Table 1.
Baseline characteristics of urban and rural dwellers
| Urban dwellers | Rural dwellers | Difference (rural vs urban) |
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| Demographic characteristics | n | Mean (SD) | n | Mean (SD) | Mean difference (95% CI) | |
| Age* | Years | 1810 | 47.4 (14.5) | 579 | 50.5 (13.9) | 3.1 (1.7 to 4.4) |
| Local area deprivation* | 1 (most) – 5 (least) | 1811 | 3.0 (1.4) | 579 | 3.8 (1.0) | 0.8 (0.7 to 0.9) |
| n | % | n | % | Mean % difference (95% CI) | ||
| Gender | Male | 1242 | 68.6 | 394 | 68.0 | −0.6 (−8.3 to 7.1) |
| Smoking status* | Never | 597 | 43.8 | 206 | 45.2 | 1.4 (−5.6 to 8.4) |
| Ex | 475 | 34.8 | 184 | 40.3 | 5.5 (−1.0 to 12.0) | |
| Current | 291 | 21.3 | 66 | 14.5 | −6.8 (−10.9 to −2.7) | |
| Alcohol | Never | 94 | 6.9 | 30 | 6.6 | −0.3 (−2.8 to 2.2) |
| Ex | 243 | 17.9 | 78 | 17.1 | −0.8 (−5.1 to 3.5) | |
| Current | 1021 | 75.2 | 348 | 76.3 | 1.1 (−8.1 to 10.3) | |
| Employed | Yes | 528 | 38.4 | 175 | 37.9 | −0.5 (−6.9 to 5.9) |
| Job type* | Mainly desk/sedentary | 465 | 56.4 | 127 | 45.8 | −10.6 (−20.0 to −1.2) |
| Mainly physical/labour-intense | 360 | 43.6 | 150 | 54.2 | 10.6 (0.9 to 20.3) | |
| Clinical characteristics | ||||||
| HLA-B27 status* | Tested | 1203 | 66.4 | 412 | 71.2 | 4.8 (−3.0 to 12.6) |
| NSAID | Prescribed (last 6 months) | 1340 | 74.6 | 431 | 75.0 | 0.4 (−7.7 to 8.5) |
| DMARD | Prescribed (last 6 months) | 170 | 13.4 | 63 | 15.7 | 2.3 (−1.9 to 6.5) |
| Images taken | X-ray | 1493 | 82.4 | 490 | 84.6 | 2.2 (−6.3 to 10.7) |
| MRI* | 1225 | 67.6 | 361 | 62.3 | −5.3 (−12.7 to 2.1) | |
| ESM (history) | Uveitis present | 433 | 24.1 | 128 | 22.3 | −1.8 (−6.2 to 2.6) |
| Psoriasis present | 203 | 11.3 | 59 | 10.3 | −1.0 (−3.9 to 1.9) | |
| IBD present | 190 | 10.6 | 54 | 9.4 | −1.2 (−4.0 to 1.6) | |
| Dactylitis present | 69 | 3.8 | 25 | 4.3 | 0.5 (−1.2 to 2.2) | |
| Enthesitis present | 174 | 9.9 | 65 | 11.3 | 1.4 (−1.36 to 4.4) | |
| PJD present | 320 | 17.8 | 116 | 20.2 | 2.4 (−1.7 to 6.5) | |
| Patient-reported characteristics | ||||||
| n | Mean (SD) | n | Mean (SD) | Mean difference (95% CI) | ||
| Referral delay† | Years | 1784 | 7.8 (9.8) | 571 | 8.6 (10.2) | 0.8 (−0.2 to 1.7) |
| Disease activity | BASDAI: 0 (best) – 10 (worst) | 1364 | 4.9 (2.6) | 454 | 4.7 (2.5) | −0.2 (−0.4 to 0.1) |
| Physical function | BASFI: 0 (best) – 10 (worst) | 1374 | 4.6 (2.9) | 461 | 4.7 (2.8) | 0.1 (−0.4 to 0.2) |
| Spinal mobility | BASMI: 0 (best) – 10 (worst) | 1288 | 3.9 (2.0) | 453 | 3.9 (1.9) | 0 (−02 to 0.3) |
| Global health | BASG: 0 (best) – 10 (worst) | 1364 | 5.2 (2.8) | 458 | 4.9 (2.7) | −0.3 (−0.5 to 0.1) |
| Spinal pain | VAS: 0 (best) – 10 (worst) | 1366 | 4.5 (3.0) | 457 | 4.4 (2.9) | −0.1 (−0.4 to 0.2) |
| SF-12 MCS* | Scored: 0 (worst) – 100 (best) | 1332 | 45.3 (11.6) | 455 | 47.6 (11.1) | 2.3 (1.1 to 3.5) |
| SF-12 PCS | Scored: 0 (worst) – 100 (best) | 1332 | 38.4 (11.9) | 455 | 38.1 (11.9) | −0.3 (−1.6 to 1.0) |
| Quality of life | ASQoL: 0 (best) – 18 (worst) | 1362 | 8.8 (5.8) | 458 | 8.3 (5.5) | −0.5 (−1.1 to 0.1) |
| Anxiety* | HADS: 0 (best) – 21 (worst) | 1362 | 7.9 (4.8) | 455 | 7.1 (4.6) | −0.8 (−1.3 to −0.3) |
| Depression* | HADS: 0 (best) – 21 (worst) | 1362 | 6.1 (4.2) | 455 | 5.5 (4.1) | −0.6 (−1.1 to −0.2) |
| Sleep disturbance | Jenkins Sleep Evaluation Questionnaire: 0 (best) – 20 (worst) | 1368 | 10.5 (6.2) | 461 | 10.0 (6.4) | −0.5 (−1.2 to 0.1) |
| Fatigue* | CFS: 0 (best) – 11 (worst) | 1379 | 4.3 (3.8) | 463 | 3.9 (3.7) | −0.4 (−0.8 to −0.04) |
| Work absenteeism | % | 760 | 6.8 (20.2) | 258 | 5.8 (17.6) | −1.0 (−3.7 to 1.8) |
| Work presenteeism | % | 758 | 31.2 (27.1) | 258 | 31.8 (25.8) | 0.6 (−3.2 to 4.4) |
| Overall work impairment | % | 737 | 32.3 (28.0) | 251 | 33.3 (27.2) | 1.0 (−3.0 to 5.0) |
| Activity impairment | % | 1350 | 44.4 (30.0) | 452 | 42.5 (28.5) | −1.9 (−5.1 to 1.2) |
*Indicates significant difference between urban and rural dwellers (p<0.05).
†Delay from symptom onset to first referral to specialist clinic.
ASQoL, Ankylosing Spondylitis Quality of Life Index; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; BASG, Bath Ankylosing Spondylitis Patient Global Score; BASMI, Bath Ankylosing Spondylitis Metrology Index; CFS, Chalder Fatigue Scale; DMARD, disease-modifying antirheumatic drugs; ESM, extraspinal manifestations; HADS, Hospital Anxiety and Depression Scale; IBD, inflammatory bowel disease; NSAID, non-steroidal anti-inflammatory drug; PJD, peripheral joint disease; SF-12 MCS, Short Form-12 Mental Component Score; SF-12 PCS, Short Form-12 Physical Component Score; VAS, Visual Analogue Scale.