Table 1.
Demographic and clinical characteristics of the study subjects*
| Healthy controls (n = 7) | Individuals at risk of RA (n = 12) | RA patients (n = 12) | |
|---|---|---|---|
| Sex, no. (%) female | 5 (71) | 8 (67) | 10 (83) |
| Age, years | 31 (28–40) | 44 (34–54) | 54 (35–60) |
| IgM‐RF positive, no. (%) | 0 (0) | 5 (42) | 9 (75) |
| IgM‐RF level, kU/liter | 1 (1–1) | 19 (4–144) | 79 (17–434) |
| ACPA positive, no. (%) | 0 (0) | 7 (58) | 7 (58) |
| ACPA level, kAU/liter | 3 (1–4) | 97 (3–389) | 81 (1–686) |
| ESR, mm/hour | – | 5.0 (2.0–8.0) | 13 (9.3–21) |
| CRP, mg/liter | 0.6 (0.3–1.4) | 1.9 (0.6–5.7) | 6.4 (1.1–21.2) |
| Tender joint count (28 joints assessed) | – | 2 (1–2) | 4 (1–21) |
| Swollen joint count (28 joints assessed) | – | 0 (0) | 8 (4–10) |
| DAS28 | – | – | 4.9 (3.9–5.9) |
a
Except where indicated otherwise, values are the median (interquartile range). RA = rheumatoid arthritis; IgM‐RF = IgM rheumatoid factor; ACPA = anti–citrullinated protein antibody; ESR = erythrocyte sedimentation rate; CRP = C‐reactive protein; DAS28 = Disease Activity Score in 28 joints.