Table 1.
Baseline characteristics of arthralgia-patients included in the three cohorts, also stratified for ACPA status
| Characteristics | All arthralgia patients |
ACPA positive |
ACPA negative |
||||||
|---|---|---|---|---|---|---|---|---|---|
| Cohort 1 (n = 166) | Cohort 2 (n = 473) | Cohort 3 (n = 162) | Cohort 1 (n = 37) | Cohort 2 (n = 64) | Cohort 3 (n = 90) | Cohort 1 (n = 129) | Cohort 2 (n = 409) | Cohort 3 (n = 72) | |
| Age, years, mean (s.d.) | 45 (12) | 44 (13) | 51 (11) | 45 (11) | 48 (13) | 51 (11) | 45 (12) | 43 (13) | 52 (11) |
| Female, n (%) | 136 (82) | 366 (77) | 120 (74) | 32 (86) | 52 (81) | 67 (74) | 104 (81) | 314 (77) | 53 (74) |
| Symptom duration, weeks, median (IQR) | 29 (19–40) | 19 (9–44) | 57 (26–157) | 28 (17–40) | 24 (13–53) | 52 (26–137) | 29 (20–39) | 18 (9–41) | 83 (30–209) |
| TJC44, median (IQR) | 5 (3–8) | 5 (2–9) | 1 (0–5) | 4 (2–7) | 3 (1–7) | 1 (0–5) | 5 (3–8) | 5 (2–10) | 1 (0–5) |
| ACPA positivity, n (%) | 37 (22) | 64 (14) | 90 (56) | NA | NA | NA | NA | NA | NA |
| RF positivity, n (%) | 49 (30) | 95 (20) | 119 (74) | 22 (59) | 49 (77) | 47 (52) | 27 (21) | 46 (11) | 72 (100) |
| Increased CRP, n (%) | 39 (23) | 101 (22) | 12 (7) | 11 (30) | 20 (32) | 8 (9) | 28 (22) | 81 (20) | 4 (6) |
| Presence of local subclinical synovitisa, n (%) | 60 (36) | 193 (41) | 50 (31) | 13 (35) | 36 (56) | 31 (34) | 47 (36) | 157 (38) | 19 (26) |
a
Presence of US- (cohort 1 and cohort 3) or MRI- (cohort 2) detected subclinical synovitis. Joints screened for cohorts 1 and 2: MCP 2–5, radiocarpal, intercarpal, radioulnar (cohort 2) and MTP 2–5. Joints screened for cohort 3: MCP 2–3; MTP 2, 3 and 5 and wrist.
IQR: interquartile range; TJC44: 44-joint tender joint count; NA: not applicable.