Table 1

Baseline characteristics of patients classified with rheumatoid arthritis (RA) according to either the 1987 and/or the 2010− criteria

Patient characteristic1987-RA (n=550)2010-RA (n=788)1987−/2010+ (n=299)1987+/2010+ (n=489)1987+/2010−(n=61)
Age at inclusion, years, mean±SD57.9±16.256.6±16.454.7±16.457.8±16.258.9±15.8
Female sex377 (68.5)536 (68.0)198 (66.2)338 (69.1)39 (63.9)
Symptom duration in weeks, median (IQR)21.9 (12.7–38.1)19.9 (10.6–37.3)*15.0 (5.9–31.3)22.0 (13.0–40.0)15.7 (10.8–31.8)
Symptom duration <12 weeks120 (23.5)221 (29.7)*119 (41.2)102 (22.4)18 (33.3)
Swollen joint count of 66 joints, median (IQR)10.0 (6.0–15.0)9.0 (4.0–15.0)4.0 (2.0–10.0)11.0 (7.0–16.0)6.0 (4.0–8.0)
Acute onset of symptoms287 (53.8)408 (53.5)159 (55.4)249 (52.3)38 (66.7)
Onset of symptoms in small joints306 (57.0)443 (57.2)170 (57.2)273 (57.1)33 (55.9)
Symmetric onset of symptoms377 (74.8)519 (71.8)183 (66.8)336 (74.8)41 (74.5)
RF positive307 (55.9)444 (56.5)138 (46.3)306 (62.7)1 (1.6)
ACPA positive264 (52.3)379 (52.1)115(41.7)264 (58.5)0 (0)
ESR, mm/h, mean±SD41.1±28.838.1±28.232.0±26.342.0±28.734.7±28.8
CRP, mg/l, median (IQR)19.0 (8.0–42.8)16.0(6.0–37.0)*12.0 (4.0–26.3)19.0 (9.0–43.0)19.0 (6.5–37.0)
Morning stiffness, minutes, median (IQR)90 (60–180)60 (30–120)*30 (10–82.5)90 (60–180)90 (60–150)
HAQ (0–3), median (IQR)1.0 (0.6–1.6)1.0 (0.5–1.5)0.8 (0.4–1.4)1.0 (0.6–1.6)0.9 (0.6–1.3)
Erosive joints, median (IQR)3 (1–7)3 (1–6)1.5 (0–4)4 (1–7)4 (1–6)
  • Unless indicated otherwise, values are the number (%) of patients.

  • Some data were missing: for symptom duration (n=48), for acute onset of symptoms (n=29), for symptom onset in small joints (n=15), for symmetric onset of symptoms (n=71), for RF (n=2), for antibodies to citrullinated protein antigen (ACPA) (n=68), for ESR (n=3), for CRP (n=35), for morning stiffness (n=24) and for HAQ (n=138).

  • *p<0.05 for comparison between 1987-RA and 2010-RA (Student t-test or Mann-Whitney U test as applicable).

  • ESR, erythrocyte sedimentation rate; HAQ, health assessment questionnaire; RF, rheumatoid factor; SD, standard error.