Baseline characteristics of the included patients
| Parameter | Non-radiographic axial spondyloarthritis (n=95) | AS (n=115) | All patients (n=210) |
|---|---|---|---|
| Age (years) | 38.7±9.9 | 36.8±11.0 | 37.1±10.6 |
| Duration of symptoms (years) | 3.2±2.2 | 5.2±2.8 | 4.2±2.7 |
| Male gender (%) | 33.7 | 65.2 | 51.0 |
| HLA-B27 (+) (%) | 72.6 | 84.3 | 79.0 |
| Peripheral arthritis (%) | 16.8 | 13.0 | 14.8 |
| Enthesitis* (%) | 24.2 | 20.0 | 21.9 |
| Uveitis ever (%) | 15.8 | 23.5 | 20.0 |
| Psoriasis ever (%) | 11.6 | 14.8 | 13.3 |
| IBD ever (%) | 1.1 | 2.6 | 1.9 |
| Family history of AS (%) | 16.8 | 16.5 | 16.7 |
| BASDAI (points NRS) | 4.2±2.0 | 3.8±2.2 | 3.9±2.2 |
| BASFI (points NRS) | 2.8±2.2 | 3.0±2.4 | 2.9±2.3 |
| Treatment with NSAID (%) | 67.4 | 66.1 | 66.7 |
| Treatment with DMARD (%) | 27.4 | 30.4 | 29.0 |
| Treatment with systemic steroids (%) | 6.3 | 5.2 | 5.7 |
| Treatment with a TNFα blocker (%) | 1.1 | 3.5 | 2.4 |
↵* Berlin score with 12 enthesitis points of the lower limbs assessed.12
AS, ankylosing spondylitis; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; DMARD, disease-modifying antirheumatic drug; HLA-B27, human leucocyte antigen B27; IBD, inflammatory bowel disease; NRS, numeric rating scale; NSAID, non-steroidal anti-inflammatory drug; TNFα, tumour necrosis factor alpha.