Table 1.
Characteristics of Training ang Testing sets
| Features | Training set N = 338, N(%)/M (IQR) | Testing set N = 145, N(%)/M (IQR) | Z/χ2 | P values |
|---|---|---|---|---|
| Age, yearsb | 64 (53–73) | 66 (53–74.5) | 0.984 | 0.352 |
| Critical care outcomes | 153 (45.3) | 66 (45.5) | < 0.001 | 0.959 |
| Male | 261 (77.2) | 112 (77.2) | < 0.001 | 0.996 |
| Mode of arrival | ||||
| Ambulance use | 22 (6.5) | 9 (6.2) | 3.37 | 0.498 |
| Transfer from other hospital | 44 (13.0) | 24 (16.5) | ||
| Walk in | 268 (79.3) | 108 (74.5) | ||
| Intra-hospital transfer | 2 (0.6) | 1 (0.7) | ||
| Others | 2 (0.6) | 3 (2.1) | ||
| Historya | 9 (2.7) | 1 (0.7) | 1.948 | 0.163 |
| Diabetes | 94 (27.8) | 37 (25.5) | 0.27 | 0.603 |
| Hypertension | 193 (57.1) | 86 (59.3) | 0.203 | 0.652 |
| Dyslipidemia | 103 (30.5) | 45 (31.0) | 0.015 | 0.902 |
| Smoking | 144 (42.6) | 55 (37.9) | 0.914 | 0.339 |
| Obesitya | 4 (1.2) | 2 (1.4) | 0.032 | 0.859 |
| Number of risk factorsa | ||||
| 0 | 47 (13.9) | 25 (17.2) | 1.58 | 0.812 |
| 1 | 110 (32.5) | 49 (33.8) | ||
| 2 | 119 (35.2) | 44 (30.3) | ||
| 3 | 54 (16.0) | 23 (15.9) | ||
| 4 | 8 (2.4) | 4 (2.8) | ||
| Acute heart failure | 37 (10.9) | 11 (7.6) | 1.28 | 0.258 |
| Type of chest pain | ||||
| Only atypical symptoms | 39 (11.5) | 17 (11.7) | 0.429 | 0.807 |
| Typical and atypical symptoms | 100 (29.6) | 47 (32.4) | ||
| Only typical symptoms | 199 (58.9) | 81 (55.9) | ||
| Duration of chest painb | ||||
| <24 h | 209 (61.8) | 94 (64.8) | 0.718 | 0.698 |
| 24 h-7d | 80 (23.7) | 34 (23.4) | ||
| >7d | 49 (14.5) | 17 (11.7) | ||
| Electrocardiogram findings | ||||
| Normal | 68 (20.1) | 28 (19.3) | 0.048 | 0.976 |
| Nonspecific abnormalities | 135 (39.9) | 58 (40.0) | ||
| Ischemia | 135 (39.9) | 59 (40.7) | ||
| Killip class | ||||
| I | 203 (60.1) | 93 (64.1) | 0.983 | 0.805 |
| II | 68 (20.1) | 24 (16.6) | ||
| III | 23 (6.8) | 10 (6.9) | ||
| IV | 44 (13.0) | 18 (12.4) | ||
| Reperfusion therapyb | ||||
| PCI | 90 (26.6) | 49 (33.8) | 2.585 | 0.275 |
| CABG | 2 (0.6) | 1 (0.7) | ||
| None | 246 (72.8) | 95 (65.5) | ||
| Temperaturea, °C | ||||
| 36.0 ≤ T ≤ 38.0 | 324 (95.9) | 143 (98.6) | 2.418 | 0.12 |
| < 36.0 or > 38.0 | 14 (4.1) | 2 (1.4) | ||
| Heart rate, beats/min | ||||
| 60–100 | 232 (68.6) | 114 (78.6) | 4.976 | 0.026 |
| < 60 or > 100 | 106 (31.4) | 31 (21.4) | ||
| Respiratory rate, beats/min | ||||
| 11–20 | 196 (58.0) | 81 (55.9) | 0.188 | 0.665 |
| ≤ 10 or > 20 | 142 (42.0) | 64 (44.1) | ||
| Systolic pressureb, mmHg | ||||
| ≥ 90 | 308 (91.1) | 137 (94.5) | 1.579 | 0.209 |
| < 90 | 30 (8.9) | 8 (5.5) | ||
| Diastolic pressure, mmHg | ||||
| ≥ 60 | 286 (84.6) | 130 (89.7) | 2.157 | 0.142 |
| < 60 | 52 (15.4) | 15 (10.3) | ||
| Conscious stateb | ||||
| Alert | 336 (99.4) | 143 (98.6) | 0.766 | 0.381 |
| SCr b, μmol/L | ||||
| < 186 | 322 (95.3) | 138 (95.2) | 1.383 | 0.501 |
| 186–451 | 11 (3.3) | 3 (2.1) | ||
| >451 | 5 (1.5) | 4 (2.8) | ||
| cTnI, μg/L | ||||
| < 0.2 | 82 (24.3) | 35 (24.1) | 3.753 | 0.153 |
| 0.2–10.0 | 225 (66.6) | 104 (71.7) | ||
| > 10.0 | 31 (9.2) | 6 (4.1) | ||
| CKMBb, U/L | 28.5 (11 ~ 101.5) | 22 (12 ~ 59) | −0.894 | 0.371 |
| NT-proBNPb, ng/L | 1539.69 (485.25 ~ 3618.75) | 1539.69 (305.85 ~ 3349) | −0.809 | 0.419 |
| CKb, U/L | 310 (95 ~ 910.5) | 190 (78.5 ~ 491) | −2.186 | 0.029 |
PCI percutaneous transluminal coronary intervention, CABG coronary artery bypass grafting, SCr serum creatinine, cTnI cardiac troponin I, CKMB creatine kinase-MB, NT-proBNP N-terminal pro brain natriuretic peptide, CK creatine kinase
aFisher’s test
bWilcoxon’s test