Patient demographics and baseline characteristics stratified by 2009 and preliminary 2021 MRI cut-offs for inflammatory lesions
| 2009 MRI+ N=386 (58.8%) | 2021 MRI+ N=333 (50.7%) | 2009 MRI+/2021 MRI– N=53 (8.1%) | ||||
| r-axSpA (n=195) | nr-axSpA (n=191) | r-axSpA (n=177) | nr-axSpA (n=156) | r-axSpA (n=18) | nr-axSpA (n=35) | |
| Age, years, mean (SD) | 32.7 (6.8) | 31.9 (7.0) | 32.7 (6.9) | 31.1 (6.5) | 32.4 (5.5) | 35.4 (8.0) |
| Male, n (%) | 154 (79.0) | 123 (64.4) | 138 (78.0) | 109 (69.9) | 16 (88.9) | 14 (40.0) |
| CRP, mg/L, mean (SD) | 17.3 (17.7) | 11.0 (18.5) | 17.1 (17.1) | 11.5 (19.0) | 19.6 (23.3) | 8.6 (15.9) |
| HLA-B27 positive, n (%) | 169 (86.7) | 148 (77.5) | 153 (86.4) | 127 (81.4) | 16 (88.9) | 21 (60.0) |
| Symptom duration, years | ||||||
| Mean (SD) | 3.5 (2.1) | 2.9 (1.6) | 3.6 (2.2) | 2.9 (1.6) | 3.2 (1.3) | 3.2 (1.8) |
| Median (range) | 3.9 (0.2–19.4) | 2.9 (0.2–8.4) | 4.0 (0.2–19.4) | 2.9 (0.2–7.9) | 3.2 (0.6–5.0) | 3.3 (0.3–8.4) |
| Disease duration, years | ||||||
| Mean (SD) | 2.2 (1.6) | 1.9 (1.6) | 2.2 (1.7) | 1.8 (1.5) | 2.5 (1.6) | 2.1 (1.6) |
| Median (range) | 1.9 (0.2–5.6) | 1.2 (0.2–5.0) | 1.8 (0.2–5.6) | 1.2 (0.2–5.0) | 2.8 (0.2–4.6) | 2.0 (0.2–5.0) |
| BASDAI, mean (SD) | 6.8 (1.4) | 6.6 (1.4) | 6.8 (1.4) | 6.5 (1.4) | 6.2 (1.7) | 6.9 (1.4) |
| ASDAS, mean (SD) | 4.0 (0.8) | 3.5 (0.8) | 4.0 (0.7) | 3.5 (0.8) | 3.8 (1.0) | 3.5 (0.7) |
| ASDAS disease state, n (%) | ||||||
| ID | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) |
| LDA | 2 (1.0) | 4 (2.1) | 1 (0.6) | 4 (2.6) | 1 (5.6) | 0 (0) |
| HDA | 52 (26.7) | 95 (49.7) | 45 (25.4) | 78 (50.0) | 7 (38.9) | 17 (48.6) |
| vHDA | 141 (72.3) | 92 (48.2) | 131 (74.0) | 74 (47.4) | 10 (55.6) | 18 (51.4) |
Patient demographics and baseline characteristics for patients categorised as MRI—according to the 2009 and preliminary 2021 MRI cut-offs for inflammatory lesions are given in online supplemental table 1.
ASDAS, Ankylosing Spondylitis Disease Activity Score; axSpA, axial spondyloarthritis; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; CRP, C reactive protein; CRP, C-reactive protein; HDA, high disease activity; HLA-B27, human leukocyte antigen B27; ID, inactive disease; LDA, low disease activity; MRI, magnetic resonance imaging; nr-axSpA, non-radiographic axSpA; r-axSpA, radiographic axSpA; SD, standard deviation; vHDA, very high disease activity.