Baseline characteristics of low-dose aspirin and paracetamol users*
| Characteristics | Before propensity score matching | After propensity score matching | ||||
| Low-dose aspirin (n=60 869) | Paracetamol (n=367 290) | Standardised difference† | Low-dose aspirin (n=49 679) | Paracetamol (n=49 679) | Standardised difference† | |
| Age, mean (SD), years | 69.1 (12.5) | 57.6 (12.8) | 0.912 | 68.0 (12.5) | 69.1 (12.7) | 0.09 |
| Female | 29 010 (47.7) | 211 841 (57.7) | 0.202 | 24 031 (48.4) | 23 991 (48.3) | 0.002 |
| Aspirin dose | ||||||
| ≤100 mg | 52 125 (85.6) | – | – | 42 756 (86.1) | – | – |
| 101 mg – 200 mg | 7396 (12.2) | – | – | 5909 (11.9) | – | – |
| 200 mg – 300 mg | 1348 (2.2) | – | – | 1014 (2.0) | – | – |
| Medical conditions | ||||||
| Hypertension | 12 679 (20.8) | 18 469 (5.0) | 0.485 | 8651 (17.4) | 8626 (17.4) | 0.001 |
| Congestive heart failure | 3676 (6.0) | 1568 (0.4) | 0.321 | 1734 (3.5) | 1289 (2.6) | 0.05 |
| Arrhythmia and conduction disorders | 8397 (13.8) | 3563 (1.0) | 0.506 | 3915 (7.9) | 2900 (5.8) | 0.08 |
| Arterial disease | 601 (1.0) | 578 (0.2) | 0.110 | 378 (0.8) | 321 (0.6) | 0.01 |
| Valve disorders | 436 (0.7) | 579 (0.2) | 0.085 | 266 (0.5) | 254 (0.5) | 0.003 |
| Cardiomyopathy | 329 (0.5) | 149 (0.0) | 0.093 | 165 (0.3) | 114 (0.2) | 0.02 |
| Diabetes mellitus | 9079 (14.9) | 12 148 (3.3) | 0.412 | 6079 (12.2) | 5975 (12.0) | 0.006 |
| Hyperlipidaemia | 2130 (3.5) | 2662 (0.7) | 0.194 | 1400 (2.8) | 1325 (2.7) | 0.009 |
| Thyroid disorders | 1189 (2.0) | 4644 (1.3) | 0.055 | 851 (1.7) | 837 (1.7) | 0.002 |
| Major bleeding | 408 (0.7) | 1269 (0.3) | 0.046 | 316 (0.6) | 343 (0.7) | 0.007 |
| COPD | 2868 (4.7) | 6214 (1.7) | 0.172 | 2062 (4.2) | 2109 (4.2) | 0.005 |
| Obesity | 214 (0.4) | 358 (0.1) | 0.054 | 139 (0.3) | 144 (0.3) | 0.002 |
| CKD | 1359 (2.2) | 1343 (0.4) | 0.165 | 801 (1.6) | 737 (1.5) | 0.01 |
| Chronic liver disease | 544 (0.9) | 1953 (0.5) | 0.043 | 437 (0.9) | 462 (0.9) | 0.005 |
| GERD | 150 (0.2) | 410 (0.1) | 0.032 | 105 (0.2) | 115 (0.2) | 0.004 |
| Irritable bowel syndrome | 45 (0.1) | 293 (0.1) | 0.002 | 37 (0.1) | 41 (0.1) | 0.003 |
| Peptic ulcer | 244 (0.4) | 952 (0.3) | 0.025 | 193 (0.4) | 186 (0.4) | 0.002 |
| Inflammatory bowel disease | 11 (0.0) | 106 (0.0) | 0.007 | 10 (0.0) | 8 (0.0) | 0.003 |
| Alcoholism | 1166 (1.9) | 3005 (0.8) | 0.095 | 826 (1.7) | 836 (1.7) | 0.002 |
| Schizophrenia | 1125 (1.8) | 5699 (1.6) | 0.023 | 900 (1.8) | 916 (1.8) | 0.002 |
| Bipolar disorder | 95 (0.2) | 706 (0.2) | 0.009 | 87 (0.2) | 98 (0.2) | 0.005 |
| Depression | 1158 (1.9) | 6291 (1.7) | 0.014 | 943 (1.9) | 942 (1.9) | <0.001 |
| Medications | ||||||
| Diuretics | 14 350 (23.6) | 28 961 (7.9) | 0.441 | 10 042 (20.2) | 10 136 (20.4) | 0.005 |
| ACE inhibitor or ARB | 16 819 (27.6) | 20 267 (5.5) | 0.623 | 11 195 (22.5) | 11 003 (22.1) | 0.009 |
| Other antihypertensives | 8785 (14.4) | 18 471 (5.0) | 0.321 | 6384 (12.9) | 6676 (13.4) | 0.02 |
| CCB | 22 514 (37.0) | 45 062 (12.3) | 0.599 | 16 622 (33.5) | 17 637 (35.5) | 0.04 |
| Antiarrhythmic | 1562 (2.6) | 1335 (0.4) | 0.184 | 760 (1.5) | 537 (1.1) | 0.04 |
| Beta-blockers | 21 756 (35.7) | 42 667 (11.6) | 0.592 | 15 777 (31.8) | 16 466 (33.1) | 0.03 |
| Peripheral vasodilators | 741 (1.2) | 598 (0.2) | 0.128 | 435 (0.9) | 373 (0.8) | 0.01 |
| Oral hypoglycaemic | 14 789 (24.3) | 25 443 (6.9) | 0.493 | 10 799 (21.7) | 11 260 (22.7) | 0.02 |
| Insulin | 3321 (5.5) | 2686 (0.7) | 0.275 | 1972 (4.0) | 1790 (3.6) | 0.02 |
| Lipid lowering drugs | 10 680 (17.5) | 10 362 (2.8) | 0.502 | 7019 (14.1) | 6835 (13.8) | 0.01 |
| PPI or H2-blockers | 21 143 (34.7) | 39 028 (10.6) | 0.601 | 14 323 (28.8) | 13 898 (28.0) | 0.02 |
| NSAID | 8324 (13.7) | 62 026 (16.9) | 0.089 | 7137 (14.4) | 7503 (15.1) | 0.02 |
| Oral bisphosphonates | 245 (0.4) | 455 (0.1) | 0.054 | 182 (0.4) | 186 (0.4) | 0.001 |
| Oral corticosteroids | 7561 (12.4) | 30 915 (8.4) | 0.131 | 5913 (11.9) | 6136 (12.4) | 0.01 |
| Anticoagulants | 2537 (4.2) | 1359 (0.4) | 0.257 | 1278 (2.6) | 962 (1.9) | 0.04 |
| Antiplatelet | 1408 (2.3) | 328 (0.1) | 0.205 | 532 (1.1) | 316 (0.6) | 0.05 |
| Antipsychotics | 2172 (3.6) | 7718 (2.1) | 0.088 | 1664 (3.3) | 1708 (3.4) | 0.005 |
| Antidepressants | 2583 (4.2) | 10 947 (3.0) | 0.068 | 2063 (4.2) | 2110 (4.2) | 0.005 |
*Values are expressed as frequency (%) unless otherwise specified.
†Standardised difference indicates difference in mean or proportion of covariates in the low-dose aspirin group versus the paracetamol group divided by the pooled SD.
ACE, angiotensin-converting enzyme; ARB, angiotensin II receptor blocker; CCB, calcium channel blocker; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; GERD, gastro-oesophageal reflux disease; H2-blockers, histamine-2 receptor blockers; NSAID, non-steroidal anti-inflammatory drug; PPI, proton pump inhibitors.