Baseline characteristics: demographic and clinical features of spondyloarthritis
| Characteristic | SpA | nr-axSpA | AS | M-W/FET p value | |
| Age (years), median (IQR) | 34.7 (29.3–43.5) | 36.9 (29.2–46.9) | 36.0 (29.3–44.1) | 0.551 | |
| Gender | Male number (%) | 131 (53.3) | 54 (38.6) | 77 (72.6) | <0.001 |
| BMI (kg/m2), median (IQR) | 24.3 (21.7–27.4) | 24.8 (21.6–28.2) | 24.2 (22.6–26.6) | 0.946 | |
| History of smoking | |||||
| Ever-smoker, number (%) | 107 (43.7) | 52 (37.1) | 55 (52.4) | 0.138 | |
| HLA-B27 positive, number (%) | 215 (87.4) | 117 (83.6) | 98 (92.5) | 0.051 | |
| Disease duration, years (IQR) | 7.8 (3.1–14.5) | 5.6 (2.6–12.2) | 10.2 (5.1–15.5) | 0.001 | |
| First symptom | 0.086 | ||||
| Back pain, number (%) | 195 (79.3) | 104 (74.3) | 91 (85.8) | ||
| Peripheral arthritis, number (%) | 27 (11.0) | 19 (13.6) | 8 (7.5) | ||
| Extra-articular manifestations, number (%) | 24 (9.8) | 17 (12.1) | 7 (6.6) | ||
| Family history | |||||
| First-degree relatives, number (%) | 86 (35.0) | 38 (27.1) | 24 (22.6) | 0.460 | |
| Second-degree relatives, number (%) | 28 (11.4) | 18 (12.9) | 10 (9.4) | 0.426 | |
| History of | |||||
| Peripheral arthritis, number (%) | 68 (27.6) | 50 (35.7) | 18 (17) | 0.001 | |
| Hip arthritis, number (%) | 32 (13.0) | 12 (8.6) | 20 (18.9) | 0.022 | |
| Uveitis, number (%) | 63 (25.6) | 39 (27.9) | 24 (22.6) | 0.379 | |
| IBD, number (%) | 13 (5.3) | 9 (6.4) | 4 (3.8) | ||
| Psoriasis, number (%) | 1 (0.4) | 0 (0) | 1 (0.9) | ||
| Other, number (%) | 3 (1.2) | 1 (0.7) | 2 (1.9) | ||
| Current symptoms | |||||
| MASES, median (IQR) | 0.0 (0.0–2.0) | 0.0 (0.0–2.0) | 0.0 (0.0–1.3) | 0.289 | |
| SJC, mean (±SD) | 0.4 (1.4) | 0.5 (1.5) | 0.3 (1.4) | 0.021 | |
| TJC, mean (±SD) | 0.4 (1.4) | 0.5 (1.4) | 0.3 (1.7) | 0.015 | |
| Current medication | |||||
| NSAIDs, number (%) | 126 (51.2) | 71 (50.7) | 55 (51.9) | 0.898 | |
| CsDMARDs, number (%) | 39 (15.9) | 26 (18.6) | 13 (12.3) | 0.218 | |
| Corticosteroids, number (%) | 5 (2) | 2 (1.4) | 3 (2.8) | ||
| BoDMARDs/bsDMARDs, number (%)* | 6 (2.4) | 2 (1.4) | 4 (3.8) | ||
*Adalimumab two patients; certolizumab one patient; golimumab two patients; infliximab one patient.
AS, ankylosing spondylitis; BMI, Body Mass Index; BoDMARDs, biological original disease modifying antirheumatic drugs; bsDMARDs, biosimilar disease modifying antirheumatic drugs; csDMARDs, conventional synthetic disease modifying antirheumatic drugs; IBD, inflammatory bowel disease; MASES, Maastricht Ankylosing Spondylitis Enthesitis Score; M-W/FETp, Mann-Whitney/Fisher exact test p value; nr-axSpA, non-radiographic axial spondyloarthritis; NSAIDs, non-steroidal anti-inflammatory drugs; SJC, swollen joint count; SpA, spondyloarthritis; TJC, tender joint count.