Table 1.
Patient and disease characteristics of the cohort and for each smoking category
| All | Non-smokers | Ex-smokers | Current smokers | P value | |
|---|---|---|---|---|---|
| Number of patients | 238 | 126 (52.9%) | 34 (14.3%) | 78 (32.8%) | |
| Age | 46.4 (13.8) | 46.1 (14.2) | 51.7 (12.1) | 44.6 (13.2) | 0.046 |
| Male gender | 180 (75.6%) | 87 (69.1%) | 31 (91.2%) | 62 (79.5%) | 0.018 |
| BMIa | 27.6 [25.1, 31.0] | 27.4 [25.2, 30.5] | 29.0 [25.8, 32.6] | 27.6 [24.7, 31.0] | 0.443 |
| AS diagnosis | 197 (82.8%) | 99 (78.6%) | 27 (79.4%) | 71 (91.0%) | 0.062 |
| HLA-B27 statusa | 89 (61.0%) | 49 (59.8%) | 14 (70.0%) | 26 (59.1%) | 0.670 |
| Symptom duration (years) | 16.5 [8.4, 28.4] | 15.0 [6.4, 30.0] | 23.1 [12.6, 33.1] | 16.3 [8.8. 26.7] | 0.033 |
| Diagnosis duration (years) | 5.0 [0.8, 14.8] | 4.7 [0.8, 15.2] | 4.0 [1.2, 14.8] | 0.9 [5.4, 14.4] | 0.802 |
| Pack-years | 0 [0, 15] | 0 | 20 [10, 30] | 15 [9, 30] | 0.151b |
| BASDAI | 5.7 [3.3, 7.6] | 5.2 [3.0, 7.5] | 6.0 [4.1, 8.2] | 6.5 [3.6, 7.6] | 0.132 |
| Spinal pain | 6.0 [3.0, 8.0] | 5.0 [2.0, 8.0] | 7.0 [3.0, 8.0] | 7.0 [3.0, 8.0] | 0.254 |
| ASDASa | 2.70 (1.14) | 2.39 (1.16) | 3.28 (1.08) | 2.96 (0.98) | 0.001 |
| BASFI | 5.7 [2.9, 7.6] | 5.0 [2.3, 7.4] | 6.9 [3.1, 8.1] | 5.9 [3.2, 7.7] | 0.116 |
| CRP (mg/l)a | 3 [1, 9] | 3 [1, 8] | 5 [2, 11] | 5 [1, 11] | 0.131 |
| ESR (mm/hr) a | 8 [5, 21] | 8 [5, 19] | 10 [6, 26] | 10[5, 26] | 0.123 |
| Peripheral joint involvement | 55 (23.6%) | 35 (28.0%) | 8 (23.5%) | 12 (16.2%) | 0.167 |
| Psoriasis | 39 (16.4%) | 21 (16.70%) | 6 (17.7%) | 12 (15.4%) | 0.949 |
| Uveitis | 64 (26.9%) | 38 (30.2%) | 12 (35.3%) | 14 (18.0%) | 0.079 |
| IBD | 22 (9.2%) | 14 (11.1%) | 3 (8.8%) | 5 (6.4%) | 0.576 |
| TNFi | 79 (33.2%) | 39 (31.0%) | 12 (35.3%) | 28 (35.9%) | 0.737 |
| NSAID | 163 (68.5%) | 87 (69.1%) | 20 (58.8%) | 56 (71.8%) | 0.390 |
Data are presented in n (%), mean (SD), median [IQR] and comparison used Chi-squared/Fisher’s exact, ANOVA and Kruskal–Wallis tests, respectively
axSpA axial spondyloarthritis, ASDAS Ankylosing Spondylitis Disease Activity Score, BMI body mass index, IBD inflammatory bowel disease, TNFi TNF inhibition therapy, NSAID non-steroidal anti-inflammatory drugs
a BMI complete data in 190; HLAB27 status known in 146; ASDAS in 188; CRP in 231; ESR in 230
b Mann–Whitney U test