Table 1 Baseline characteristics of the 274 included patients with rheumatoid arthritis.
| All patients with RA (n = 274) | Anti‐CII‐negative patients with RA (n = 250) | Anti‐CII positive (>29 AU/ml) patients with RA (n = 24) | p Value (between anti‐CII negative and all anti‐CII positive patients) | Anti‐CII highly positive (>470 AU/ml) patients with RA (n = 9) | p Value (between anti‐CII negative and highly anti‐CII positive patients) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean age at inclusion (years) | 56 | 55.8 | 59.4 | NS | 63.3 | NS | |||||
| Females (%) | 70 (193/274) | 70 (176/250) | 71 (17/24) | NS | 67 (6/9) | NS | |||||
| Mean disease duration at inclusion (months) | 5.8 | 5.8 | 4.2 | 0.007 | 4.4 | NS | |||||
| RF positive (%; number positive/total number) | 63 (172/272) | 64 (160/249) | 52 (12/23) | NS | 56 (5/9) | NS | |||||
| Anti‐CP positive (%; number positive/total number) | 57 (157/274) | 59 (148/250) | 37.5 (9/24) | 0.040 | 33 (3/9) | NS | |||||
| CRP (mg/l) | 24 | 21 | 53 | <0.001 | 46 | 0.001 | |||||
| ESR (mm/h) | 28 | 27 | 36 | 0.046 | 41 | 0.005 | |||||
| Physician's assessment of disease activity (0–4) | 2.1 | 2.1 | 2.3 | NS | 2.4 | NS | |||||
| Number of swollen joints | 9 | 9 | 12 | NS (0.071) | 10 | NS | |||||
| Number of tender joints | 8 | 8 | 8 | NS | 8 | NS | |||||
| DAS28 | 5 | 5 | 5.2 | NS | 5.5 | NS | |||||
| Global VAS | 43 | 44 | 39 | NS | 46 | NS | |||||
| Pain VAS | 45 | 45 | 38 | NS | 37 | NS | |||||
| HAQ | 0.98 | 0.98 | 1.02 | NS | 1.33 | NS | |||||
| Patients starting DMARD treatment at baseline (%) | 84 (230/274) | 84 (210/250) | 83 (20/24) | NS | 89 (8/9) | NS |
AU, arbitrary unit; CII, collagen type II; CP, citrullinated protein/peptide; CRP, C reactive protein; DAS, disease activity score; DMARD, disease‐modifying antirheumatic disease; ESR, erythrocyte sedimentation rate; HAQ, Health Assessment Questionnaire; RA, rheumatoid arthritis; RF, rheumatoid factor; VAS, Visual Analogue Scale.
Values are given as mean values and as percentages (ratios).
Differences between anti‐CII‐negative and anti‐CII‐positive patients were analysed using unpaired t tests, whereas differences between proportions were analysed using the χ2 test or Fisher's exact test. Data for anti‐citrullinated protein/peptide measured as cyclic citrullinated peptide antibodies have been published earlier.9 Data for rheumatoid factor at the time of diagnosis are missing for two patients.