Table 1.
Baseline characteristics in the derivation and validation cohort.
| Derivation cohort (n = 8082) | Validation cohort (n = 3464) | P | |
|---|---|---|---|
| Age in years, median (IQR) | 57.6 (50.7–66.1) | 57.9 (50.9–66.0) | 0.536 |
| Age group, n (%) | 0.597 | ||
| <40 | 331 (4.1) | 148 (4.3) | |
| 40–59 | 4369 (54.1) | 1833 (52.9) | |
| 60–69 | 1952 (24.2) | 857 (24.7) | |
| 70–79 | 1016 (12.6) | 461 (13.3) | |
| > = 80 | 414 (5.1) | 165 (4.8) | |
| Gender, n (%) | 0.361 | ||
| Male | 6885 (85.2) | 2928 (84.5) | |
| Female | 1197 (14.8) | 536 (15.5) | |
| Ethnicity, n (%) | 0.072 | ||
| Chinese | 4960 (61.4) | 2167 (62.6) | |
| Malay | 1622 (20.1) | 722 (20.8) | |
| Indian | 1360 (16.8) | 515 (14.9) | |
| Others | 140 (1.7) | 60 (1.7) | |
| History of diabetes, n (%) | 2273 (28.1) | 980 (28.3) | 0.853 |
| History of hypertension, n (%) | 4220 (52.2) | 1796 (51.9) | 0.72 |
| History of dyslipidemia, n (%) | 3712 (46.0) | 1588 (45.9) | 0.902 |
| History of IHD, n (%) | 1212 (15.0) | 532 (15.4) | 0.63 |
| Current smoker, n (%) | 3926 (49.1) | 1718 (50.1) | 0.34 |
| BMI in kg/m2, median (IQR) | 24.6 (22.4–27.3) | 24.4 (22.2–27.1) | 0.034 |
| BMI group, n (%) | 0.041 | ||
| < = 23 | 2255 (30.9) | 1032 (32.9) | |
| >23 | 5041 (69.1) | 2101 (67.1) | |
| Killip class on admission, n (%) | 0.297 | ||
| I | 6703 (83.0) | 2849 (82.3) | |
| II | 385 (4.8) | 158 (4.6) | |
| III | 288 (3.6) | 148 (4.3) | |
| IV | 705 (8.7) | 309 (8.9) | |
| Cardiac arrest in ambulance/on admission, n (%) | 319 (4.0) | 155 (4.5) | 0.19 |
| Anterior STEMI on admission, n (%) | 4022 (49.8) | 1736 (50.1) | 0.73 |
| Creatinine on admission in µmol/L, median (IQR) | 90 (76–109) | 90 (77–109) | 0.718 |
| Creatinine group, n (%) | 0.615 | ||
| <70 | 1177 (14.6) | 519 (15.1) | |
| 70–105 | 4622 (57.3) | 1944 (56.5) | |
| 106–140 | 1501 (18.6) | 675 (19.6) | |
| 141–176 | 364 (4.5) | 152 (4.4) | |
| 177–353 | 269 (3.3) | 100 (2.9) | |
| > = 354 | 135 (1.7) | 54 (1.6) | |
| Hemoglobin on admission in g/dL, median (IQR) | 14.6 (13.5–15.7) | 14.7 (13.4–15.7) | 0.58 |
| Hemoglobin group, n (%) | 0.633 | ||
| <10 | 185 (2.3) | 87 (2.5) | |
| 10–11 | 547 (6.8) | 258 (7.5) | |
| 12–13 | 2031 (25.2) | 863 (25.1) | |
| 14–16 | 3693 (45.8) | 1563 (45.4) | |
| > = 17 | 1609 (20.0) | 674 (19.6) | |
| Elevated first troponin T/I on admission, n (%) | 3938 (48.7) | 1649 (47.6) | 0.269 |
| Blood sugar within 72 h from STEMI onset in mmol/L, median (IQR) | 8.5 (6.7–12.2) | 8.4 (6.7–12.1) | 0.287 |
| Total cholesterol within 72 h from STEMI onset in mmol/L, median (IQR) | 5.1 (4.3–6.0) | 5.1 (4.3–6.0) | 0.514 |
| HDL cholesterol within 72 h from STEMI onset in mmol/L, median (IQR) | 1.0 (0.9–1.2) | 1.0 (0.9–1.2) | 0.431 |
| LDL cholesterol within 72 h from STEMI onset in mmol/L, median (IQR) | 3.4 (2.6–4.1) | 3.3 (2.6–4.1) | 0.264 |
| Triglyceride within 72 h from STEMI onset in mmol/L, median (IQR) | 1.4 (1.0–2.0) | 1.4 (1.0–2.0) | 0.98 |
| HbA1c on admission in %, median (IQR) | 6.1 (5.7–7.6) | 6.1 (5.7–7.7) | 0.97 |
| S2B time in minutes, median (IQR) | 183 (120–310) | 180 (119–298) | 0.118 |
| S2B time group, n (%) | 0.205 | ||
| < = 180 | 3738 (49.2) | 1654 (50.5) | |
| >180 | 3865 (50.8) | 1622 (49.5) | |
| D2B in minutes, median (IQR) | 65 (50–88) | 64 (49–87) | 0.435 |
| Lowest LVEF during hospitalization in %, median (IQR) | 45 (35–55) | 45 (35–55) | 0.874 |
| LVEF group, n (%) | 0.372 | ||
| <40 | 2244 (29.5) | 963 (30.0) | |
| 40–50 | 3153 (41.5) | 1286 (40.1) | |
| >50 | 2201 (29.0) | 960 (29.9) | |
| Aspirin given during hospitalization, n (%) | 7710 (95.4) | 3278 (94.6) | 0.078 |
| Beta blocker given during hospitalization, n (%) | 6793 (84.1) | 2854 (82.4) | 0.027 |
| Lipid lowering therapy/statin given during hospitalization, n (%) | 7710 (95.4) | 3282 (94.8) | 0.134 |
| ACEI/ARB given during hospitalization, n (%) | 5932 (73.4) | 2537 (73.2) | 0.86 |
| Other anti-platelet given during hospitalization, n (%) | 7800 (96.5) | 3327 (96.1) | 0.22 |
| Aspirin given at discharge among those discharged alive, n (%) | 7323 (97.1) | 3102 (97.0) | 0.935 |
| Beta blocker given at discharge among those discharged alive, n (%) | 6592 (87.4) | 2766 (86.5) | 0.229 |
| Lipid lowering therapy/statin given at discharge among those discharged alive, n (%) | 7377 (97.8) | 3141 (98.3) | 0.115 |
| ACEI/ARB given at discharge among those discharged alive, n (%) | 5568 (73.8) | 2390 (74.8) | 0.299 |
| Other anti-platelet given at discharge among those discharged alive, n (%) | 7405 (98.1) | 3150 (98.5) | 0.163 |
IQR: interquartile range; IHD: ischemic heart disease; BMI: body mass index; STEMI: ST-segment elevation myocardial infarction; S2B: symptom-to-balloon; D2B: door-to-balloon; LVEF: left ventricular ejection fraction; ACE: angiotensin converting enzyme inhibitor; ARB: angiotensin receptor blocker.