比較抗環瓜氨酸多肽抗體（Anti-CCP）及類風濕性因子（RF）在頑固型及緩解型類風濕性關節炎的診斷價值

The diagnostic value of anti-CCP and rheumatoid factor for patients with refractory rheumatoid arthritis (RA) and RA in remission

目的：比較anti-CCP及RF在頑固型及緩解型類風濕性關節炎的診斷價值。方法：我們總共收納了一百四十三位女性參與者並且將她們分成三組：五十一位經MTX治療後效果不良者為第一組（頑固型類風濕性關節炎病患）；四十三位經MTX治療後達完全緩解者為第二組（緩解型類風濕性關節炎病患）；四十九位健康對照者為第三組。我們測量所有參與者的anti-CCP及RF值並且測定這兩種方法的敏感度及特異度。以接受者操作特徵曲線（receiver operating characteristic）來比較anti-CCP及RF在不同臨界值（cut off points）對此二組病患所展現的敏感度及特異度。我們也計算及比較這兩種檢測方法的偽陰性比率與所呈現出來的互補診斷作用的優劣。結果：Anti-CCP及RF在第一組的敏感度分別為84%及78%，在第二組的敏感度分別為74%及67%。由接受者操作特徵曲線的分析東看，不論在第一組或第二組anti-CCP所展現出的敏感度及特異度都比RF來的高。當RF呈現陰性結果時，anti-CCP可提供較佳的互補診斷作用。結論：不論在診斷頑固型及緩解型的類風濕性關節炎，anti-CCP都比RF有較佳的敏感度及特異度。

Objective. To compare the diagnostic value of antibodies to cyclic citrullinated peptides (anti-CCP) and rheumatoid factor (RF) for patients with refractory rheumatoid arthritis (RA) and RA in remission. Methods. A total of one hundred and forty three participants were enrolled: fifty one patients with RA refractory to standard methotrexate therapy, group 1 (Gr I, refractory RA); forty three RA patients in complete remission status for at least 3 months, group II (Gr II, RA in remission); and forty nine community-based healthy controls, group III (Gr III). Levels of anti-CCP and RF were measured for all of the subjects. The sensitivity and specificity of both tests were determined via these subjects. The receiver operating characteristic (ROC) analysis was used to display the pairs of sensitivity and specificity for different cut off points of anti-CCP and RF. False negative rate and the complementary diagnostic effect of both assays were also calculated and compared. Results. The sensitivity of anti-CCP and RF for Gr I were 84% and 78%, and 74% and 67% for Gr II, respectively. The specificity of anti-CCP and RF was 98% and 92% respectively. The ROC analysis disclosed that anti-CCP, compared to RF, provided the best combination of sensitivity and specificity for detecting either groups of RA. In addition, anti-CCP provided better complementary diagnostic effect for our RA patients when the results of opposite tests were negative (33% vs 11% in Gr I, and 29% vs 9% in Gr II) (p<0.001). Conclusion. The detection of anti-CCP in the diagnosis of patients with refractory RA and RA in remission showed higher sensitivity and specificity than RF assay.