Long-term outcome of rheumatoid arthritis defined according to the 2010-classification criteria

The 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria for rheumatoid arthritis (RA) have been thoroughly studied for the test characteristics but it is unclear whether '2010 RA' has a different phenotype than '1987 RA' when assessing the severity of the disease course. Therefore this study compared two long-term disease outcomes.

1502 early arthritis patients that had no other diagnoses than RA or undifferentiated arthritis (UA) were studied on fulfilling the 1987 ACR criteria, 2010 criteria or both. The severity of joint damage was studied with yearly radiographs over 7 years. Achieving disease-modifying anti-rheumatic drug (DMARD)-free sustained remission was assessed over 10-years follow-up. Multivariate normal regression and Cox-proportional hazard regression were used, adjusting for age, gender and treatment.

550 patients fulfilled the 1987 criteria, 788 patients the 2010 criteria and 489 both criteria sets. Patients fulfilling the 2010 criteria developed less severe radiological joint damage (p=0.023) and achieved DMARD-free sustained remission more often (HR=1.18 (0.93-1.50)) than patients fulfilling the 1987 criteria, though the latter was not statistically significant. All 1987+2010- patients were anti-citrullinated peptide antibody (ACPA)-negative. When also applying the radiologic criterion of the 2010-criteria, half of the 1987+2010- patients became 2010 criteria positive, but results on the long-term outcome remained similar.

'2010 RA' has a milder disease course than '1987 RA'. This may have important implications for basic scientific studies and clinical trials in RA.