Silveira I G, Burlingame R W, von Mühlen C A, Bender A L, Staub H L
Rheumatology Department, Sao Lucas Hospital, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.
Clin Rheumatol. 2007 Nov;26(11):1883-9. doi: 10.1007/s10067-007-0601-6. Epub 2007 Apr 5.
To compare the diagnostic powers of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) in a population selected for its high statistical relevance, over a 6-month period, an informed consent to test for anti-CCP was obtained from 1,025 consecutive patients for whom RF was ordered at a University laboratory. Within 1 year, a diagnosis was obtained without informing the physician about the anti-CCP result. Extensive statistical analyses were performed. A total of 768 patients satisfied the inclusion criteria, and 132 were classified as having RA, yielding a pre-test probability of RA of 17%. The sensitivities for anti-CCP and RF were 62 and 64% (P = 0.83), and the specificities were 97 and 90% (P < 0.001), respectively. The positive predictive value (PPV) was 79% for anti-CCP and 56% for RF (P < 0.001), whereas the negative predictive value was 92% for both. The likelihood ratio (LR) was 17.9 for anti-CCP and 6.2 for RF (P < 0.005). Forty RA patients were diagnosed with RA of less than 2 years length, and the same significant statistic differences between anti-CCP and RF were observed. Placing the results of both tests together, or using different cutoff points, increased the diagnostic utility of the tests. The anti-CCP test has statistically shown significant higher specificity, PPV, and LR for RA than the RF test in a clinically diverse population. If new criteria are to be devised to help diagnose early RA, anti-CCP should be included because it has a greater diagnostic impact than RF.
为了比较类风湿因子（RF）和抗环瓜氨酸肽（CCP）在一个具有高统计学相关性的人群中的诊断能力，在6个月的时间里，从一所大学实验室连续1025例接受RF检测的患者中获得了检测抗CCP的知情同意书。在1年内，在未告知医生抗CCP结果的情况下获得了诊断。进行了广泛的统计分析。共有768例患者符合纳入标准，其中132例被分类为患有类风湿关节炎（RA），RA的预测试概率为17%。抗CCP和RF的敏感性分别为62%和64%（P = 0.83），特异性分别为97%和90%（P < 0.001）。抗CCP的阳性预测值（PPV）为79%，RF为56%（P < 0.001），而两者的阴性预测值均为92%。抗CCP的似然比（LR）为17.9，RF为6.2（P < 0.005）。40例RA患者被诊断为病程小于2年的RA，抗CCP和RF之间观察到相同的显著统计学差异。将两种检测结果放在一起，或使用不同的临界值，可提高检测的诊断效用。在临床多样化的人群中，抗CCP检测在统计学上显示出对RA的特异性、PPV和LR显著高于RF检测。如果要制定新的标准来帮助早期诊断RA，应纳入抗CCP，因为它比RF具有更大的诊断影响力。
