Table 1 Baseline characteristics of the derivation and external validation cohorts
From: Machine learning for diagnosis of myocardial infarction using cardiac troponin concentrations
Derivation cohort | External validation cohort | |||
|---|---|---|---|---|
No myocardial injury at presentation | Myocardial injury at presentation | No myocardial injury at presentation | Myocardial injury at presentation | |
Number of patients | 3,799 | 6,239 | 8,664 | 1,622 |
Age, years | 62 (50–74) | 74 (62–83) | 57 (47–69) | 70 (59–79) |
Sex | ||||
Female | 1,580 (42%) | 3,199 (51%) | 3,048 (35%) | 581 (36%) |
Male | 2,219 (58%) | 3,040 (49%) | 5,616 (65%) | 1,041 (64%) |
Chest pain at presentation | 3,251 (86%) | 4,030 (70%) | 8,551 (99%) | 1,607 (99%) |
Early presenter (≤3 h from symptom onset) | 1071 (28%) | 1,970 (32%) | 3,979 (47%) | 549 (34%) |
Previous medical conditions | ||||
Myocardial infarction | 606 (18%) | 837 (13%) | 1,804 (21%) | 504 (31%) |
Ischemic heart disease | 1,133 (34%) | 2,136 (34%) | 2,447 (28%) | 657 (41%) |
Cerebrovascular disease | 236 (7%) | 626 (10%) | 442 (5%) | 140 (9%) |
Diabetes mellitus | 513 (16%) | 919 (15%) | 1,267 (15%) | 376 (23%) |
Previous revascularization | ||||
PCI | 360 (11%) | 560 (9%) | 1,792 (21%) | 438 (27%) |
CABG | 178 (5%) | 161 (3%) | 555 (6%) | 187 (12%) |
Medications at presentation | ||||
Aspirin | 720 (30%) | 2,267 (36%) | 2,972 (34%) | 744 (46%) |
Dual antiplatelet therapya | 115 (5%) | 309 (5%) | 1,804 (27%) | 506 (42%) |
ACE or ARB | 745 (31%) | 2,681 (43%) | 2,474 (36%) | 626 (50%) |
Beta-blocker | 584 (25%) | 2,156 (35%) | 2,076 (30%) | 520 (41%) |
Electrocardiogram resultb | ||||
Normal | 3,279 (87%) | 3,308 (64%) | 2,947 (44%) | 759 (63%) |
Myocardial ischemia | 458 (14%) | 1,351 (26%) | 797 (9%) | 599 (37%) |
ST-segment elevation | 93 (3%) | 196 (4%) | 88 (1%) | 20 (2%) |
Physiological parameters | ||||
Heart rate, beats per min | 77 (65–90) | 81 (68–99) | 74 (65–85) | 77 (66–90) |
Systolic blood pressure, mm Hg | 137 (121–153) | 138 (120–157) | 140 (125–156) | 142 (127–160) |
Hematology and clinical chemistry measurements | ||||
Hemoglobin, g l−1 | NA | 133 (118–146) | 143 (133–153) | 140 (126–152) |
eGFR, ml min−1 1.73 m2 | 86 (69–99) | 66 (44–85) | 87 (72–96) | 73 (55–89) |
Presentation high-sensitivity cardiac troponin I, ng l−1 | 3 (2–7) | 85 (41–320) | 3 (2–6) | 144 (53–614) |
Serial high-sensitivity cardiac troponin I, ng l−1 | 4 (2–8) | 170 (51–1,422) | 3 (2–6) | 200 (61–894) |
Peak high-sensitivity cardiac troponin I, ng l−1 | 5 (3–11) | 209 (53–1,786) | 3 (2–7) | 263 (61–1,118) |
Adjudicated diagnosis | ||||
Type 1, 4b or 4c myocardial infarction | 132 (3%) | 3,094 (49%) | 267 (3%) | 1,032 (64%) |
Type 2 myocardial infarction | 33 (1%) | 802 (13%) | 132 (2%) | 169 (10%) |
Nonischemic myocardial injury | 21 (1%) | 2,343 (38%) | 180 (2%) | 252 (16%) |
