title: Clinical features and independent predictors in the further development of rheumatoid arthritis in undifferentiated arthritis.
abstract: This study aims to investigate the prognosis of undifferentiated arthritis (UA) and to estimate the putative predictors contributing to predict the development of UA into rheumatoid arthritis (RA); thus, it could improve appropriate medical intervention. A retrospective cohort study of 218 patients with an initial diagnosis of UA and 2-year follow-up monitoring was carried out. The baseline information including demographic variables, clinical features, and laboratory data was collected. A logistic regression model was used for the statistical analysis. After 2 years of follow-up, 20.18% of UA patients evolved into RA, but 33.03% remained undifferentiated. Meanwhile, 25.23% went into remission, and 21.56% developed into other connective tissue diseases. Univariate and multivariate analysis showed that the titer of antibodies to cyclic citrullinated peptide (anti-CCP), tender joint count and duration of morning stiffness were independent predictors for the development of RA. The area under the curve (AUC) of duration of morning stiffness (0.81) was largest, followed by tender joint count (0.74). The AUC of anti-CCP antibodies (0.68) was higher than that of rheumatoid factor of IgM type (IgM-RF) (0.60), and the combination of these two antibodies was significantly higher than each alone (P < 0.001). In conclusion, UA patients had variable clinical outcomes and prognosis. Only the titer of anti-CCP antibodies, tender joint count, and duration of morning stiffness, instead of IgM-RF, could predict the development of RA. Although the anti-CCP antibody was better than the IgM-RF in predicting RA, a combined detection of them still improved the diagnostic performance.
authors.affiliation: Department of Rheumatology and Clinical Immunology, The First Affiliated Hospital of Sun Yat-Sen University, No. 58, Zhongshan 2nd Road, Guangzhou, 510080, China.
authors.forename: Dongying
authors.initials: D
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.forename: Liuqin
authors.initials: L
authors.lastname: Liang
authors.forename: Youjun
authors.initials: Y
authors.lastname: Xiao
authors.forename: Ting
authors.initials: T
authors.lastname: Xu
authors.forename: Qian
authors.initials: Q
authors.lastname: Qiu
authors.forename: Fan
authors.initials: F
authors.lastname: Lian
authors.forename: Zhongping
authors.initials: Z
authors.lastname: Zhan
authors.forename: Yujin
authors.initials: Y
authors.lastname: Ye
authors.forename: Hanshi
authors.initials: H
authors.lastname: Xu
authors.forename: Xiuyan
authors.initials: X
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012217:Rheumatoid Factor / Q000097:blood*; D012680:Sensitivity and Specificity
chemical_list: D001323:Autoantibodies; D012217:Rheumatoid Factor