Baseline characteristics of all CZP patients
| Overall axSpA N=315 | AS n=174 | nr-axSpA n=141 | |
| Mean age, years (SD) | 39.7 (12.0) | 41.5 (11.7) | 37.5 (11.9) |
| Male, % | 62.2 | 73.0 | 48.9 |
| Symptom duration, years, median (min, max) | 7.8 (0.3, 50.9) | 9.1 (0.3, 50.9) | 5.8 (0.3, 41.5) |
| CRP, mg/L, median (min, max) | 13.4 (0.1, 174.8) | 14.2 (0.1, 174.8) | 12.0 (0.1, 156.2) |
| Patients with elevated CRP (>15 mg/L), % | 40.6 | 43.7 | 36.9 |
| BASDAI, mean (SD) | 6.4 (1.5) | 6.4 (1.6) | 6.5 (1.5) |
| BASFI, mean (SD) | 5.4 (2.3) n=314 | 5.7 (2.2) | 4.9 (2.3) n=140 |
| BASMI linear, mean (SD) | 3.8 (1.7) | 4.4 (1.7) | 3.1 (1.5) |
| ASDAS, mean (SD) | 3.9 (0.9) n=313 | 3.9 (0.9) | 3.8 (0.8) n=139 |
| Spinal radiographs | |||
| mSASSS | |||
| Mean (SD)* | 9.5 (16.1) | 13.2 (18.2) | 4.4 (11.0) |
| Median | 1.5 n=190 | 3.0 n=110 | 0.0 n=80 |
| Patients with ≥1 bridging or non-bridging syndesmophyte at baseline, n (%) | 63 (33.2) | 47 (42.7) | 16 (20.0) |
| MRI set | n=158 | n=92 | n=66 |
| SPARCC (SI joints) | |||
| Mean (95% CI)* | 8.1 (6.1, 10.2) | 8.5 (5.6, 11.4) | 7.5 (4.4, 10.6) |
| Median | 2.0 n=151 | 1.0 n=91 | 3.0 n=60 |
| Patients with MRI inflammation (SPARCC ≥2), estimate, % | 51.2 | 47.0 | 57.3 |
| Berlin score (spine) | |||
| Mean (95% CI)* | 6.2 (4.8, 7.5), n=157 | 7.4 (5.6, 9.2) | 4.4 (2.4, 6.5), n=65 |
| Median | 2.0 n=153 | 4.3 | 0.5 n=61 |
| Patients with MRI inflammation (Berlin >2) estimate, % | 50.4 n=157 | 57.6 | 40.1 n=65 |
*Least squares mean scores were estimated using mixed-model for repeated measures analyses. Inflammation was defined as Berlin >2 or SPARCC ≥2. Data are presented for all patients who received ≥1 dose CZP at any point in the trial. To define AS and nr-axSpA subpopulations, the most recent SI joint X-rays (performed ≤12 months prior to screening) were locally read to determine the presence/absence of radiographic sacroiliitis.
AS, ankylosing spondylitis; ASDAS, Ankylosing Spondylitis Disease Activity Score; axSpA, axial spondyloarthritis; BASDAI, Bath Ankylosing Spondylitis Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; BASMI, Bath Ankylosing Spondylitis Metrology Index; CRP, C-reactive protein; CZP, certolizumab pegol; mSASSS, modified Stoke Ankylosing Spondylitis Spine Score; nr, non-radiographic; SI, sacroiliac; SPARCC, Spondyloarthritis Research Consortium of Canada.