| Characteristic | Adalimumab 40 mg weekly (N = 72) | Adalimumab 40 mg every other week (N = 239) |
| Male, n (%) | 46 (63.9) | 187 (78.2) |
| White, n (%) | 69 (95.8) | 230 (96.2) |
| Age, years (SD) | 46.1 (10.0) | 41.2 (11.8) |
| Disease duration, years (SD) | 10.7 (9.0) | 11.1 (9.6) |
| HLA-B27 positive, n (%) | 52 (72.2) | 193 (80.8) |
| Patient’s global assessment of disease activity, cm (SD) | 7.0 (2.1) | 6.2 (2.1) |
| Total back pain, cm (SD) | 7.2 (2.0) | 6.3 (2.1) |
| Inflammation (mean of questions 5 and 6 of the BASDAI), cm (SD) | 7.3 (1.9) | 6.5 (2.0) |
| BASFI, cm (SD) | 6.1 (2.3) | 5.2 (2.1) |
| BASDAI, cm (SD) | 6.9 (1.6) | 6.1 (1.7) |
| C-reactive protein, mg/dl (SD)† | 1.5 (1.6) | 2.0 (2.7) |
| BASMI, 0–10 (SD) | 4.5 (2.1) | 3.8 (2.2) |
| Chest expansion, cm (SD) | 2.9 (1.5) | 3.4 (1.9) |
| MASES, 0–13 (SD) | 8.4 (7.6) | 5.9 (6.7) |
*Values are mean (SD) unless otherwise noted. †Normal range using an ultrasensitive C-reactive protein assay is 0.007–0.49 mg/dl. BASDAI, Bath Ankylosing Spondylitis Disease activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; BASMI, Bath Ankylosing Spondylitis Metrology Index; MASES, Maastricht Ankylosing Spondylitis Enthesitis Score.