Improved RA classification among early arthritis patients with the concordant presence of three RA autoantibodies: analysis in two early arthritis clinics

Cristina Regueiro,Alejandro Balsa,Antonio Gonzalez,Isidoro González-Alvaro,Ana M Ortiz,Lorena Rodríguez-Martínez,Alejandro Villalba,Dora Pascual-Salcedo,Laura Nuño,Ana Martínez-Feito

doi:10.1186/s13075-019-2079-4

Abstract

BackgroundThe patients with RA benefit from early identification soon after the first clinical symptoms appear. The 2010 ACR/EULAR classification criteria were developed to fulfill this need and their application has been demonstrated to be effective. However, there is still room for improvement. Therefore, we aimed to evaluate the potential of the concordant presence of RF, anti-CCP and anti-carbamylated protein antibodies to improve current RA classification among early arthritis (EA) patients.MethodsData from the first visit of 1057 patients in two EA prospective cohorts were used. The serological scores from the 2010 ACR/EULAR criteria and the concordant presence of the three RA autoantibodies were assessed relative to a gold standard consisting of the RA classification with the 1987 ACR criteria at the 2 years of follow-up.ResultsThe concordant presence of three antibodies showed predictive characteristics allowing for direct classification as RA (positive predictive value = 96.1% and OR = 80.9). They were significantly better than the corresponding to the high antibody titers defined as in the 2010 classification criteria (PPV = 88.8%, OR = 26.1). In addition, the concordant presence of two antibodies was also very informative (PPV = 82.3%, OR = 15.1). These results allowed devising a scoring system based only on antibody concordance that displayed similar overall performance as the serological scoring system of the 2010 criteria. However, the best classification was obtained combining the concordance and 2010 serological systems, a combination with a significant contribution from each of the two systems.DiscussionThe concordant presence of RA autoantibodies showed an independent contribution to the classification of EA patients that permitted increased discrimination and precision.

Highlights

The patients with Rheumatoid arthritis (RA) benefit from early identification soon after the first clinical symptoms appear
The 1057 early arthritis (EA) patients were stratified according to the serological component of the 2010 American College of Rheumatology (ACR)/EULAR classification [2], or according to the presence of three, two, one, or none of the RA autoantibodies (Table 1)
Analysis of the EA patient strata showed that the highest positive predictive values (PPV) were obtained with the concordance criteria (Table 2), both in the top and the medium levels corresponding to the concordance of 3 (3Ab) and 2 (2Ab) antibodies, respectively

Summary

Introduction

The patients with RA benefit from early identification soon after the first clinical symptoms appear. We aimed to evaluate the potential of the concordant presence of RF, anti-CCP and anti-carbamylated protein antibodies to improve current RA classification among early arthritis (EA) patients. The classification criteria for RA were modified in 2010 by the ACR and the EULAR to include patients in the early phases of the disease [2]. Other autoantibodies, including the anti-carbamylated protein antibodies (ACarPA), have been assessed, but none has significantly improved the classification obtained with RF and anti-CCP antibodies [5,6,7]. None of these evaluations has assessed the value of the concordant presence of the RA antibodies as a classifier. We analyzed the data of the 1057 patients from the two Spanish EA cohorts included in Regueiro et al [6] to assess the value of new criteria considering antibody concordance

Objectives

Methods

Results

Discussion

Conclusion