Background In 2010 the ACR/EULAR classification criteria for rheumatoid arthritis (RA) were proposed. They focus on features at earlier stages of disease that are associated with persistent and/or erosive disease, which may help to adapt treatment regimens on the basis of individual prognosis. The criteria have been applied in a large number of studies, but information on the relation with long-term outcome is scarce (1). Early intervention with DMARDs aims to reduce current disease activity and prevent structural damage. Based on clinical assessment, the Rheumatoid Arthritis Articular Damage (RAAD) scores 1 or 2 points for structural damage in 35 joints, resulting in a range from 0 to 70 (2). The RAAD score correlates strongly with radiographic damage in hands and feet, but is more comprehensive, including all joints that may be damaged by RA. It has been applied in various small studies.
Objectives To evaluate structural joint damage according to the RAAD score in RA patients with a disease duration of 5 years or longer and its relation to the ACR/EULAR 2010 classification criteria at baseline.
Methods In a large regional teaching hospital, the RAAD score is recorded annually by rheumatologists and nurses since 2014 as part of routine clinical assessment of disease activity in order to evaluate disease progression and quality of care. ACR/EULAR 2010 classification criteria and the presence of radiological erosion were obtained retrospectively from the patients' medical records. Statistical analyses were performed on the total group of patients, and stratified by disease duration (5–9 years versus 10 years or longer). Data were analysed using Spearman correlation and Mann-Whitney U tests.
Results The database consists of 1966 patients with a clinical diagnosis of RA. All patients were treated with s- and/or b-DMARDs. In January 2016, the RAAD-score had been performed at least once in 425 patients with a disease duration of at least 5 years. 68.5% of patients were female. At baseline, mean (SD) age was 64.1 (13.1) years, 78.4% were RF and/or anti-CCP positive and 73.2% scored 6 or higher on the ACR/EULAR 2010 classification criteria for RA. The median (IQR) disease duration at the time of assessing the RAAD score was 12.3 (7.8–19.6) years. The highest RAAD score was 55 and the median (IQR) in the total group was 2.0 (0.0–7.0). The correlation of the sum of the ACR/EULAR 2010 classification criteria at baseline and the RAAD score at follow-up was very weak (r=0.11, p=0.033). Table 1 presents the RAAD scores for individual ACR/EULAR 2010 classification criteria. Acute-phase reactants, higher number of affected joints and erosions at baseline resulted in higher RAAD scores.
Conclusions In a cohort of RA patients, the sum score of the ACR/EULAR 2010 classification criteria at baseline correlated weakly with long-term structural joint damage. The presence of erosions at baseline, not included in the criteria set, was the best predictor of a higher RAAD score.
Burgers LE, van Nies JAB, Ho LY et al. Long-term outcome of Rheumatoid arthritis defined according to the 2010-classification criteria. Ann Rheum Dis 2014;73:428–32.
Zijlstra TR, Bernelot Moens HJ, Bukhari MAS. The rheumatoid arthritis articular damage score: first steps in developing a clinical index of long term damage in RA. Ann Rheum Dis 2002;61:20–3.
Disclosure of Interest None declared