Demographic and clinical data for the different patient groups who underwent a scintigraphy examination for the evaluation of sacroiliitis. In the patient group with axial SpA, patients with AS and patients with nonradiographic axial SpA are pooled.
| Characteristic | AS | Nonradiographic Axial SpA | Axial SpA (pooled AS plus nonradiographic SpA) | Controls |
|---|---|---|---|---|
| No. of patients | 56 | 41 | 97 | 97 |
| Men, % | 67.9 | 46.3 | 58.8 | 44.4 |
| Mean age, yrs (SD) | 39.3 (12.8) | 35.1 (10.2) | 37.5 (11.9) | 42.8 (13.2) |
| Mean disease duration, yrs (SD) | 11.6 (9.2) | 6.7 (6.5) | 9.6 (8.5) | 9.6 (10.1) |
| % HLA-B27-positive | 85.7 | 75.0 | 80.4 | 34.0* |
| BASDAI, mean (SD) | 4.4 (2.3) | 4.2 (2.3) | 4.3 (2.3) | 4.2 (1.7) |
| BASFI, mean (SD) | 3.3 (2.3) | 3.3 (2.3) | 3.3 (2.4) | 3.3 (2.2) |
↵* The high percentage of HLA-B27-positive controls occurred because HLA-B27 was one of the referral measurements2.