Baseline characteristics of patients with ankylosing spondylitis (AS) and controls
| Characteristic | Patients with AS | Controls | p Value | ||
|---|---|---|---|---|---|
| n=3809 | (%) | n=26 197 | (%) | ||
| Males | 2686 | (70.5) | 18 519 | (70.7) | – |
| Age at index date (years) | |||||
| 16–29 | 728 | (19.1) | 5085 | (19.4) | – |
| 30–39 | 1038 | (27.3) | 7172 | (27.4) | – |
| 40–49 | 817 | (21.4) | 5674 | (21.7) | – |
| 50–59 | 570 | (15.0) | 3870 | (14.8) | – |
| 60–69 | 376 | (9.9) | 2551 | (9.7) | – |
| 70–79 | 206 | (5.4) | 1399 | (5.3) | – |
| 80+ | 74 | (1.9) | 446 | (1.7) | – |
| BMI | |||||
| <20 | 204 | (5.4) | 1280 | (4.9) | 0.21 |
| 20–25 | 1046 | (27.5) | 6934 | (26.5) | 0.20 |
| 25–30 | 879 | (23.1) | 6066 | (23.2) | 0.91 |
| >30 | 447 | (11.7) | 3086 | (11.8) | 0.94 |
| Unknown | 1223 | (32.4) | 8831 | (33.7) | 0.10 |
| Smoking status | |||||
| Never | 1668 | (43.8) | 11 962 | (45.7) | 0.03 |
| Current | 1403 | (36.8) | 8256 | (31.5) | <0.01 |
| Ex | 569 | (14.9) | 3605 | (13.8) | 0.05 |
| Unknown | 169 | (4.4) | 2374 | (9.1) | <0.01 |
| Alcohol use | |||||
| Yes | 2612 | (68.6) | 17 468 | (66.7) | 0.02 |
| No | 596 | (15.6) | 3251 | (12.4) | <0.01 |
| Unknown | 601 | (15.8) | 5478 | (20.9) | <0.01 |
| Disease history | |||||
| Any cardiovascular disease | 216 | (5.7) | 1317 | (5.0) | 0.09 |
| IHD | 164 | (4.3) | 898 | (3.4) | <0.01 |
| AMI | 69 | (1.8) | 354 | (1.4) | 0.02 |
| Stroke | 44 | (1.2) | 317 | (1.2) | 0.77 |
| Heart failure | 24 | (0.6) | 108 | (0.4) | 0.06 |
| Peripheral vascular disease | 38 | (1.0) | 246 | (0.9) | 0.73 |
| Hypertension | 316 | (8.3) | 2007 | (7.7) | 0.17 |
| Acute renal failure | 3 | (0.1) | 16 | (0.1) | 0.69 |
| Chronic renal failure | 2 | (0.1) | 62 | (0.2) | 0.02 |
| Hypercholesterolaemia | 165 | (4.3) | 1127 | (4.3) | 0.93 |
| Diabetes mellitus | 150 | (3.9) | 795 | (3.0) | <0.01 |
| History of drug use 6 months before the index date | |||||
| Any antihypertensives | 509 | (13.4) | 2902 | (11.1) | <0.01 |
| β-blockers | 199 | (5.2) | 1276 | (4.9) | 0.35 |
| Loop diuretics | 92 | (2.4) | 380 | (1.5) | <0.01 |
| Thiazide diuretics | 173 | (4.5) | 967 | (3.7) | 0.01 |
| ACE-I or ANG-II-R | 248 | (6.5) | 1449 | (5.5) | 0.01 |
| Calcium channel antagonist | 177 | (4.7) | 985 | (3.8) | <0.01 |
| Antiplatelet agents | 206 | (5.4) | 1142 | (4.4) | <0.01 |
| Nitrates | 94 | (2.5) | 391 | (1.5) | <0.01 |
| Antidiabetics* | 107 | (2.8) | 586 | (2.2) | 0.03 |
| Statins | 233 | (6.1) | 1363 | (5.2) | 0.02 |
| Asthma medication† | 289 | (7.6) | 1661 | (6.3) | <0.01 |
| NSAIDs | 1731 | (45.4) | 2163 | (8.3) | <0.01 |
| COX-2 inhibitors | 225 | (5.9) | 114 | (0.4) | <0.01 |
| Naproxen only | 303 | (8.0) | 298 | (1.1) | <0.01 |
| Other traditional NSAIDs | 1582 | (41.5) | 2071 | (7.9) | <0.01 |
Bold typeface indicates statistical significance (p<0.05). A χ2 test was performed to compare patients with AS and controls.
*Antidiabetics, including insulin.
†Asthma medication, including bronchodilators, inhaled corticosteroids, leukotriene receptor antagonists, β-2 agonists and theophylline.
AMI, acute myocardial infarction; ANG-II-R, angiotensin II receptor antagonist; AS, ankylosing spondylitis; BMI, body mass index; COX-2 inhibitors, cyclo-oxygenase-2 inhibitors; IHD, ischaemic heart disease; NSAIDs, non-steroidal anti-inflammatory drugs.