Background The 2010 ACR/EULAR classification criteria for rheumatoid arthritis (2010 RA criteria) have made it possible to classify RA earlier. The criteria yield a score from 0-10 points, with the cut-off for definite RA set at ≥6 points. In general, diagnostic certainty increases with an increasing number of criteria points, and some patients with only 6 points may not have RA, but rather a self-limiting condition.
Objectives To study the 2-year outcome of patients with arthritis of less than 16 weeks duration fulfilling the 2010 RA criteria at study inclusion, according to the number of criteria points.
Methods 1118 patients (pts) (age 18-75 yrs) with inflammatory arthritis of ≤16 weeks duration were included in the NOR-VEAC (Norwegian Very Early Arthritis Clinic) study from 2004 to 2010, i.e. before the 2010 RA criteria were implemented. The 2010 RA criteria were retrospectively applied. We defined two outcome groups: Pts prescribed with DMARDs and pts who had one or more swollen joints or a clinical diagnosis of RA at last visit were defined as “persistent disease”, whereas pts with no DMARD use ever and no swollen joints at last visit were defined as “resolving arthritis”. Independent samples t-tests, Mann-Whitney-Wilcoxon tests or chi-square tests were used to compare outcome groups, as appropriate.
Results 261 of 1118 pts (21.6%) fulfilled the 2010 RA criteria at baseline. 254 of these had follow-up data, and were included in the current study. Duration of joint swelling [median (25-75 perc.)] was 63 (39-83) days, mean (SD) age 53 (14) yrs, 64% were females, 58% anti-CCP positive, and 70% anti-CCP and/or RF positive. 70 pts (27.6%) had 6 criteria points at baseline. The corresponding numbers for 7, 8, 9 and 10 points were 73 (28.7%), 43 (16.9%), 20 (7.9%) and 48 (18.9%). As expected, the majority (87.0%) of the pts fulfilling the 2010 RA criteria at baseline developed persistent disease. Nevertheless, in the group with only six criteria points, the arthritis resolved without DMARDs in 24.3% of the pts. Fewer pts with >6 points had resolving arthritis – 15.1%, 9.3%, 5.0% and 0.0% among pts with 7, 8, 9 and 10 points, respectively. Pts with resolving arthritis thus had significantly fewer criteria points than pts with persistent disease (median 6 vs 7, p=0.002) as well as lower frequency of anti-CCP positivity (12.1 vs 64.7%, p<0.0005), shorter duration of joint swelling (median 47 vs 65 days, p=0.001), less joint pain (mean 46.3 vs 56.6 mm, p=0.013) and lower proportion of ever smokers (51.5 vs 73.8%, p=0.014).
Conclusions The majority of the pts with arthritis of less than 16 weeks duration fulfilling the 2010 RA criteria at baseline had persistent disease, including all pts with 10 criteria points, but in a quarter of pts with only 6 criteria points the arthritis resolved without DMARDs. These results underline the importance of clinical judgment when making the diagnosis of RA, especially in early disease. If DMARD treatment is started in a patient with short disease duration and a somewhat uncertain RA diagnosis, a trial of DMARD discontinuation after a certain period of time should be considered to avoid overtreatment.
Disclosure of Interest None declared