Table 2.
Numbers, proportions and odds ratios (95% CI) for features in cases of ankylosing spondylitis compared with population controls
| Occurrence of features in 3 years before index date | Occurrence of features at any time before index date | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cases (N = 74) | Controls (N = 296) | Cases (N = 74) | Controls (N = 296) | |||||||||
| Specific features | N | % | N | % | OR | (95% CI) | N | % | N | % | OR | (95% CI) |
| Axial pain | 39 | 52.7 | 31 | 10.5 | 9.8 | (5.1, 18.9) | 49 | 66.2 | 70 | 23.7 | 7.5 | (4.0, 14.2) |
| Other spine diagnosis | 16 | 21.6 | 17 | 5.7 | 5.1 | (2.3, 11.3) | 22 | 29.7 | 33 | 11.2 | 3.7 | (1.9, 7.3) |
| Sciatica | 5 | 6.8 | 8 | 2.7 | 2.8 | (0.8, 9.3) | 9 | 12.2 | 18 | 6.1 | 2.3 | (0.9, 5.8) |
| Large joint symptom | 14 | 18.9 | 25 | 8.5 | 2.7 | (1.3, 5.8) | 22 | 29.7 | 47 | 15.9 | 2.4 | (1.3, 4.4) |
| Other joint symptom | 5 | 6.8 | 4 | 1.4 | 6.0 | (1.4, 25.5) | 7 | 9.5 | 10 | 3.4 | 3.4 | (1.2, 9.8) |
| Tendon disorders | 9 | 12.2 | 12 | 4.1 | 3.4 | (1.3, 8.7) | 16 | 21.6 | 21 | 7.1 | 3.6 | (1.7, 7.3) |
| Iritis | 8 | 10.8 | 1 | 0.3 | 32.0 | (4.0, 255.9) | 12 | 16.2 | 3 | 1.0 | 16.0 | (4.5, 56.7) |
| Urethral symptoms | 2 | 2.7 | 1 | 0.3 | – | – | 3 | 4.1 | 8 | 2.7 | 1.5 | (0.4, 6.0) |
| Fatigue | 10 | 13.5 | 24 | 8.1 | 1.9 | (0.8, 4.2) | 12 | 16.2 | 39 | 13.2 | 1.3 | (0.6, 2.8) |
| Inflamm. Bowel disease | 7 | 9.5 | 4 | 1.4 | 7.0 | (2.1, 23.9) | 12 | 16.2 | 13 | 4.4 | 4.9 | (2.0, 12.3) |
| Other Inflamm. arthritis | 3 | 4.1 | 2 | 0.7 | – | – | 5 | 6.8 | 4 | 1.4 | – | – |
| X-ray spine | 6 | 8.1 | 0 | 0.0 | – | – | 7 | 9.5 | 2 | 0.7 | – | – |
| X-ray pelvis | 2 | 2.7 | 0 | 0.0 | – | – | 2 | 2.7 | 0 | 0.0 | – | – |
| Full Blood Count | 12 | 16.2 | 19 | 6.4 | 5.5 | (1.8, 16.4) | 15 | 20.3 | 23 | 7.8 | 9.2 | (2.5, 33.4) |
| ESR | 6 | 8.1 | 5 | 1.7 | 14.9 | (1.7, 127.8) | 7 | 9.5 | 6 | 2.0 | 9.7 | (2.0, 47.9) |
| MRI scan | 0 | 0.0 | 2 | 0.7 | – | – | 0 | 0.0 | 3 | 1.0 | – | – |
| NSAIDs | 52 | 70.3 | 60 | 20.3 | 12.9 | (6.3, 26.8) | 57 | 77.0 | 93 | 31.4 | 13.3 | (5.9, 29.9) |
| Analgesics | 37 | 50.0 | 43 | 14.5 | 6.0 | (3.3, 10.8) | 41 | 55.4 | 73 | 24.7 | 4.4 | (2.4, 7.8) |
| Opioids | 8 | 10.8 | 5 | 1.7 | 7.5 | (2.2, 25.0) | 10 | 13.5 | 8 | 2.7 | 7.9 | (2.4, 25.7) |
| Tricyclic antidepressants | 10 | 13.5 | 15 | 5.1 | 2.9 | (1.3, 6.8) | 12 | 16.2 | 18 | 6.1 | 3.2 | (1.4, 7.3) |
| SSRI antidepressants | 5 | 6.76 | 33 | 11.2 | 0.56 | (0.2, 1.5) | 12 | 16.22 | 13 | 4.39 | 4.91 | (2.0, 12.3) |
Features: Large Joint symptom codes relating to large limb joints (shoulder-wrist, hip-ankle); Other joint symptoms codes relating to joints distal to wrist/ ankle; ESR Erythrocyte sedimentation rate, MRI Magentic resonance imaging, NSAID Non-steroidal anti-inflammatory drugsm, Analgesics paracetamol, codeine; Opioids opioid drugs of the potency of tramadol or higher, SSRI Selective Serotonin Reuptake Inhibitor & related antidepressants; Index date: date of diagnosis for cases, date of diagnosis of matched case for controls