Characteristics of the study population.
| Characteristic | N = 272 |
|---|---|
| Sex, % females (no.) | 56 (153) |
| Mean age, yrs (SD) | 44.6 (11) |
| Mean disease duration, yrs (SD) | 17.3 (11.6) |
| Inflammatory back pain, % (no. positive/no. tested) | 98.8 (240/243) |
| Peripheral arthritis, % (no. positive/no. tested) | 31 (73/239) |
| Enthesitis, % (no. positive/no. tested) | 66 (160/241) |
| Dactyliitis, % (no. positive/no. tested) | 20 (47/241) |
| History of uveitis, % (no. positive/no. tested) | 31 (74/240) |
| History of psoriasis, % (no. positive/no. tested) | 32 (78/243) |
| History of IBD, % (no. positive/no. tested) | 9 (21/239) |
| HLA-B27-positive, % (no. positive/no. tested) | 75 (146/194) |
| Radiographic sacroiliitis, % (no. positive/no. tested)* | 54.3 (113/208) |
| ASAS axial criteria, % (no. positive/no. tested) | 88 (196/222) |
| ASAS peripheral criteria, % (no. positive/no. tested) | 6 (14/222) |
↵* Definite radiographic sacroiliitis defined according to the modified New York criteria11 as sacroiliitis ≥ grade II bilateral or III unilateral. IBD: inflammatory bowel disease; ASAS: Assessment of Spondyloarthritis International Society.