Comparison of baseline characteristics between mild UPA, progressive UPA, and the RA groups
| Baseline variables | Mild UPA† (n=45) | p Value mild v progressive UPA | Progressive UPA (n=32) | p Value progressive UPA v RA | RA‡ (n=203) |
|---|---|---|---|---|---|
| *p<0.05; **p<0.01; ***p<0.001 for differences between groups (Student's t test). | |||||
| †UPA, undifferentiated polyarthritis; ‡RA, rheumatoid arthritis. | |||||
| Age ((years) median (range)) | 45 (21–81) | ** | 53 (25–81) | 61 (18–90) | |
| Women (%) | 58 | 72 | 69 | ||
| Disease duration ((months) median (range)) | 3 (0–25) | * | 4 (0–36) | 4 (0–36) | |
| Arthritis gthree joints (%) | 47 | * | 72 | * | 92 |
| Symmetric arthritis (%) | 42 | 63 | ** | 87 | |
| Arthritis of hands (%) | 62 | ** | 91 | 97 | |
| Arthritis of small joints (PIP, MCP, MTP (%)) | 78 | 81 | 94 | ||
| Arthritis of large joints (knee, ankle, shoulder, elbow (%)) | 47 | 34 | 50 | ||
| IgM-RF positive (%) | 20 | 16 | *** | 51 | |
| CRP (mg/ml (mean (SD)) | 190 (270) | 140 (160) | *** | 340 (400) | |
| DAS28 score (mean (SD)) | 3.8 (1.5) | * | 4.4 (0.9) | *** | 5.2 (1.2) |
| Sharp/van der Heijde score (median (range)) | 2.0 (0–55) | * | 8.0 (0–58) | 5.0 (0–136) | |
| HAQ score (mean (SD)) | 0.6 (0.6) | 0.9 (0.6) | 1.1 (0.8) | ||