类风湿性关节炎新标准：侵蚀关节≥3个

柏林(EGMN)——美国风湿病学会(ACR)和欧洲抗风湿病联盟(ELARA)工作组在欧洲风湿病大会上指出，只要患者手足部位侵蚀关节≥3个，无论是否存在其他体征和症状，即可诊断为类风湿性关节炎(RA) (Ann. Rheum. Dis. 2012;71[Suppl3]:25)。

该项决定得到来自不同国家的18位工作组成员的一致认可，为重新定义RA分类工作画上了一个圆满句号。这项工作始于2010年发布的以体征和症状为主的新RA分类标准，该标准没有明确关节侵蚀放射影像学证据的作用(Arthritis Rheum. 2010;62:2569-81)。

工作组负责人、荷兰莱顿大学医学中心的Désirée van der Heijde博士在会议上指出，尽管放射影像学结果在ACR/EULAR分类标准中并非必须，但如果存在典型关节侵蚀，即使未能满足2010年RA分类标准评分系统要求，也可诊断为RA。对于很有可能被错误分类的疑似持续性、非活动性未分类关节炎患者，应进行放射影像学检查。另外一种常见的情况是，早期关节炎的患者在转诊之前已经进行了X线检查。采用新的侵蚀关节分类的关键前提是，由于单纯放射影像学证据即可确诊RA，侵蚀关节标准应具有非常高的特异性且假阳性率最低。敏感性不足并不是问题，因为患者还可以通过2010年标准进行RA分类。

为了解可准确分类RA的侵蚀关节数量，工作组对莱顿早期关节炎研究(902例患者)和法国ESPOIR研究(811例患者)的队列数据进行了综合分析，重点关注两个队列中未满足2010年RA分类标准的亚组患者，并探索侵蚀关节数量与能够确诊RA的3个结局发生率(甲氨蝶呤治疗1年、任何缓解病情抗风湿药物治疗1年或疾病持续5年)的相关性。他们发现3个结局的发生率均相似。

在ESPOIR队列中，达到疾病持续5年终点、侵蚀关节≥3个的患者发生RA的特异性和敏感性分别为91%和24%(侵蚀关节是指任何手足关节至少在1次影像学检查中可见皮质中断)。相反，以侵蚀关节≥2个作为阈值的特异性和敏感性分别为82%(目标敏感性为<90%)和30%。在莱顿研究队列中，侵蚀关节≥3个的特异性和敏感性分别为95%和15%，侵蚀关节≥2个的特异性和敏感性分别为91%和20%。

Heijde博士指出，部分风湿科医生或许对侵蚀关节≥3个的标准感到意外，他们认为单纯1个关节侵蚀对于RA分类已非常特异。但 对上述队列资料进行分析后发现，3个侵蚀关节应该是最佳临界值，工作组成员对此一致认同。此外，分析还表明，侵蚀关节≥3个的标准可控制阳性分类数量。在莱顿队列中，308例不符合2010年临床标准的入组者中有31例(10%)达到影像学阈值；在ESPOIR队列中，该比例为12%(18/147)。她强调，新的关节侵蚀分类标准不会新诊断出很多RA患者。明确RA分类定义非常重要，尤其对于不符合分类标准但具有严重侵蚀关节的患者而言。

英国切斯特菲尔德关节炎国立研究中心医学主任Alan Silman博士评论指出，关节侵蚀是RA的标志，如果患者关节发生侵蚀，就无需其他分类条件。最新结果表明，仅发生关节侵蚀的RA患者只是极少数，2010年标准可识别约90%的RA患者，本研究结果支持该分类标准。

van der Heijde 博士和 Silman博士均报告无相关利益冲突。

爱思唯尔  版权所有

BY MITCHEL L. ZOLER
Elsevier Global Medical News
Breaking News

BERLIN (EGMN)– Patients with at least three erosive joints in their hands and feet have rheumatoid arthritis regardless of whatever other signs and symptoms they may or may not have, according to a task force of the American College of Rheumatology and the European League Against Rheumatism (Ann. Rheum. Dis. 2012;71[Suppl3]:25).

This unanimous decision from the 18-member international task force closes the circle for redefining the classification of rheumatoid arthritis patients, a process that began with the 2010 release of a new signs and symptoms–driven rheumatoid arthritis (RA) classification that had no role for radiographic evidence of joint erosions (Arthritis Rheum. 2010;62:2569-81).

Although “radiographs are not required in the ACR/EULAR classification criteria, the presence of typical erosions allows classification of RA even without fulfillment of the [2010] scoring system,” task force leader Dr. Désirée van der Heijde said at the meeting. “Radiographs should be taken in an unclassified patient in whom long-standing, inactive disease is suspected, and is likely misclassified,” said Dr. van der Heijde, professor rheumatology at Leiden (the Netherlands) University Medical Center. Another common scenario is when a radiograph already exists for a patient who might have early arthritis because it was taken before rheumatologic referral.

The key premise of the new erosive-joint classification was that because radiographs alone could classify a patient as having RA, the erosive joint criteria had to be very specific and produce a minimal number of false positives. Lack of sensitivity was not an issue, as patients could also be classified with RA by the 2010 criteria.

To get a sense of how many erosive joints are needed to produce a reliable identification of RA, the task force studied data collected from two early-arthritis groups, the Early Arthritis Cohort assembled in Leiden with 902 patients, and the Etude et Suivi des Polyarthrites Indifferenciées Récentes (ESPOIR) cohort assembled in Montpellier, France with 811 patients. The task force focused on the subgroup of people in either cohort who did not meet the 2010 classification criteria for RA, and examined the link between various numbers of erosive joints in these people and the incidence of three outcomes the task force considered pathognomonic for RA: on methotrexate treatment after 1 year, on treatment with any disease-modifying antirheumatic drug after 1 year, or disease persistence for 5 years. They found that all three outcomes occurred at similar rates.

In the ESPOIR cohort, with the end point of 5-year disease persistence, people with at least three erosive joints developed RA with a specificity of 91% and a sensitivity of 24%. (An erosive joint was any hand or foot joint with at least one radiographic erosion visible as a cortical break.) In contrast, a threshold of at least two erosive joints carried a specificity of 82% – putting it below the 90% the task force sought – and a sensitivity of 30%. In the Leiden cohort, three or more erosive joints had a sensitivity of 95% and a sensitivity of 15%, while two or more joints was 91% specific and 20% sensitive.

“Some rheumatologists might be surprised [at the need for three erosive joints] because they think that just one erosion is very specific for RA. We showed that one erosion is not specific; you really need more to be very specific for RA,” she said in an interview. “After we saw the data it was very clear to us that three would be the right cutoff. It was a unanimous decision.”

It also turned out that a criterion of three or more erosive joints kept a lid on the number of positive classifications. In the Leiden cohort, 31 (10%) of the 308 enrollees who did not meet the 2010 clinical criteria met the radiographic threshold; in the ESPOIR cohort, 18 (12%) of 147 had at least three erosive joints.

“There will not be many patients who get classified,” based on their erosive joints, she noted. Despite that, “it’s very important to have this definition, because many people were asking for it. It’s important to have a clear definition. And it’s important for patients who do not meet the classification criteria but have several erosions.”

“Erosions are the hallmark of RA; if patients have erosions they don’t need anything else,” commented Dr. Alan Silman, medical director of Arthritis Research UK in Chesterfield, England. The new findings show “there are very few people with RA who just have erosions. The results support the classification criteria,” by showing that the 2010 criteria capture roughly 90% of all RA patients, he said in an interview.

Dr. van der Heijde and Dr. Silman said that they had no disclosures.