Table 1.
Baseline characteristics of the study population referred for an ETT
| Characteristic | Total | Men | Women | P-value |
|---|---|---|---|---|
| n = 9569 | n= 5094 | n=4475 | ||
| Age (years) | 56 (48, 65) | 55 (47, 65) | 57 (49, 66) | <0.01 |
| Current smoking | 1348 (14.1) | 729 (14.3) | 619 (13.8) | 0.52 |
| Clinical History | ||||
| Diabetes Mellitus | 1341 (14.1) | 781 (15.3) | 560 (12.5) | <0.01 |
| Hypertension | 4664 (48.7) | 2463 (48.4) | 2201 (49.2) | 0.43 |
| Hyperlipidemia | 6083 (63.6) | 3279 (64.4) | 2804 (62.7) | 0.09 |
| Coronary artery disease | 1305 (13.7) | 972 (19.1) | 333 (7.4) | <0.01 |
| Chronic obstructive pulmonary disease | 463 (4.8) | 234 (4.6) | 229 (5.1) | 0.23 |
| Peripheral vascular disease | 175 (1.8) | 122 (2.4) | 53 (1.2) | <0.01 |
| Cerebral vascular disease | 237 (2.5) | 115 (2.3) | 122 (2.7) | 0.14 |
| Obstructive sleep apnea | 417 (4.4) | 273 (5.4) | 144 (3.2) | <0.01 |
| Cancer | 468 (4.9) | 238 (4.7) | 230 (5.1) | 0.29 |
| Depression | 1485 (15.5) | 561 (11.0) | 924 (20.6) | <0.01 |
| Family history of coronary disease | 3498 (36.6) | 1738 (34.1) | 1760 (39.3) | <0.01 |
| Reason for ETT referral | ||||
| Atypical chest pain | 4489 (47.0) | 2386 (46.8) | 2103 (47.9) | 0.49 |
| Chest pain | 1679 (17.6) | 835 (16.4) | 844 (18.9) | <0.01 |
| Dyspnea on exertion | 862 (9.0) | 453 (8.9) | 409 (9.1) | 0.68 |
| Other or missing | 2541 (26.5) | 1288 (25.3) | 1253 (28.0) | <0.01 |
| Exercise Treadmill Variables | ||||
| Chest Pain | 868 (9.1) | 385 (7.6) | 483 (10.8) | <0.01 |
| Exercise Capacity <85%† | 2330 (24.4) | 1084 (21.3) | 1246 (27.8) | <0.01 |
| Ischemic ST segment change | 1905 (19.9) | 1008 (19.8) | 897 (20.0) | 0.77 |
| Heart rate recovery ≤12 bpm‡ | 2947 (30.8) | 1486 (29.2) | 1461 (32.6) | <0.01 |
| Chronotropic incompetence <0.8 | 2288 (23.9) | 1173 (23.0) | 1115 (24.9) | 0.03 |
| Maximal heart rate | 155 (142,168) | 155 (142,169) | 155 (142,166) | <0.01 |
| Maximal systolic blood pressure | 168 (152,182) | 170 (160,188) | 164 (150,180) | <0.01 |
| Maximal diastolic blood pressure | 80 (76,90) | 82 (78,90) | 80 (76,90) | <0.01 |
| Ectopy in recovery§ | 194 (2.0) | 124 (2.4) | 69 (1.5) | <0.01 |
| Medications | ||||
| Aspirin | 2541 (26.6) | 1531 (30.1) | 1010 (22.6) | <0.01 |
| Beta-blockers | 2287 (24.0) | 1258 (24.7) | 1029 (23.0) | 0.05 |
| Diuretics | 1819 (19.1) | 780 (15.3) | 1039 (23.2) | <0.01 |
| Calcium channel blockers | 658 (6.9) | 335 (6.7) | 323 (7.2) | 0.22 |
| ACE and/or ARB | 1777 (18.6) | 1091 (21.4) | 686 (15.3) | <0.01 |
| Statins | 2234 (23.4) | 1424 (27.9) | 810 (18.1) | <0.01 |
Continuous variables shown as median (25th, 75th percentiles)
Categorical variables are shown as exact count (percent)
*
ACE = angiotensin converting enzyme; ARB= angiotensin receptor blocker; ETT = exercise treadmill testing;
‡
A cutoff value of 12 beats/minute or less for heart rate recovery was considered abnormal.6
§
Presence of 6 or more premature ventricular beats per minute in recovery. 5