Table 1.
Baseline characteristics of the study population
| Women, age (years) |
Men, age (years) |
|||
|---|---|---|---|---|
| Characteristics | 50–70 (n = 63475) | 70–90 (n = 35650) | 50–70 (n = 56589) | 70–90 (n = 17815) |
| Age—years, median (IQR) | 59 (55–64) | 78 (74–82) | 59 (55–64) | 76 (73–81) |
| Medical history—no. (%) | ||||
| Myocardial infarction | 1012 (1.6) | 1716 (4.8) | 2689 (4.8) | 1760 (9.9) |
| Heart failure | 363 (0.6) | 1152 (3.2) | 495 (0.9) | 654 (3.7) |
| Valvular heart disease | 221 (0.4) | 446 (1.3) | 257 (0.5) | 250 (1.4) |
| Charlson co-morbidity score | ||||
| 0 Points | 50 114 (79) | 22 707 (64) | 45 555 (81) | 11 033 (62) |
| 1 Point | 6968 (11) | 6289 (18) | 6309 (11) | 3177 (18) |
| ≥2 Points | 6393 (10) | 6654 (19) | 4725 (8) | 3605 (20) |
| Medication history—no. (%) | ||||
| ACE inhibitors or ARBs | 10 702 (17) | 9812 (28) | 10 958 (19) | 4883 (27) |
| Beta-blockers | 11 569 (18) | 8767 (25) | 8846 (16) | 4026 (23) |
| Calcium antagonists | 8768 (14) | 9719 (27) | 8495 (15) | 4618 (26) |
| Medication on day of inclusion—no. (%) | ||||
| QTc-prolonging medicationa | 5913 (14) | 4456 (13) | 3744 (6.6) | 1844 (10) |
| Digoxin | 149 (0.2) | 637 (1.8) | 183 (0.3) | 311 (1.8) |
| Index ECG variables | ||||
| Heart rate—b.p.m.: median (IQR) | 70 (63–79) | 73 (65–82) | 68 (60–78) | 69 (406–431) |
| QTcFram interval—ms: median (IQR) | 420 (409–432) | 420 (408–433) | 415 (404–427) | 419 (406–431) |
| QTcFram interval—ms: mean (SD) | 421 (18) | 421 (20) | 416 (18) | 419 (20) |
| Left ventricular hypertrophy—no. (%) | 1191 (1.9) | 1649 (4.6) | 2945 (5) | 1134 (6.4) |
ms, milliseconds; CI, confidence interval; SD, standard deviation; IQR, inter-quartile range; b.p.m., beats per minute; ACE, angiotensin converting enzyme; ARBs, angiotensin receptor blockers.
aSee Supplementary material online, Table S2 for a comprehensive list.