Table 3.
Numbers, proportions and odds ratios (95% CI) for features in cases of ankylosing spondylitis compared with symptomatic controls
| Occurrence of features in 3 years before index date | Occurrence of features at any time before index date | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cases (N = 74) | Controls (N = 169) | Cases (N = 74) | Controls (N = 169) | |||||||||
| Specific features | N | % | N | % | OR | (95% CI) | N | % | N | % | OR | (95% CI) |
| Axial pain | 39 | 52.7 | 93 | 55.0 | 1.0 | (0.6, 1.8) | 49 | 66.2 | 146 | 86.4 | 0.3 | (0.2, 0.6) |
| Other spine diagnosis | 16 | 21.6 | 25 | 14.8 | 1.8 | (0.8, 3.9) | 22 | 29.7 | 40 | 23.7 | 1.4 | (0.7, 2.7) |
| Sciatica | 5 | 6.8 | 19 | 11.2 | 0.6 | (0.2, 1.7) | 9 | 12.2 | 31 | 18.3 | 0.7 | (0.3, 1.4) |
| Large joint symptom | 14 | 18.9 | 14 | 8.3 | 2.1 | (0.9, 4.8) | 22 | 29.7 | 34 | 20.1 | 1.5 | (0.8, 2.9) |
| Other joint symptom | 5 | 6.8 | 4 | 2.4 | 2.7 | (0.6, 12.5) | 7 | 9.5 | 6 | 3.6 | 2.8 | (0.8, 10.3) |
| Tendon disorders | 9 | 12.2 | 10 | 5.9 | 2.1 | (0.8, 5.5) | 16 | 21.6 | 21 | 12.4 | 1.7 | (0.8, 3.6) |
| Iritis | 8 | 10.8 | 0 | 0.0 | – | – | 12 | 16.2 | 0 | 0.0 | – | – |
| Urethral symptoms | 2 | 2.7 | 1 | 0.6 | – | – | 3 | 4.1 | 4 | 2.4 | 1.5 | (0.3, 6.8) |
| Fatigue | 10 | 13.5 | 14 | 8.3 | 2.1 | (0.8, 5.7) | 12 | 16.2 | 22 | 13.0 | 1.3 | (0.5, 3.1) |
| Inflamm. Bowel disease | 7 | 9.5 | 2 | 1.2 | 12.0 | (1.5, 99.4) | 12 | 16.2 | 9 | 5.3 | 3.2 | (1.3, 7.8) |
| Other Inflamm. arthritis | 3 | 4.1 | 2 | 1.2 | – | – | 5 | 6.8 | 4 | 2.4 | 2.5 | (0.7, 9.5) |
| X-ray spine | 6 | 8.1 | 2 | 1.2 | 12.6 | (1.5, 106.7) | 7 | 9.5 | 3 | 1.8 | 13.7 | (1.6, 113.6) |
| X-ray pelvis | 2 | 2.7 | 0 | 0.0 | – | – | 2 | 2.7 | 1 | 0.6 | – | – |
| – | – | 16.2 | 18 | 10.7 | 3.2 | (1.0, 10.8) | 15 | 20.3 | 23 | 13.6 | 4.6 | (1.2, 17.5) |
| ESR | 6 | 8.1 | 1 | 0.6 | 14.3 | (1.7, 120.8) | 7 | 9.5 | 2 | 1.2 | 14.5 | (1.8, 120.7) |
| MRI scan | NA | NA | NA | NA | – | – | 0 | 0.0 | 2 | 1.2 | – | – |
| NSAIDs | 52 | 70.3 | 70 | 41.4 | 3.6 | (1.8, 7.1) | 57 | 77.0 | 94 | 55.6 | 3.1 | (1.4, 6.6) |
| Analgesics | 37 | 50.0 | 53 | 31.4 | 2.0 | (1.1, 3.6) | 41 | 55.4 | 77 | 45.6 | 1.4 | (0.8, 2.5) |
| Opioids | 8 | 10.8 | 10 | 5.9 | 1.8 | (0.7, 4.7) | 10 | 13.5 | 13 | 7.7 | 1.8 | (0.8, 4.2) |
| Tricyclic antidepressants | 10 | 13.5 | 14 | 8.3 | 1.6 | (0.7, 3.8) | 12 | 16.2 | 20 | 11.8 | 1.3 | (0.6, 3.0) |
| SSRI antidepressants | 5 | 6.76 | 24 | 14.2 | 0.37 | (0.1, 1.1) | 9 | 12.16 | 33 | 19.5 | 0.51 | (0.2, 1.2) |
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 drugs, 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