Table 1.
Characteristics of all patients classified as having nonradiographic axial spondyloarthritis at inclusion in SCQM
| Parameter | A. All nr-axSpA patients | B. All nr-axSpA patients excluding patients with co-morbid FM | ||||||
|---|---|---|---|---|---|---|---|---|
| N, 495 | Men, N = 231 | Women, N = 264 | p | N, 470 | Men, N = 227 | Women, N = 243 | p | |
| Age, years | 495 | 36.6 (10.9) | 38.2 (10.7) | 0.09 | 470 | 36.4 (10.9) | 38.1 (10.7) | 0.09 |
| Age at symptom onset, years | 481 | 28.3 (8.4) | 28.7 (9.1) | 0.65 | 456 | 28.2 (8.4) | 28.6 (9.0) | 0.65 |
| Symptom duration, years | 481 | 8.3 (9.2) | 9.6 (9.8) | 0.10 | 456 | 8.2 (9.2) | 9.5 (9.8) | 0.12 |
| Diagnostic delay, years | 480 | 4.7 (7.6) | 6.0 (7.8) | 0.005 | 455 | 4.7 (7.5) | 6.0 (7.8) | 0.01 |
| HLA-B27 positive, % | 453 | 76.5 | 67.0 | 0.03 | 430 | 77.0 | 68.2 | 0.05 |
| Positive family history for spondyloarthritis, % | 417 | 32.0 | 40.5 | 0.08 | 393 | 32.1 | 42.0 | 0.05 |
| Prior sacroiliitis on MRI, % | 477 | 52.9 | 58.7 | 0.23 | 453 | 53.9 | 58.5 | 0.34 |
| BASDAI | 430 | 4.6 (2.2) | 5.3 (2.1) | 0.003 | 412 | 4.6 (2.2) | 5.1 (2.1) | 0.02 |
| • BASDAI 1 (fatigue) | 436 | 4.7 (2.8) | 6.0 (2.4) | < 0.001 | 418 | 4.7 (2.8) | 5.9 (2.4) | < 0.001 |
| • BASDAI 2 (back pain) | 436 | 5.9 (2.7) | 6.5 (2.5) | 0.03 | 418 | 5.9 (2.7) | 6.3 (2.5) | 0.10 |
| • BASDAI 3 (joint pain/swelling) | 435 | 3.6 (3.1) | 4.2 (3.1) | 0.04 | 417 | 3.6 (3.1) | 4.1 (3.1) | 0.07 |
| • BASDAI 4 (enthesitis) | 433 | 4.2 (3.3) | 5.0 (3.1) | 0.02 | 415 | 4.2 (3.3) | 4.8 (3.0) | 0.04 |
| • BASDAI 5 (intensity of morning stiffness) | 434 | 5.2 (3.0) | 5.4 (3.1) | 0.65 | 416 | 5.3 (3.0) | 5.2 (3.1) | 0.96 |
| • BASDAI 6 (duration of morning stiffness) | 433 | 4.0 (2.9) | 4.1 (2.9) | 0.68 | 415 | 4.0 (2.9) | 4.0 (2.9) | 0.99 |
| Physician Global Assessment | 481 | 3.7 (2.2) | 3.8 (2.0) | 0.49 | 412 | 3.7 (2.2) | 3.7 (2.0) | 0.86 |
| Patient Global Assessment | 430 | 5.3 (2.9) | 5.6 (2.8) | 0.27 | 412 | 5.3 (2.9) | 5.5 (2.8) | 0.54 |
| ASDAS | 402 | 2.9 (1.0) | 2.9 (0.9) | 0.23 | 386 | 2.9 (1.0) | 2.9 (0.9) | 0.49 |
| CRP (mg/l), median (IQR) | 463 | 4.0 (1.0; 8.0) | 4.0 (2.0; 8.0) | 0.86 | 441 | 4.0 (1.1; 8.0) | 4.0 (2.0; 8.0) | 0.96 |
| Elevated CRP, % | 459 | 26.5 | 26.6 | 1.00 | 437 | 26.5 | 26.1 | 1.00 |
| BASFI | 435 | 2.8 (2.4) | 3.1 (2.5) | 0.16 | 416 | 2.8 (2.4) | 2.9 (2.4) | 0.54 |
| BASMI | 473 | 1.3 (1.4) | 1.3 (1.3) | 0.98 | 449 | 1.4 (1.4) | 1.3 (1.2) | 0.72 |
| EQ-5D | 431 | 61.4 (22.5) | 59.7 (20.1) | 0.34 | 412 | 61.3 (22.6) | 61.2 (19.4) | 0.78 |
| IBP according to ASAS, % | 462 | 80.5 | 77.3 | 0.43 | 437 | 80.6 | 77.0 | 0.41 |
| Spinal MRI inflammation, % | 476 | 26.9 | 24.9 | 0.67 | 452 | 26.9 | 23.6 | 0.45 |
| Spinal radiographic changes, % | 476 | 6.3 | 3.6 | 0.20 | 452 | 5.9 | 3.0 | 0.17 |
| Current peripheral arthritis,% | 489 | 35.8 | 39.2 | 0.46 | 464 | 36.0 | 38.9 | 0.57 |
| Number of swollen joints | 481 | 0.7 (1.9) | 0.9 (2.3) | 0.38 | 457 | 0.7 (1.9) | 0.7 (1.8) | 0.54 |
| Current enthesitis, % | 483 | 64.0 | 79.6 | < 0.001 | 459 | 63.8 | 78.3 | < 0.001 |
| Modified MASES | 481 | 1.9 (2.5) | 3.2 (3.4) | < 0.001 | 457 | 1.8 (2.5) | 2.9 (3.1) | < 0.001 |
| Co-morbid fibromyalgia, % | 307 | 2.7 | 13.1 | < 0.001 | – | – | – | – |
| Dactylitis ever, % | 492 | 10.9 | 11.4 | 0.89 | 468 | 10.6 | 12.0 | 0.66 |
| Uveitis ever, % | 434 | 18.1 | 13.1 | 0.18 | 410 | 18.4 | 12.9 | 0.14 |
| Psoriasis ever, % | 373 | 9.1 | 9.1 | 1.00 | 351 | 9.3 | 8.4 | 0.85 |
| Inflammatory bowel disease ever, % | 427 | 6.0 | 7.9 | 0.46 | 403 | 5.6 | 8.2 | 0.33 |
| Taking NSAIDs, % | 471 | 87.3 | 90.4 | 0.31 | 447 | 87.6 | 89.6 | 0.55 |
| Taking methotrexate, % | 495 | 5.2 | 10.2 | 0.04 | 470 | 5.3 | 9.9 | 0.08 |
| Taking sulfasalazine, % | 495 | 4.8 | 6.1 | 0.56 | 470 | 4.8 | 6.2 | 0.55 |
| Taking TNFi, % | 495 | 14.7 | 15.5 | 0.90 | 470 | 14.5 | 15.2 | 0.90 |
| Ever TNFi, % | 495 | 68.0 | 72.0 | 0.78 | 470 | 67.4 | 70.8 | 0.80 |
| Current smoking, % | 432 | 32.0 | 30.2 | 0.75 | 413 | 32.0 | 28.3 | 0.45 |
| Body mass index | 483 | 25.7 (3.9) | 24.3 (4.5) | < 0.001 | 458 | 25.6 (3.9) | 24.1 (4.2) | < 0.001 |
| Education, % | 462 | 0.46 | 440 | 0.52 | ||||
| • Compulsory | 15.8 | 19.8 | 15.2 | 18.3 | ||||
| • Vocational | 56.7 | 51.8 | 57.4 | 52.4 | ||||
| • University | 27.4 | 28.3 | 27.5 | 29.3 | ||||
| Absenteeism within last year, % | 389 | 53.9 | 44.0 | 0.12 | 372 | 53.9 | 43.2 | 0.10 |
All patients with nr-axSpA are presented in A, while patients with co-morbid fibromyalgia are excluded in B. Except where indicated otherwise, values are the mean (SD). Data in bold are statistically significant. ASAS Assessment of SpondyloArthritis international Society, ASDAS Ankylosing Spondylitis Disease Activity Score, BASDAI Bath Ankylosing Spondylitis Disease Activity Index, BASFI Bath Ankylosing Spondylitis Functional Index, BASMI Bath Ankylosing Spondylitis Metrology Index, CRP C-reactive protein, EQ-5D EuroQol 5-domains, FM fibromyalgia, HLA-B27 human leucocyte antigen B27, IBP inflammatory back pain, MASES Maastricht Ankylosing Spondylitis Enthesitis Score, modification refers to the inclusion of the plantar fascia in the count, MRI magnetic resonance imaging, nr-axSpA nonradiographic axial spondyloarthritis, NSAIDs nonsteroidal anti-inflammatory drugs, TNFi tumor necrosis factor inhibitor