Table 1 Baseline characteristics and clinical outcomes in the internal cohort.

From: Prehospital diagnostic algorithm for acute coronary syndrome using machine learning: a prospective observational study

 

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

  1. Data are presented as median and interquartile range for continuous features.
  2. P-values were calculated using Pearson’s chi-square test or Mann–Whitney U test.
  3. CABG (coronary artery bypass grafting), ECG (electrocardiogram), PCI (percutaneous coronary intervention).