Table 4.
Baseline characteristics of cases of congestive heart failure and matched controls*. Values are numbers (percentages) unless stated otherwise
| Characteristics | Cases (n=2623) | Controls (n=12 344) | Standardised difference† |
|---|---|---|---|
| Demographics | |||
| Mean (95% CI) age at index date | 82.0 (81.7 to 82.3) | 82.0 (81.9 to 82.2) | 0 |
| Male sex | 1196 (45.6) | 5636 (45.7) | 0 |
| Fifth of income: | |||
| Missing | 12 (0.5) | 42 (0.3) | 0.03 |
| 1 | 552 (21.0) | 2425 (19.6) | 0.04 |
| 2 | 569 (21.7) | 2566 (20.8) | 0.02 |
| 3 | 553 (21.1) | 2484 (20.1) | 0.02 |
| 4 | 479 (18.3) | 2446 (19.8) | 0.04 |
| 5 | 458 (17.5) | 2381 (19.3) | 0.05 |
| Rural residence | 419 (16.0) | 1812 (14.7) | 0.04 |
| Comorbidities | |||
| Mean (SD) No of unique drugs prescribed in previous year | 21.0 (8.7) | 12.8 (7.8) | 1.03 |
| Atrial fibrillation | 348 (13.3) | 1174 (9.5) | 0.12 |
| Coronary artery bypass grafting surgery | 121 (4.6) | 302 (2.4) | 0.13 |
| Cancer | 286 (10.9) | 690 (5.6) | 0.22 |
| Chronic renal insufficiency | 590 (22.5) | 569 (4.6) | 0.69 |
| Diabetes | 1413 (53.9) | 6561 (53.2) | 0.01 |
| Drugs used in previous year | |||
| Angiotensin converting enzyme inhibitors | 1547 (59.0) | 5346 (43.3) | 0.32 |
| Angiotensin receptor blockers | 824 (31.4) | 2957 (24.0) | 0.17 |
| Hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins) | 1682 (64.1) | 6489 (52.6) | 0.23 |
| Clopidogrel | 464 (17.7) | 922 (7.5) | 0.36 |
| Warfarin | 1053 (40.1) | 1737 (14.1) | 0.69 |
| Acetylsalicylic acid/dipyridamole | 58 (2.2) | 264 (2.1) | 0 |
| Hormone replacement therapy | 27 (1.0) | 83 (0.7) | 0.04 |
| Low molecular weight heparin | 57 (2.2) | 121 (1.0) | 0.11 |
| Diuretics | 2345 (89.4) | 6070 (49.2) | 0.85 |
| Diuretics, potassium sparing | 592 (22.6) | 918 (7.4) | 0.51 |
| Calcium channel blocker | 1412 (53.8) | 4748 (38.5) | 0.31 |
| History of outcome | |||
| Congestive heart failure | 355 (13.5) | 1041 (8.4) | 0.18 |
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.