Wolfe Frederick, Michaud Kaleb, Pincus Theodore, Furst Daniel, Keystone Edward
National Data Bank for Rheumatic Diseases, Wichita, Kansas 67214, USA.
Arthritis Rheum. 2005 Dec;52(12):3873-9. doi: 10.1002/art.21494.
The Disease Activity Score (DAS) is widely used in clinical trials. A DAS of 5.1 defines the level of severe rheumatoid arthritis (RA) and is the criterion for the initiation of anti-tumor necrosis factor therapy in the UK and The Netherlands. In North America, similar rules are sometimes imposed. However, it is not known how accurately the DAS characterizes RA activity. The present study was undertaken to determine the concordance between DAS scores and physicians' assessments of RA activity, to investigate factors relating to discrepancies, and to assess the suitability of using the DAS in individual patients.
Six hundred sixty-nine RA patients were assessed using the DAS and other clinical measures. A physician's global estimate of RA activity was performed using an 11-point predefined scale and a standard definition of disease activity.
The DAS and physician global assessment had substantially different distributions of values. The level of agreement (Kendall's tau-a) between DAS scores and physician global assessments was 49% (95% confidence interval 45-53%), Lin's coefficient of concordance was 0.62, and the Bland-Altman 95% limits of agreement were -3.17 and 3.99. These results suggest poor-to-moderate concordance between the 2 measures of disease activity.
The DAS and the physician's assessment of RA activity do not approach, value, and weight RA variables to the same extent, suggesting that RA activity is not evaluated similarly by North American physicians and with the DAS. The scales do not have acceptable levels of concordance. There is too much inherent variability in the DAS and other RA scales (e.g., the Health Assessment Questionnaire) to recommend them as sole determinants of RA activity for clinical or regulatory purposes.
疾病活动评分（DAS）在临床试验中被广泛应用。DAS为5.1定义了严重类风湿关节炎（RA）的水平，并且是英国和荷兰启动抗肿瘤坏死因子治疗的标准。在北美，有时也会采用类似的标准。然而，尚不清楚DAS对RA活动的表征有多准确。本研究旨在确定DAS评分与医生对RA活动评估之间的一致性，调查与差异相关的因素，并评估在个体患者中使用DAS的适用性。
使用DAS和其他临床指标对669例RA患者进行评估。医生使用11分预定义量表和疾病活动的标准定义对RA活动进行整体评估。
DAS和医生整体评估的数值分布有很大差异。DAS评分与医生整体评估之间的一致性水平（肯德尔tau-a）为49%（95%置信区间45 - 53%），林氏一致性系数为0.62，布兰德-奥特曼95%一致性界限为-3.17和3.99。这些结果表明两种疾病活动测量方法之间的一致性较差至中等。
DAS和医生对RA活动的评估在对RA变量的接近程度、赋值和权重方面不尽相同，这表明北美医生和DAS对RA活动的评估方式不同。这些量表的一致性水平不可接受。DAS和其他RA量表（如健康评估问卷）存在太多内在变异性，无法推荐将它们作为临床或监管目的下RA活动的唯一决定因素。
