Department of Rheumatology, Leiden University Medical Center, Leiden, Netherlands.
Department of Rheumatology, Leiden University Medical Center, Leiden, Netherlands.
Semin Arthritis Rheum. 2023 Dec;63:152251. doi: 10.1016/j.semarthrit.2023.152251. Epub 2023 Aug 9.
Undifferentiated arthritis(UA) is clinically heterogeneous and differs in outcomes ranging from spontaneous resolution to RA-development. Therefore, we hypothesized that subgroups exist within UA and we aimed to identify homogeneous groups based on clinical features, and thereafter to relate these groups to the outcomes spontaneous resolution and RA-development. These outcomes can only be studied in UA-patients in which DMARD-treatment does not influence the natural disease course; these cohorts are scarce.
We studied autoantibody-negative UA-patients (not fulfilling 1987/2010 RA-criteria, no alternate diagnosis), included in the Leiden Early Arthritis Clinic between 1993 and 2006, when early DMARD-treatment in UA was infrequent. Latent class analysis was used to identify subgroups based on combinations of clinical features. Within these subgroups, test-characteristics were assessed for spontaneous resolution of arthritis and RA-development within 1 year.
310 consecutive UA-patients were studied. Five classes were identified: location and number of swollen joints were most distinguishing. Classes were characterized by: 1) polyarthritis, often symmetric; 2) oligoarthritis, frequently with subacute onset; 3) wrist-monoarthritis, often with subacute onset, increased BMI and without morning stiffness; 4) small-joint monoarthritis, often without increased acute phase reactants, and 5) large-joint monoarthritis, often with subacute onset. Studying the classes in relation to the outcomes revealed that patients without spontaneous resolution (thus having persistent disease) were nearly absent in the classes characterized by monoarthritis (specificity >90%). Additionally, patients who developed RA were infrequent in monoarthritis classes (sensitivity <7%).
Using a data-driven unsupervised approach, five subgroups within contemporary UA were identified. These have differences in the natural course of disease.
未分化关节炎（UA）临床表现具有异质性，其结局差异较大，从自发性缓解到发展为类风湿关节炎（RA）不等。因此，我们假设在 UA 中存在亚组，我们旨在根据临床特征确定同质组，然后将这些组与自发性缓解和 RA 发展的结局相关联。这些结局只能在未接受 DMARD 治疗的 UA 患者中进行研究，因为 DMARD 治疗会影响疾病自然病程；此类队列较为稀缺。
我们研究了自身抗体阴性的 UA 患者（不符合 1987/2010 年 RA 标准，无其他诊断），这些患者于 1993 年至 2006 年期间纳入莱顿早期关节炎诊所，当时 UA 中早期 DMARD 治疗并不常见。采用潜在类别分析根据临床特征的组合确定亚组。在这些亚组中，评估了关节炎自发性缓解和 1 年内 RA 发展的测试特征。
研究了 310 例连续的 UA 患者。确定了 5 个类别：肿胀关节的部位和数量是最具鉴别性的。这些类别具有以下特征：1）多关节炎，常为对称性；2）少关节炎，常为亚急性起病；3）腕关节单关节炎，常为亚急性起病，BMI 增加且无晨僵；4）小关节单关节炎，常无急性时相反应物增加，和 5）大关节单关节炎，常为亚急性起病。研究这些类别与结局的关系表明，没有自发性缓解（因此持续性疾病）的患者在以单关节炎为特征的类别中几乎不存在（特异性>90%）。此外，在单关节炎类别中，发展为 RA 的患者并不常见（敏感性<7%）。
使用数据驱动的无监督方法，在当代 UA 中确定了 5 个亚组。这些亚组在疾病自然病程方面存在差异。
