Table 1 Characteristics of the patients in the derivation and internal/external validation cohorts
Derivation (n = 494) | Internal validation (n = 123) | P1-value | External validation (n = 204) | P2-value | |
|---|---|---|---|---|---|
Age < 65 years | 256 (51.8) | 68 (55.3) | 0.491 | 130 (63.7) | 0.004 |
Male, n (%) | 400 (81.0) | 93 (75.6) | 0.184 | 166 (81.4) | 0.902 |
BMI, mean ± SD | 23.7 mea | 23.9 mea | 0.509 | 24.99mea | <0.001 |
Diabetes mellitus, n (%) | 162 (32.8) | 34 (27.6) | 0.272 | 65 (31.9) | 0.811 |
Hypertension, n (%) | 256 (51.8) | 69 (56.1) | 0.395 | 101 (49.5) | 0.578 |
Chronic renal failure, n (%) | 23 (4.7) | 7 (5.7) | 0.633 | 6 (2.9) | 0.302 |
Hypercholesterolemia, n (%) | 68 (13.8) | 14 (11.4) | 0.486 | 38 (18.6) | 0.104 |
Current smoking, n (%) | 226 (45.8) | 49 (39.8) | 0.238 | 116 (56.9) | 0.008 |
Previous event, n (%) | |||||
Stroke | 21 (4.3) | 9 (7.3) | 0.157 | 7 (3.4) | 0.616 |
Variant angina | 7 (1.4) | 1 (0.8) | 1.000 | 2 (1.0) | 1.000 |
Unstable angina | 30 (6.1) | 7 (5.7) | 0.873 | 7 (3.4) | 0.157 |
Myocardial infarction | 45 (9.1) | 8 (6.5) | 0.356 | 6 (2.9) | 0.004 |
CAD | 82 (16.6) | 13 (10.6) | 0.097 | 16 (7.8) | 0.002 |
Heart failure | 16 (3.2) | 0 | 0.052 | 3 (1.5) | 0.305 |
Previous PCI | 73 (14.8) | 15 (12.2) | 0.464 | 16 (7.8) | 0.012 |
Previous CABG | 11 (2.2) | 1 (0.8) | 0.476 | 1 (0.5) | 0.196 |
Family history of CAD, n (%) | 31 (6.3) | 5 (4.1) | 0.518 | 16 (7.8) | 0.452 |
Chest pain, n (%) | |||||
Typical | 350 (70.9) | 84 (68.3) | 0.850 | 151 (74.0) | 0.175 |
Atypical | 57 (11.5) | 15 (12.2) | 14 (6.9) | ||
No chest pain | 87 (17.6) | 24 (19.5) | 39 (19.1) | ||
Other symptom, n (%) | 215 (43.5) | 48 (39.0) | 0.367 | 65 (31.9) | 0.004 |
Radiating pain, n (%) | 139 (28.1) | 27 (22.0) | 0.166 | 59 (28.9) | 0.834 |
Symptom onset to arrival, n (%) | |||||
≤ 6 h | 383 (77.5) | 79 (64.2) | 0.003 | 169 (82.8) | 0.064 |
6-24 h | 63 (12.8) | 30 (24.4) | 26 (12.7) | ||
> 24 h | 48 (9.7) | 14 (11.4) | 9 (4.4) | ||
Ambulance arrival, n (%) | 227 (46.0) | 40 (32.5) | 0.007 | 111 (54.4) | 0.042 |
Hemodynamic instability, n (%) | 88 (17.8) | 20 (16.3) | 0.685 | 35 (17.2) | 0.836 |
Positive baseline biomarker, n (%) | 199 (40.3) | 58 (47.2) | 0.167 | 63 (30.9) | 0.020 |
Location of STE, n (%) | |||||
Anterior | 209 (42.3) | 57 (46.3) | 0.253 | 82 (40.2) | 0.474 |
Inferior | 190 (38.5) | 40 (32.5) | 75 (36.8) | ||
Posterolateral | 19 (3.8) | 9 (7.3) | 6 (2.9) | ||
Diffuse | 76 (15.4) | 17 (13.8) | 41 (20.1) | ||
Height of maximal STE (mm) | 3.1±2.0 | 3.2 ± 2.1 | 0.581 | 3.5 ± 2.1 | 0.049 |
Number of leads with STE | 3.2 ± 1.2 | 3.1 ± 1.1 | 0.505 | 3.5 ± 1.3 | 0.007 |
No reciprocal change, n (%) | 252 (51.0) | 62 (50.4) | 0.904 | 126 (61.8) | 0.010 |
Concave morphology of STE, n (%) | 243 (49.2) | 51 (41.5) | 0.125 | 94 (46.1) | 0.454 |
Q wave, n (%) | 21 (4.3) | 4 (3.3) | 0.800 | 1 (0.5) | 0.007 |
LVH, n (%) | 70 (14.2) | 14 (11.4) | 0.420 | 25 (12.3) | 0.502 |
False-positive STEMI, n (%) | 90 (18.2) | 22 (17.9) | 0.932 | 22 (10.8) | 0.015 |