Table 1.
Baseline characteristics and clinical outcomes in the internal cohort.
| ACS (n = 192) | Non-ACS (n = 363) | P value | |
|---|---|---|---|
| Age, years | 68 (58.5–77) | 73 (60–82) | 0.005 |
| Male sex, n (%) | 152 (79.2) | 214 (59.0) | < 0.001 |
| Past medical history | |||
| Diabetes mellitus, n (%) | 37 (19.3) | 63 (17.4) | 0.577 |
| Hypertension, n (%) | 72 (37.5) | 146 (40.2) | 0.532 |
| Dyslipidemia, n (%) | 14 (7.3) | 17 (4.7) | 0.203 |
| Stable angina, n (%) | 15 (7.8) | 60 (16.5) | 0.004 |
| Old myocardial infarction, n (%) | 24 (12.5) | 66 (18.2) | 0.084 |
| Prior PCI, n (%) | 19 (9.9) | 45 (12.4) | 0.380 |
| Prior CABG, n (%) | 2 (1.0) | 6 (1.7) | 0.566 |
| Intracranial hemorrhage, n (%) | 2 (1.0) | 3 (0.8) | 0.799 |
| Cerebral infarction, n (%) | 11 (5.7) | 20 (5.5) | 0.915 |
| Prior antiplatelet or anticoagulant therapy, n (%) | 12 (6.3) | 40 (11.0) | 0.067 |
| Vital signs | |||
| Heart rate (beats/min) | 74 (60–90) | 88 (72–110) | < 0.001 |
| Systolic blood pressure (mmHg) | 143 (120–169) | 147.5 (122–176) | 0.237 |
| Diastolic blood pressure (mmHg) | 87 (70–102) | 87.5 (72–102) | 0.926 |
| Body temperature (°C) | 36.0 (35.8–36.2) | 36.2 (36.0–36.8) | < 0.001 |
| Blood oxygen saturation (%) | 98 (96–99) | 97 (93–99) | < 0.001 |
| Respiratory rate (times/min) | 20 (18–24) | 20 (18–24) | 0.007 |
| Japan Coma Scale = 0, n (%) | 167 (87.0) | 293 (80.7) | 0.062 |
| Oxygen therapy, n (%) | 69 (35.9) | 143 (39.4) | 0.425 |
| ECG monitoring | |||
| ST elevation, n (%) | 94 (49.0) | 28 (7.7) | < 0.001 |
| ST depression, n (%) | 62 (32.3) | 115 (31.7) | 0.883 |
| ST change, n (%) | 156 (81.3) | 143 (39.4) | < 0.001 |
| Arrhythmia, n (%) | 44 (22.9) | 84 (23.1) | 0.953 |
| Symptoms | |||
| 1. Cold hands, n (%) | 76 (39.6) | 89 (24.5) | < 0.001 |
| 2. Hand moistening, n (%) | 66 (34.4) | 79 (21.7) | 0.001 |
| 3. Dyspnea, n (%) | 47 (24.5) | 121 (33.3) | 0.031 |
| 4. Palpitations, n (%) | 30 (15.6) | 97 (26.7) | 0.003 |
| 5. Throbbing pain, n (%) | 40 (20.8) | 72 (19.8) | 0.780 |
| 6. Sharp/stabbing pain, n (%) | 17 (8.9) | 25 (6.9) | 0.405 |
| 7. Positional chest pain, n (%) | 25 (13.0) | 33 (9.1) | 0.150 |
| 8. Reproduction of chest pain by palpation, n (%) | 6 (3.1) | 11 (3.0) | 0.951 |
| 9. Chest pain with breathing or cough, n (%) | 7 (3.7) | 20 (5.5) | 0.332 |
| 10. Pressing pain, n (%) | 149 (77.6) | 226 (62.3) | < 0.001 |
| 11. Nausea or vomiting, n (%) | 54 (28.1) | 55 (15.2) | < 0.001 |
| 12. Cold sweat, n (%) | 111 (57.8) | 117 (32.2) | < 0.001 |
| 13. Pain radiating to jaw or shoulder, n (%) | 31 (16.2) | 21 (5.8) | < 0.001 |
| 14. Similarity to previous ischemic episode, n (%) | 29 (15.1) | 68 (18.7) | 0.284 |
| 15. Chest pain aggravated by walk, n (%) | 22 (11.5) | 53 (14.6) | 0.303 |
| 16. Worsening pain, n (%) | 52 (27.1) | 99 (27.3) | 0.962 |
| 17. Pain at rest, n (%) | 151 (78.7) | 262 (72.2) | 0.097 |
| 18. Persistent pain, n (%) | 179 (93.2) | 291 (80.2) | < 0.001 |
| 19. Recurrent pain within 24 h, n (%) | 41 (21.4) | 64 (17.6) | 0.287 |
| 20. Chronic pain, n (%) | 16 (8.3) | 58 (16.0) | 0.012 |
| 21. Pain severity (10-point scale) | 6 (0–8) | 4 (0–7) | 0.005 |
Data are presented as median and interquartile range for continuous features.
P-values were calculated using Pearson’s chi-square test or Mann–Whitney U test.
CABG (coronary artery bypass grafting), ECG (electrocardiogram), PCI (percutaneous coronary intervention).