Table 1. Baseline demographic and clinical characteristics of the total population according to the presence of PsA.
| Variables | Total (n=209) | PsA* (n=29) | CASPAR-negative psoriasis(n=180) | p | |
|---|---|---|---|---|---|
| Age (yr) | 38 (29–50) | 39 (33–45) | 37 (29–52) | 0.802 | |
| Onset age (yr) | 26 (20–38) | 26 (20–37) | 26 (20–39) | 0.314 | |
| Disease duration (yr) | 9 (3–17) | 11 (5–20) | 9 (3–15) | 0.228 | |
| Sex (male) | 143 (68.4) | 21 (72.4) | 122 (67.8) | 0.777 | |
| Family history | 29 (13.9) | 5 (17.2) | 24 (13.3) | 0.565 | |
| Clinical characteristics | |||||
| Scalp involvement | 149 (71.3) | 23 (79.3) | 126 (70) | 0.419 | |
| Nail change | 123 (58.9) | 25 (86.2) | 98 (54.4) | 0.002 | |
| Peripheral arthritis | 31 (14.7) | 17 (58.6) | 14 (7.8) | <0.001 | |
| Axial arthritis | 30 (14.4) | 16 (55.2) | 14 (7.8) | <0.001 | |
| Enthesopathy | 11 (5.3) | 8 (27.6) | 3 (1.7) | <0.001 | |
| PsA | 29 (13.9) | ||||
| Peripheral type | 14 (6.7) | ||||
| Axial type | 10 (4.8) | ||||
| Both | 5 (2.4) | ||||
| HLA-B27 positivity | 18 (8.6) | 4 (13.8) | 14 (7.8) | 0.286 | |
| PASI score | 7.2 (3.6–11.3) | 10.2 (6.3–14.4) | 6.8 (3.3–11.0) | 0.011 | |
| Laboratory parameters | |||||
| ESR | 7 (2–15) | 11.5 (2.0–16.8) | 7 (2–15) | 0.216 | |
| RDW | 12.8 (12.2–13.3) | 13.1 (12.6–13.8) | 12.7 (12.1–13.3) | 0.017 | |
| CRP | 1.5 (0.8–3.7) | 3.9 (0.9–9.7) | 1.4 (0.8–3.5) | 0.025 | |
| Negative rheumatoid factor† | 200 (95.7) | 28 (96.6) | 172 (95.6) | 0.768 | |
Values are presented as median (interquartile range) or number (%).
PsA: psoriatic arthritis, CASPAR: Classification Criteria for Psoriatic Arthritis, PASI: psoriasis area and severity index, ESR: erythrocyte sedimentation rate, RDW: red cell distribution width, CRP: C-reactive protein.
*PsA was diagnosed according to the CASPAR criteria.
†Negative rheumatoid factor was defined as <15 IU/ml.