Demographic data of the study participants
| Healthy controls n=8 | At risk individuals n=13 | Early arthritis patients n=14 | |
|---|---|---|---|
| Sex, female (%) | 5 (63) | 10 (77) | 9 (64) |
| Age (years) (median (IQR)) | 32 (28–44) | 48 (34–54) | 54 (34–60) |
| IgM-RF positive (n (%)) | 0 (0) | 5 (39) | 7 (50) |
| IgM-RF level* (kU/l) (median (IQR) | – | 265 (79–1049) | 120 (69–563) |
| ACPA positive (n (%)) | 0 (0) | 8 (62) | 7 (50) |
| ACPA level* (kAU/l) (median (IQR)) | – | 224 (136–685) | 678 (119–2443) |
| IgM-RF and ACPA both pos (n (%)) | 0 (0) | 0 (0) | 5 (36) |
| ESR (mm/h) (median (IQR)) | – | 7 (2–14)† | 12 (8–14) |
| CRP (mg/l) (median (IQR)) | 0.9 (0.5–4.4) | 1.6 (0.6–6.1) | 5.6 (1.1–14.4) |
| 68 TJC (n) (median (IQR)) | 0 (0) | 2 (1–5) | 13 (4–27) |
| 66 SJC (n) (median (IQR)) | 0 (0) | 0 (0) | 7 (4–11) |
Categorical variables: n (%). Continuous variables (data not normally distributed): median (IQR).
*Levels only in positive patients.
†Level missing from one individual.
ACPA, anticitrullinated protein antibodies; ESR, erythrocyte sedimentation rate; CRP, C-reactive protein; IgM-RF, IgM rheumatoid factor; 68 TJC, tender joint count of 68 joints; 66 SJC, swollen joint count of 66 joints.