Odds ratios (OR) of relevant items for a diagnosis of axial SpA: results of logistic regression analysis
| AS | Non-radiographic axial SpA | Axial SpA | |
|---|---|---|---|
| Age ≤35 years | 2.5 (p=0.03) | 2.8 (p=0.03) | 2.6 (95% CI 1.5 to 4.5) (p=0.0009) |
| Alternating buttock pain | 3.3 (p=0.005) | 2.0 (p=0.1) | 2.7 (95% CI 1.4 to 5.5) (p=0.003) |
| Improvement by NSAIDs within 48 h or no NSAID | 2.9 (p=0.01) | NS | 1.2 (95% CI 0.7 to 2.2) (p=0.004) |
| Waking up in the second half of the night | 3.0 (p=0.005) | NS | 1.9 (95% CI 1.1 to 3.2) (p=0.001) |
| Improvement by movement not by rest | 2.0 (p=0.1) | 1.9 (p=0.07) | 1.9 (95% CI 1.0 to 3.4) (p=0.03) |
| History of psoriasis | NS | 3.6 (p=0.02) | 2.1 (95% CI 0.7 to 6.4) (p=0.2) |
| History of enthesitis | NS | 2.7 (p=0.03) | 2.3 (95% CI 1.0 to 5.1) (p=0.06) |
| History of anterior uveitis | 7.2 (p=0.07) | NS | 3.6 (95% CI 0.5 to 25.3) (p=0.2) |
| History of arthritis | 3.4 (p=0.079 | 2.5 (p=0.1) | 2.6 (95% CI 0.9 to 7.1) (p=0.06) |
| Family history of SpA | NS | 2.5 (p=0.1) | 2.3 (95% CI 0.8 to 6.6) (p=0.1) |
AS, ankylosing spondylitis; NS, not significant; NSAID, non-steroidal anti-inflammatory agent; SpA, spondyloarthritis.