨密度可以作为筛查女性类风湿关节炎患者中轴骨质疏松的辅助工具,高龄、疾病病程长以及抗CCP抗体阳性患者更容易出现骨密度下降.
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