Table 3.
Baseline characteristics of cases of venous thromboembolism and matched controls*. Values are numbers (percentages) unless stated otherwise
| Characteristics | Cases (n=1059) | Controls (n=5259) | Standardised difference† |
|---|---|---|---|
| Demographics | |||
| Mean (95% CI) age at index date | 79.0 (78.5 to 79.4) | 79.0 (78.8 to 79.2) | 0 |
| Male sex | 402 (38.0) | 1987 (37.8) | 0 |
| Fifth of income: | |||
| Missing | ≤5 (0.4) | 23 (0.4) | 0 |
| 1 | 214 (20.2) | 991 (18.8) | 0.04 |
| 2 | 231 (21.8) | 1032 (19.6) | 0.05 |
| 3 | 213 (20.1) | 999 (19.0) | 0.03 |
| 4 | 203 (19.2) | 1122 (21.3) | 0.05 |
| 5 | 194 (18.3) | 1092 (20.8) | 0.06 |
| Rural residence | 173 (16.3) | 759 (14.4) | 0.05 |
| Comorbidities | |||
| Mean (SD) No of unique drugs prescribed in previous year | 15.0 (8.1) | 11.3 (7.2) | 0.49 |
| Atrial fibrillation | 272 (25.7) | 905 (17.2) | 0.22 |
| Coronary artery bypass grafting surgery | 20 (1.9) | 95 (1.8) | 0.01 |
| Cancer | 145 (13.7) | 278 (5.3) | 0.34 |
| Chronic renal insufficiency | 61 (5.8) | 135 (2.6) | 0.18 |
| Diabetes | 327 (30.9) | 1618 (30.8) | 0 |
| Drugs used in previous year | |||
| Angiotensin converting enzyme inhibitors | 408 (38.5) | 1992 (37.9) | 0.01 |
| Angiotensin receptor blockers | 248 (23.4) | 1178 (22.4) | 0.02 |
| Hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins) | 499 (47.1) | 2524 (48.0) | 0.02 |
| Clopidogrel | 82 (7.7) | 301 (5.7) | 0.08 |
| Warfarin | 305 (28.8) | 582 (11.1) | 0.52 |
| Acetylsalicylic acid/dipyridamole | 20 (1.9) | 94 (1.8) | 0.01 |
| Hormone replacement therapy | 14 (1.3) | 48 (0.9) | 0.04 |
| Low molecular weight heparin | 128 (12.1) | 51 (1.0) | 0.69 |
| Diuretics | 551 (52.0) | 2242 (42.6) | 0.19 |
| Diuretics, potassium sparing | 100 (9.4) | 325 (6.2) | 0.13 |
| Calcium channel blocker | 399 (37.7) | 1768 (33.6) | 0.09 |
| History of outcome | |||
| Venous thromboembolism | 46 (4.3) | 194 (3.7) | 0.03 |
All cells with values of 5 or less are reported as ≤5 for privacy reasons.
*Up to 5 controls were matched to each case on age (±1 year), sex, diabetes, and history of outcome.
†Difference between cases and controls divided by pooled standard deviation of two groups; standardised differences <0.1 indicate good balance between groups.