Baseline characteristics of incident AF cohort
| Primary care AF | Hospital AF | Complete AF cohort | p Value† | ||
|---|---|---|---|---|---|
| Primary discharge dx | Non-primary discharge dx | ||||
| Total | 35 788 (39.0) | 13 474 (14.7) | 42 445 (46.3) | 91 707 (100.0) | |
| Age (mean±SD), years | 74.9±10.7 | 73.2±12.0 | 78.8±10.8 | 76.4±11.1 | <0.001 |
| Age 45–49 | 605 (1.7) | 464 (3.4) | 423 (1.0) | 1492 (1.6) | |
| Age 50–54 | 1019 (2.8) | 614 (4.6) | 681 (1.6) | 2314 (2.5) | |
| Age 55–59 | 1757 (4.9) | 982 (7.3) | 1306 (3.1) | 4045 (4.4) | |
| Age 60–64 | 2845 (7.9) | 1331 (9.9) | 2330 (5.5) | 6506 (7.1) | |
| Age 65–69 | 4024 (11.2) | 1561 (11.6) | 3443 (8.1) | 9028 (9.8) | |
| Age 70–74 | 5536 (15.5) | 1761 (13.1) | 5020 (11.8) | 12 317 (13.4) | |
| Age 75–79 | 6663 (18.6) | 2177 (16.2) | 6723 (15.8) | 15 563 (17.0) | |
| Age 80–84 | 6538 (18.3) | 2071 (15.4) | 8368 (19.7) | 16 977 (18.5) | |
| Age 85–89 | 4457 (12.5) | 1511 (11.2) | 7731 (18.2) | 13 699 (14.9) | |
| Age 90+ | 2344 (6.5) | 1002 (7.4) | 6420 (15.1) | 9766 (10.6) | |
| Female gender | 16 838 (47.0) | 6991 (51.9) | 21 968 (51.8) | 45 797 (49.9) | <0.001 |
| Body mass index (mean±SD) | 27.8±5.7 | 27.8±6.0 | 26.8±5.8 | 27.3±5.8 | <0.001 |
| <18.5 (underweight) | 582 (1.8) | 263 (2.2) | 1484 (4.2) | 2329 (2.9) | |
| 18.5 to <25 (normal weight) | 9768 (30.9) | 3740 (31.9) | 12 840 (36.0) | 26 348 (33.4) | |
| 25 to <30 (overweight) | 12 162 (38.5) | 4434 (37.8) | 12 699 (35.6) | 29 295 (37.1) | |
| 30 to <35 (stage 1 obesity) | 5942 (18.8) | 2064 (17.6) | 5771 (16.2) | 13 777 (17.4) | |
| 35+ (stage 2 obesity) | 3129 (9.9) | 1236 (10.5) | 2874 (8.1) | 7239 (9.2) | |
| Unknown | 4205 (11.7) | 1737 (12.9) | 6777 (16.0) | 12 719 (13.9) | |
| Smoking status | |||||
| Never | 18 295 (53.2) | 6685 (52.0) | 19 729 (48.9) | 44 709 (51.0) | <0.001 |
| Ex | 12 520 (36.4) | 4443 (34.5) | 14 736 (36.5) | 31 699 (36.2) | <0.001 |
| Current | 3559 (10.4) | 1735 (13.5) | 5911 (14.6) | 11 205 (12.8) | <0.001 |
| Unknown | 1414 (4.0) | 611 (4.5) | 2069 (4.9) | 4094 (4.5) | <0.001 |
| Socioeconomic status (SES) | |||||
| 1st quintile (least deprived) | 8477 (24.3) | 2948 (22.4) | 8209 (19.7) | 19 634 (21.8) | <0.001 |
| 2nd quintile | 9103 (26.0) | 3167 (24.1) | 9786 (23.4) | 22 056 (24.5) | <0.001 |
| 3rd quintile | 7494 (21.4) | 2661 (20.2) | 8728 (20.9) | 18 883 (21.0) | 0.014 |
| 4th quintile | 5873 (16.8) | 2428 (18.4) | 8043 (19.3) | 16 344 (18.2) | <0.001 |
| 5th quintile (most deprived) | 4007 (11.5) | 1962 (14.9) | 6979 (16.7) | 12 948 (14.4) | <0.001 |
| Unknown SES | 834 (2.3) | 308 (2.3) | 700 (1.6) | 1842 (2.0) | <0.001 |
| Ethnic origin‡ | |||||
| Asian | 75 (0.2) | 32 (0.2) | 84 (0.2) | 191 (0.2) | 0.661 |
| Black | 93 (0.3) | 54 (0.4) | 144 (0.3) | 291 (0.3) | 0.024 |
| Mixed | 27 (0.1) | 11 (0.1) | 38 (0.1) | 76 (0.1) | 0.795 |
| South Asian | 142 (0.4) | 79 (0.6) | 242 (0.6) | 463 (0.5) | <0.001 |
| White | 28 405 (85.0) | 11 709 (86.9) | 36 447 (85.9) | 76 561 (85.7) | <0.001 |
| Other | 147 (0.4) | 62 (0.5) | 214 (0.5) | 423 (0.5) | 0.157 |
| Unknown | 4528 (13.5) | 1527 (11.3) | 5276 (12.4) | 11 331 (12.7) | <0.001 |
| Comorbidities | |||||
| Hypercholesterolaemia | 11 907 (33.3) | 4458 (33.1) | 13 510 (31.8) | 29 875 (32.6) | <0.001 |
| Lipid lowering drugs | 12 733 (35.6) | 4943 (36.7) | 16 583 (39.1) | 34 259 (37.4) | <0.001 |
| Heart failure | 2894 (8.1) | 1093 (8.1) | 5659 (13.3) | 9646 (10.5) | <0.001 |
| Hypertension | 20 609 (57.6) | 7395 (54.9) | 25 496 (60.1) | 53 500 (58.3) | <0.001 |
| Diabetes | 5119 (14.3) | 2010 (14.9) | 7857 (18.5) | 14 986 (16.3) | <0.001 |
| Stroke/TIA | 4209 (11.8) | 1396 (10.4) | 6517 (15.4) | 12 122 (13.2) | <0.001 |
| Thromboembolism | 403 (1.1) | 139 (1.0) | 685 (1.6) | 1227 (1.3) | <0.001 |
| Myocardial Infarction | 2717 (7.6) | 1235 (9.2) | 5133 (12.1) | 9085 (9.9) | <0.001 |
| Coronary arterial disease without myocardial infarction | 4279 (12.0) | 1824 (13.5) | 6646 (15.7) | 12 749 (13.9) | <0.001 |
| Peripheral vascular disease | 3018 (8.4) | 1152 (8.5) | 5030 (11.9) | 9200 (10.0) | <0.001 |
| Coronary artery bypass graft | 374 (1.0) | 158 (1.2) | 405 (1.0) | 937 (1.0) | 0.076 |
| Stent | 610 (1.7) | 315 (2.3) | 927 (2.2) | 1852 (2.0) | <0.001 |
| Chronic pulmonary disease | 7324 (20.5) | 3117 (23.1) | 11 136 (26.2) | 21 577 (23.5) | <0.001 |
| Cerebrovascular disease | 3847 (10.7) | 1335 (9.9) | 6500 (15.3) | 11 682 (12.7) | <0.001 |
| Dementia | 672 (1.9) | 309 (2.3) | 2369 (5.6) | 3350 (3.7) | <0.001 |
| Connective tissue disease | 2055 (5.7) | 850 (6.3) | 3219 (7.6) | 6124 (6.7) | <0.001 |
| Charlson index | 1.4±1.6 | 1.5±1.7 | 2.1±2.0 | 1.7±1.9 | <0.001 |
†Testing differences between any of the three groups: (primary care AF, hospital AF with primary discharge diagnosis, and hospital AF with non-primary discharge diagnosis) using an F-Test for comparison of means, and Fisher's exact test for comparison of proportions.
‡Available for cohort members with ≥1 hospitalisation between 1997 and 2013.
AF, atrial fibrillation; dx, diagnosis; TIA, transient ischaemic attack.