Table 1. Baseline characteristics of patients with and without ankylosing spondylitis.
| Demographic data | Patients with AS n = 2,058 |
Patients without AS n = 8,232 |
P value | ||
|---|---|---|---|---|---|
| n | % | n | % | ||
| Age (years)a | 38.01 (28.29–50.11) | 38.01 (28.30–50.11) | |||
| ≥ 65 | 227 | 11.0 | 908 | 11.0 | 0.998 |
| < 65 | 1,831 | 90.0 | 7,324 | 90.0 | |
| Sex | |||||
| Male | 1,314 | 63.8 | 5,256 | 63.8 | 0.999 |
| Female | 744 | 36.2 | 2,976 | 36.2 | |
| Comorbidities | |||||
| Depressive disorder | 44 | 2.1 | 66 | 0.8 | < 0.001 |
| Hypertension | 428 | 20.8 | 1,300 | 15.8 | < 0.001 |
| Diabetes mellitus | 234 | 11.4 | 709 | 8.6 | < 0.001 |
| Dyslipidemia | 333 | 16.2 | 907 | 11.0 | < 0.001 |
| Cerebrovascular disease | 277 | 13.5 | 672 | 8.2 | < 0.001 |
| COPD | 227 | 11.0 | 632 | 7.7 | < 0.001 |
| Nephropathy | 241 | 11.7 | 538 | 6.5 | < 0.001 |
| Autoimmune disease | 76 | 3.7 | 163 | 2.0 | < 0.001 |
| Obesity | 14 | 0.7 | 30 | 0.4 | 0.043 |
| Congestive heart failure | 44 | 2.1 | 102 | 1.2 | 0.003 |
| Hepatitis B | 80 | 3.9 | 158 | 1.9 | < 0.001 |
| Hepatitis C | 17 | 0.8 | 34 | 0.4 | 0.022 |
| Degree of urbanization | 0.541 | ||||
| Urban | 1,253 | 60.9 | 5,096 | 61.9 | |
| Suburban | 665 | 32.3 | 2,623 | 31.9 | |
| Rural | 140 | 6.8 | 513 | 6.2 | |
| Income group | < 0.001 | ||||
| High income | 340 | 16.5 | 1,077 | 13.1 | |
| Medium income | 416 | 20.2 | 1,687 | 20.5 | |
| Low income | 938 | 45.6 | 3,854 | 46.8 | |
| No income | 364 | 17.7 | 1,614 | 19.6 | |
| Follow-up yearsa | 10.87 (9.48–12.42) | 11.03 (9.65–12.48) | < 0.001 | ||
aMedian (interquartile range); COPD indicates chronic obstructive pulmonary disease