Table 1.
Patient characteristics a
| Characteristics |
Symptom-free controls |
ACPA-negative arthralgia |
ACPA-negative RA |
|---|---|---|---|
| (n = 19) | (n = 64) | (n = 20) | |
| Mean age, yr (SD) |
46.2 (11.8) |
41.9 (14.3) |
58.7 (14.5) |
| Females, n (%) |
15 (78.9) |
46 (71.9) |
11 (55.0) |
| Positive family history of RA, n (%) |
N/A |
25 (39.1) |
4 (20.0) |
| Median symptom duration at time of inclusion, wk (IQR) |
N/A |
13.4 (8.4 to 26.4) |
17.6 (11.5 to 25.9) |
| Gradual symptom onset, n (%) |
N/A |
48 (75.0) |
12 (60.0) |
| Initial symptom localization, n (%) |
N/A |
|
|
| Upper extremities, n (%) |
|
47 (73.4) |
10 (50.0) |
| Lower extremities, n (%) |
|
2 (3.1) |
4 (20.0) |
| Upper and lower extremities, n (%) |
|
15 (23.4) |
6 (30.0) |
| Symmetrical localization, n (%) |
N/A |
46 (71.9) |
13 (65.0) |
| Median morning stiffness, min (IQR) |
N/A |
45 (15 to 90) |
120 (30 to 120) |
| Median tender joint count in 68 joints (IQR) |
0 |
5.5 (3 to 10.8) |
12 (4.8 to 17.8) |
| Median swollen joint count 66 joints (IQR) |
0 |
0 |
6 (4 to 11) |
| ACPA positivity (>7.0 IU/ml), n (%) |
N/A |
0 |
0 |
| IgM RF positivity (>3.5 IU/ml), n (%) |
N/A |
9 (14.1) |
3 (15.0) |
| Increased CRP level (>10 mg/L), n (%) | N/A | 10 (15.6) | 11 (55.0) |
aACPA, Anticitrullinated peptide antibody; CRP, C-reactive protein; IQR, Interquartile range; IgM RF, Immunoglobulin M rheumatoid factor; N/A, Not applicable; RA, Rheumatoid arthritis; SD, Standard deviation.