Table 1.
Baseline characteristics of adults with atrial fibrillation between January 2006 – June 2009 with no known heart failure or prior digoxin use, overall and stratified by new digoxin use during follow-up, in the full cohort and the age, gender and high-dimensional propensity score-matched cohort.
| Full Digoxin Cohort | Age, Gender, and High-dimensional Propensity Score Matched Cohort (1:3) |
|||||||
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| Characteristic | Overall (N=27,288) |
Digoxin Users (N=4858) |
Non-users (N=22,430) |
P value | Overall (N=14,787) |
Digoxin Users (N=4231) |
Matched Non-users (N=10,556) |
P value |
| Age, year, mean (SD) | 70.7 (12.9) | 71.9 (11.9) | 70.5 (13.1) | <0.001 | 71.7 (11.3) | 72.1 (11.4) | 71.6 (11.2) | 0.01 |
| Gender, N (%) | ||||||||
| Men | 15,191 (55.7) | 2441 (50.2) | 12,750 (56.8) | <0.001 | 7714 (52.2) | 2164 (51.1) | 5550 (52.6) | 0.12 |
| Women | 12,097 (44.3) | 2417 (49.8) | 9680 (43.2) | <0.001 | 7073 (47.8) | 2067 (48.9) | 5006 (47.4) | 0.12 |
| Race, N (%) | <0.001 | 0.43 | ||||||
| White | 20,969 (76.8) | 3932 (80.9) | 17,037 (76.0) | 11,790 (79.7) | 3399 (80.3) | 8391 (79.5) | ||
| Black | 1582 (5.8) | 297 (6.1) | 1285 (5.7) | 858 (5.8) | 249 (5.9) | 609 (5.8) | ||
| Native American | 58 (0.2) | 12 (0.2) | 46 (0.2) | 36 (0.2) | 11 (0.3) | 25 (0.2) | ||
| Asian | 2043 (7.5) | 257 (5.3) | 1786 (8.0) | 891 (6.0) | 233 (5.5) | 658 (6.2) | ||
| Other/unknown | 2636 (9.7) | 360 (7.4) | 2276 (10.1) | 1212 (8.2) | 339 (8.0) | 873 (8.3) | ||
| Hispanic ethnicity, N (%) | 3197 (11.7) | 507 (10.4) | 2690 (12.0) | 0.002 | 1550 (10.5) | 445 (10.5) | 1105 (10.5) | 0.93 |
| Socioeconomic status, N (%) | ||||||||
| Low annual household income | 3514 (12.9) | 722 (14.9) | 2792 (12.4) | <0.001 | 1925 (13.0) | 610 (14.4) | 1315 (12.5) | 0.001 |
| Low educational attainment | 5778 (21.2) | 1110 (22.8) | 4668 (20.8) | 0.002 | 3111 (21.0) | 937 (22.1) | 2174 (20.6) | 0.04 |
| Cardiovascular disease, N (%) | ||||||||
| Acute myocardial infarction | 999 (3.7) | 125 (2.6) | 874 (3.9) | <0.001 | 454 (3.1) | 110 (2.6) | 344 (3.3) | 0.04 |
| Unstable angina | 613 (2.2) | 85 (1.7) | 528 (2.4) | 0.010 | 279 (1.9) | 74 (1.7) | 205 (1.9) | 0.44 |
| Ischemic stroke | 1037 (3.8) | 155 (3.2) | 882 (3.9) | 0.01 | 508 (3.4) | 142 (3.4) | 366 (3.5) | 0.74 |
| Transient ischemic attack | 728 (2.7) | 116 (2.4) | 612 (2.7) | 0.18 | 369 (2.5) | 100 (2.4) | 269 (2.5) | 0.51 |
| Intracranial hemorrhage | 141 (0.5) | 20 (0.4) | 121 (0.5) | 0.26 | 66 (0.4) | 17 (0.4) | 49 (0.5) | 0.61 |
| Peripheral arterial disease | 949 (3.5) | 160 (3.3) | 789 (3.5) | 0.44 | 433 (2.9) | 141 (3.3) | 292 (2.8) | 0.06 |
| Valvular heart disease | 328 (1.2) | 43 (0.9) | 285 (1.3) | 0.03 | 134 (0.9) | 35 (0.8) | 99 (0.9) | 0.52 |
| Ventricular arrhythmias, N (%) | ||||||||
| Ventricular tachycardia | 87 (0.3) | 11 (0.2) | 76 (0.3) | 0.21 | 43 (0.3) | 11 (0.3) | 32 (0.3) | 0.66 |
| Ventricular fibrillation | 6 (0.0) | 0 (0.0) | 6 (0.0) | 0.25 | 4 (0.0) | 0 (0.0) | 4 (0.0) | 0.21 |
| Cardiovascular procedure history, N (%) | ||||||||
| Percutaneous coronary intervention | 1175 (4.3) | 150 (3.1) | 1025 (4.6) | <0.001 | 527 (3.6) | 138 (3.3) | 389 (3.7) | 0.21 |
| Coronary artery bypass surgery | 825 (3.0) | 81 (1.7) | 744 (3.3) | <0.001 | 316 (2.1) | 75 (1.8) | 241 (2.3) | 0.05 |
| Other cardiovascular risk factors, N (%) | ||||||||
| Hypertension | 21,163 (77.6) | 3707 (76.3) | 17,456 (77.8) | 0.02 | 11,573 (78.3) | 3260 (77.1) | 8313 (78.8) | 0.02 |
| Diabetes mellitus | 6498 (23.8) | 1116 (23.0) | 5382 (24.0) | 0.13 | 3416 (23.1) | 974 (23.0) | 2442 (23.1) | 0.88 |
| Dyslipidemia | 15,112 (55.4) | 2517 (51.8) | 12,595 (56.2) | <0.001 | 8006 (54.1) | 2249 (53.2) | 5757 (54.5) | 0.13 |
| Other coexisting medical illnesses, N (%) | ||||||||
| Dementia | 1470 (5.4) | 248 (5.1) | 1222 (5.4) | 0.34 | 721 (4.9) | 209 (4.9) | 512 (4.9) | 0.82 |
| Depression | 4757 (17.4) | 860 (17.7) | 3897 (17.4) | 0.58 | 2626 (17.8) | 744 (17.6) | 1882 (17.8) | 0.73 |
| Thyroid disease | 4196 (15.4) | 765 (15.7) | 3431 (15.3) | 0.43 | 2368 (16.0) | 671 (15.9) | 1697 (16.1) | 0.75 |
| Gastrointestinal bleeding | 596 (2.2) | 96 (2.0) | 500 (2.2) | 0.27 | 284 (1.9) | 82 (1.9) | 202 (1.9) | 0.92 |
| Other bleeding | 95 (0.3) | 25 (0.5) | 70 (0.3) | 0.03 | 55 (0.4) | 24 (0.6) | 31 (0.3) | 0.01 |
| Cancer | 1761 (6.5) | 371 (7.6) | 1390 (6.2) | <0.001 | 947 (6.4) | 312 (7.4) | 635 (6.0) | 0.002 |
| Lung disease | 6162 (22.6) | 1253 (25.8) | 4909 (21.9) | <0.001 | 3322 (22.5) | 1036 (24.5) | 2286 (21.7) | <0.001 |
| Liver disease | 618 (2.3) | 95 (2.0) | 523 (2.3) | 0.11 | 304 (2.1) | 83 (2.0) | 221 (2.1) | 0.61 |
| Medications, N (%) | ||||||||
| Warfarin | 9363 (34.3) | 1517 (31.2) | 7846 (35.0) | <0.001 | 4989 (33.7) | 1420 (33.6) | 3569 (33.8) | 0.77 |
| Alpha-adrenergic receptor antagonist | 3821 (14.0) | 615 (12.7) | 3206 (14.3) | 0.003 | 1941 (13.1) | 555 (13.1) | 1386 (13.1) | 0.98 |
| Angiotensin converting enzyme inhibitor | 9873 (36.2) | 1628 (33.5) | 8245 (36.8) | <0.001 | 5288 (35.8) | 1442 (34.1) | 3846 (36.4) | 0.007 |
| Angiotensin receptor blocker | 2465 (9.0) | 402 (8.3) | 2063 (9.2) | 0.04 | 1313 (8.9) | 364 (8.6) | 949 (9.0) | 0.45 |
| Diuretic | 10,399 (38.1) | 1793 (36.9) | 8606 (38.4) | 0.06 | 5683 (38.4) | 1576 (37.2) | 4107 (38.9) | 0.06 |
| Beta-blocker | 15,926 (58.4) | 2557 (52.6) | 13,369 (59.6) | <0.001 | 8497 (57.5) | 2351 (55.6) | 6146 (58.2) | 0.003 |
| Aldosterone receptor antagonist | 345 (1.3) | 58 (1.2) | 287 (1.3) | 0.63 | 186 (1.3) | 49 (1.2) | 137 (1.3) | 0.49 |
| Calcium channel blocker | 7920 (29.0) | 1369 (28.2) | 6551 (29.2) | 0.15 | 4194 (28.4) | 1224 (28.9) | 2970 (28.1) | 0.33 |
| Nitrates | 2326 (8.5) | 346 (7.1) | 1980 (8.8) | <0.001 | 1136 (7.7) | 304 (7.2) | 832 (7.9) | 0.15 |
| Hydralazine | 504 (1.8) | 76 (1.6) | 428 (1.9) | 0.11 | 237 (1.6) | 67 (1.6) | 170 (1.6) | 0.91 |
| Statin | 12,173 (44.6) | 1960 (40.3) | 10,213 (45.5) | <0.001 | 6385 (43.2) | 1767 (41.8) | 4618 (43.7) | 0.03 |
| Other lipid lowering agent | 1185 (4.3) | 176 (3.6) | 1009 (4.5) | 0.007 | 619 (4.2) | 164 (3.9) | 455 (4.3) | 0.23 |
| Antiplatelet agent | 2018 (7.4) | 283 (5.8) | 1735 (7.7) | <0.001 | 960 (6.5) | 260 (6.1) | 700 (6.6) | 0.28 |
| Diabetes medications | 4183 (15.3) | 692 (14.2) | 3491 (15.6) | 0.02 | 2127 (14.4) | 606 (14.3) | 1521 (14.4) | 0.89 |
| Baseline CHADS2 score, mean (SD) | 1.56 (1.04) | 1.55 (1.00) | 1.56 (1.05) | 0.59 | 1.56 (1.01) | 1.56 (1.00) | 1.56 (1.02) | 0.89 |
| Body mass index, kg/m2, N (%) | <0.001 | <0.001 | ||||||
| <25 | 5959 (21.8) | 1012 (20.8) | 4947 (22.1) | 2865 (19.4) | 908 (21.5) | 1957 (18.5) | ||
| 25–29 | 7077 (25.9) | 1179 (24.3) | 5898 (26.3) | 3421 (23.1) | 1065 (25.2) | 2356 (22.3) | ||
| 30–39 | 5783 (21.2) | 1008 (20.7) | 4775 (21.3) | 2846 (19.2) | 900 (21.3) | 1946 (18.4) | ||
| >=40 | 1197 (4.4) | 245 (5.0) | 952 (4.2) | 577 (3.9) | 215 (5.1) | 362 (3.4) | ||
| Missing | 7272 (26.6) | 1414 (29.1) | 5858 (26.1) | 5078 (34.3) | 1143 (27.0) | 3935 (37.3) | ||
| Systolic blood pressure, mmHg, N (%) | <0.001 | <0.001 | ||||||
| < 120 | 6926 (25.4) | 1434 (29.5) | 5492 (24.5) | 3345 (22.6) | 1285 (30.4) | 2060 (19.5) | ||
| 120–129 | 4886 (17.9) | 764 (15.7) | 4122 (18.4) | 2281 (15.4) | 704 (16.6) | 1577 (14.9) | ||
| 130–139 | 4704 (17.2) | 724 (14.9) | 3980 (17.7) | 2350 (15.9) | 635 (15.0) | 1715 (16.2) | ||
| >=140 | 4266 (15.6) | 648 (13.3) | 3618 (16.1) | 2208 (14.9) | 569 (13.4) | 1639 (15.5) | ||
| Missing | 6506 (23.8) | 1288 (26.5) | 5218 (23.3) | 4603 (31.1) | 1038 (24.5) | 3565 (33.8) | ||
| Diastolic blood pressure, mmHg, N (%) | <0.001 | <0.001 | ||||||
| < 80 | 14,687 (53.8) | 2404 (49.5) | 12,283 (54.8) | 7016 (47.4) | 2167 (51.2) | 4849 (45.9) | ||
| 80–84 | 2912 (10.7) | 510 (10.5) | 2402 (10.7) | 1502 (10.2) | 453 (10.7) | 1049 (9.9) | ||
| 85–89 | 1480 (5.4) | 274 (5.6) | 1206 (5.4) | 749 (5.1) | 248 (5.9) | 501 (4.7) | ||
| >=90 | 1703 (6.2) | 383 (7.9) | 1320 (5.9) | 918 (6.2) | 326 (7.7) | 592 (5.6) | ||
| Missing | 6506 (23.8) | 1287 (26.5) | 5219 (23.3) | 4602 (31.1) | 1037 (24.5) | 3565 (33.8) | ||
| Baseline laboratory results | ||||||||
| Estimated glomerular filtration rate category, ml/min/1.73 m2, N (%) | <0.001 | 0.001 | ||||||
| 90–150 | 3305 (12.1) | 521 (10.7) | 2784 (12.4) | 1296 (8.8) | 431 (10.2) | 865 (8.2) | ||
| 60–89 | 11,819 (43.3) | 2156 (44.4) | 9663 (43.1) | 6568 (44.4) | 1881 (44.5) | 4687 (44.4) | ||
| 45–59 | 6031 (22.1) | 1129 (23.2) | 4902 (21.9) | 3552 (24.0) | 1000 (23.6) | 2552 (24.2) | ||
| 30–44 | 2686 (9.8) | 511 (10.5) | 2175 (9.7) | 1486 (10.0) | 428 (10.1) | 1058 (10.0) | ||
| <30 | 817 (3.0) | 125 (2.6) | 692 (3.1) | 412 (2.8) | 111 (2.6) | 301 (2.9) | ||
| Missing | 2630 (9.6) | 416 (8.6) | 2214 (9.9) | 1473 (10.0) | 380 (9.0) | 1093 (10.4) | ||