Table 1

Baseline characteristics cohort 1 and cohort 2

NCohort 1 (n=407)NCohort 2 (n=416)
Age at symptom onset (years)40753 (43–64)41657 (48–69)
Gender (female)407250 (61%)416269 (65%)
Baseline visit
 Symptom duration (months)4075.4 (3.0–10.0)4166.7 (4.5–11.4)
 RA (1987 ACR criteria)407255 (62.7%)416220 (52.9%)
 No of swollen joints4077 (3–14)4163 (1–7)
 No of tender joints4077 (2–14)4163 (0–8)
 CRP (mg/L)33610 (2–27)36312 (4–26)
 DAS28(3)CRP3364.5 (3.5–5.5)3633.7 (2.8–4.7)
 HAQ score3981.0 (0.5–1.6)4081.0 (0.5–1.8)
 RF (positive)368160 (43.5%)371155 (41.8%)
 ACPA (positive)288130 (45.1%)341136 (39.9%)
 SE (no of alleles)
  0351115 (32.8%)371135 (36.4%)
  1170 (48.4%)178 (48.0%)
  266 (18.8%)58 (15.6%)
 Previous or current DMARD use407142 (34%)416269 (65%)
 Previous or current steroid use40729 (7%)416130 (31%)
 Smoking
  Never smoked407129 (31.7%)377113 (30.0%)
  Ex-smoker162 (39.8%)166 (44.0%)
  Current smoker116 (28.5%)98 (26.0%)
  • Patients in cohort 1 were recruited between 1990 and 1994 and patients in cohort 2 were recruited between 2000 and 2004. Values are median (IQR) for continuous variables and numbers (%) for categorical variables.

    ACPA, anti-citrullinated protein antibody; ACR, American College of Rheumatology; CRP, C-reactive protein; DAS28(3)CRP, 28-joint disease activity score based on three components including CRP; DMARD, disease-modifying antirheumatic drug; HAQ, health assessment questionnaire; RA, rheumatoid arthritis; RF, rheumatoid factor; SE, shared epitope.