Demographics and baseline disease characteristics
| Characteristics | Patients with MRI scans (n=185) | Full mITT population (n=215) | ||
| ETN, n=88 | PBO, n=97 | ETN, n=106 | PBO, n=109 | |
| Age, years | 31.7 (7.8) | 32.2 (7.9) | 31.9 (7.8) | 32.0 (7.8) |
| Male, n (%) | 58 (65.9) | 54 (55.7) | 68 (64.2) | 62 (56.9) |
| White, n (%) | 68 (77.3) | 71 (73.2) | 79 (74.5) | 79 (72.5) |
| Symptom duration, years | 2.5 (2.0) | 2.4 (1.5) | 2.4 (1.9) | 2.5 (1.8) |
| Concomitant DMARD use, n (%) | 19 (21.6) | 20 (20.6) | 21 (19.8) | 21 (19.3) |
| Family history of SpA, n (%) | 26 (29.6) | 21 (21.7) | 28 (26.4) | 23 (21.1) |
| ASDAS-CRP | 3.0 (0.9) | 2.9 (1.0) | 3.0 (0.9) | 3.0 (1.0) |
| BASDAI (0–10) | 5.9 (1.8) | 6.0 (1.9) | 6.0 (1.8) | 6.0 (1.9) |
| Total back pain (0–10 cm VAS) | 5.5 (2.5) | 5.4 (2.3) | 5.5 (2.4) | 5.5 (2.4) |
| BASFI (0–10 cm VAS) | 4.2 (2.5) | 3.8 (2.5) | 4.2 (2.5) | 3.9 (2.5) |
| CRP, mg/L | 7.4 (11.2) | 6.3 (10.7) | 6.8 (10.6) | 6.4 (10.5) |
| CRP>3 mg/L, n (%) | 44 (50.0) | 39 (40.2) | 48 (45.3) | 44 (40.4) |
| HLA-B27 positive, n (%) | 60 (68.2) | 73 (75.3) | 72 (67.9) | 83 (76.2) |
| MRI sacroiliitis positive*, n (%) | 74 (84.1) | 78 (80.4) | 87 (82.1) | 87 (79.8) |
| MRI sacroiliitis positive* or CRP>3 mg/dL, n (%) | 80 (90.9) | 85 (87.6) | 94 (88.7) | 95 (87.2) |
| SPARCC MRI SIJ score (0–72) | 8.3 (10.1) | 7.7 (10.1) | 8.0 (9.7) | 7.7 (10.1) |
| SPARCC MRI spine 23-DVU score (0–414) | 5.5 (9.7) | 3.9 (7.2) | 5.2 (9.3) | 3.8 (7.0) |
All values are mean (SD) unless otherwise noted.
*Baseline MRIs were read by a central imaging reader for the presence of sacroiliitis according to ASAS definition.12
ASAS, Assessment of SpondyloArthritis International Society; ASDAS, Ankylosing Spondylitis Disease Activity Score; BASFI, Bath Ankylosing Spondylitis Functional Index; CRP, C-reactive protein; DMARD, disease-modifying antirheumatic drug; DVU, discovertebral unit; ETN, etanercept; HLA, human leucocyte antigen; mITT, modified intent-to-treat; PBO, placebo; SIJ, sacroiliac joint; SpA, spondyloarthritis; SPARCC, Spondyloarthritis Research Consortium of Canada; VAS, visual analogue scale.