Clinical baseline characteristics of and differences between patients diagnosed as rheumatoid arthritis (RA), ‘undifferentiated arthritis’ (UA) or ‘other’
| Patients included in analysis | ||||
|---|---|---|---|---|
| Characteristics | RA (n=144) | UA (n=98) | Other diagnoses (n=61) | All (n=303) |
| Gender | ||||
| Female, n (%) | 109 (75.7) | 80 (81.6) | 39 (63.9) | 228 (75.2) |
| Age, years, mean±SD | 50.53±14.86 | 41.59±16.2**,*** | 50.92±18.0 | 47.72±16.47 |
| Disease duration, days, median (IQR) | 70 (38.5;97.0) | 43(18.0;78.0)** | 49 (24;75)* | 57 (30;88) |
| SJC (66/68), median (IQR) | 8 (4;13) | 3 (2;8)** | 4 (2;8)** | 5 (2;11) |
| TJC(66/68), median (IQR) | 15 (8;22) | 5 (2;8)** | 7.5 (2;16)** | 10 (3;19) |
| CRP, mg/dl, median (IQR) | 1.2 (0.32;3.59) | 0.75 (0.3;2.65) | 0,82 (0.31;2.6) | 1.0 (0.31;2.83) |
| ESR, mm/h, median (IQR) | 28.5 (14;44.0) | 18 (8;44.0) | 30.0 (12;50) | 25 (12.0;45.5) |
| RF positive, n (%) | 65 (45.1) | 7 (7.1)** | 6 (9,8)** | 78 (25.7) |
| ACPA positive, n (%) | 61 (42.4) | 4 (4.1)** | 1 (1.6)** | 66 (21.8) |
| DAS28, mean±SD | 5.53±1.27 | 4.30±1.29** | 4.60±1.37** | 4.95±0.61 |
Significance level was set at 0.006 to correct for multiple comparisons.
*p<0.001 compared to patients with RA.
**p<0.0001 compared to patients with RA.
***p<0.006 compared to patients with other diagnoses.
Intergroup differences were analysed by analysis of variance (ANOVA) (multiple groups) and Kruskal-Wallis-test (pairwise comparisons in case of significant results in ANOVA).
ACPA, anti-citrullinated peptide antibodies; CRP, C-reactive protein; DAS28, Disease activity score (28 joints); ESR, erythrocyte sedimentation rate; RF, Rheumatoid factor; SJC, swollen joint count; TJC, tender joint count.