Table 1.
Demographics of patients in this study
| Demographics | axSpA (n = 366) | Not-axSpA (n = 622) | All (N = 988) |
|---|---|---|---|
| Age at diagnosis, years, mean (range) | 35.8 (17–59) | 52 (16–89) | 46 (16–89) |
| Male, n (%) | 259 (71.0) | 201 (32.3) | 460 (46.6) |
| Ethnic background, n (%) | |||
| White (including Eastern Europe) | 334 (91) | 505 (81) | 839 (85) |
| Asian (including South and East Asia) | 20 (5) | 45 (7) | 65 (7) |
| Hispanic | 4 (1) | 37 (6) | 41 (4) |
| African | 2 (1) | 25 (4) | 27 (3) |
| Other | 6 (2) | 10 (2) | 16 (2) |
| Referral source, n (%) | |||
| GP | 261 (71.3) | 473 (76) | 734 (74) |
| Community physiotherapists | 35 (9.5) | 31 (5) | 66 (7) |
| Specialist physiotherapist | 12 (3.3) | 12 (2) | 24 (2) |
| Orthopaedics | 29 (7.9) | 75 (12) | 104 (11) |
| Dermatology | 9 (2.5) | 19 (3) | 28 (3) |
| Gastroenterology | 10 (2.7) | 6 (1) | 16 (2) |
| Ophthalmology | 10 (2.7) | 6 (1) | 16 (2) |
| Classification of axSpA, n (%) | |||
| Radiographic axSpA | 284 (78) | – | 284 (29) |
| Non-radiographic axSpA | 82 (22) | – | 82 (8) |
| HLA-B27 positive, n (%) | 328 (90) | 93 (15) | 421 (43) |
| CRP, mg/l, mean (s.d.) | 5.8 (3.5) | 5.4 (4.6) | 5.6 (4.2) |
| X-ray SI joint positive for AS, n ( %) | 284 (78) | – | 284 (29) |
| MRI spine positive for axSpA, n (%) | 342/351 (97) | – | 342/792 (43) |
| MRI SI joint positive for axSpA, n (%) | 190/351 (54) | – | 190/792 (24) |
| ASAS classification of axSpA, n (%) | 331 (90) | – | 331 (34) |
| Extra-articular manifestations, n (%) | 120 (33) | 62 (10) | 182 (18) |
| Psoriasis, n (%) | 50 (14) | 19 (3) | 69 (7) |
| Uveitis, n (%) | 55 (15) | 31 (5) | 86 (9) |
| Inflammatory bowel disease, n (%) | 33 (9) | 6 (1) | 39 (4) |
| Ulcerative colitis, n (%) | 13 (4) | 4 (1) | 17 (2) |
| Crohn’s disease, n (%) | 20 (5) | 2 (0.5) | 22 (2) |
| Contact with other HCPs before diagnosis, n (%) | |||
| Physiotherapist | 255 (69) | 267 (43) | 522 (53) |
| Chiropractor/osteopath | 71 (19) | 236 (38) | 307 (31) |
| Dermatologist | 66 (18) | 37 (6) | 103 (10) |
| Orthopaedic | 84 (23) | 93 (15) | 177 (18) |
| Ophthalmologist | 55 (15) | 56 (9) | 111 (11) |
| Gastroenterologist | 45 (12) | 50 (8) | 95 (10) |
| Diagnosis of not-axSpA patients, n (%) | |||
| Mechanical back pain | – | 404 (65) | 404 (65) |
| SAPHO syndrome | – | 22 (4) | 22 (4) |
| Osteitis condensans ilii | – | 32 (5) | 32 (5) |
| Fibromyalgia | – | 86 (14) | 86 (14) |
| Polymyalgia rheumatica | – | 48 (8) | 48 (8) |
| Diffuse idiopathic skeletal hyperostosis | – | 30 (5) | 30 (5) |
SAPHO: synovitis, acne, pustulosis, hyperostosis, osteitis.