Table 1 Characteristics of participants in the training and test datasets.

From: Machine learning-based prediction model for myocardial ischemia under high altitude exposure: a cohort study

 

Training dataset

Test dataset

No

Yes

OR

P

No

Yes

OR

P

N = 1964

N = 177

(95% CI)

N = 656

N = 58

(95% CI)

Age (y)

23.0 [22.0; 26.0]

24.0 [22.0; 29.0]

1.07 [1.04; 1.10]

0.001

24.0 [22.0; 27.0]

24.0 [22.0; 27.8]

1.03 [0.97; 1.09]

0.313

Sex:

   

0.005

   

1.000

 Female

26 (1.32%)

8 (4.52%)

3.57 [1.48; 7.72]

–

11 (1.68%)

0 (0.00%)

 

–

 Male

1938 (98.7%)

169 (95.5%)

Ref

–

645 (98.3%)

58 (100%)

 

–

Smoking duration

   

0.012

   

0.274

 None

1073 (54.6%)

92 (52.0%)

Ref

–

384 (58.5%)

28 (48.3%)

Ref

–

  < 10 years

779 (39.7%)

65 (36.7%)

0.97 [0.70; 1.35]

–

218 (33.2%)

25 (43.1%)

1.57 [0.89; 2.77]

–

  ≥ 10 years

112 (5.70%)

20 (11.3%)

2.09 [1.21; 3.46]

–

54 (8.23%)

5 (8.62%)

1.30 [0.42; 3.27]

–

Chesttightness.or.Chestpain

   

0.002

   

0.268

 No

1867 (95.1%)

158 (89.3%)

Ref

–

614 (93.6%)

52 (89.7%)

Ref

–

 Yes

97 (4.94%)

19 (10.7%)

2.33 [1.35; 3.83]

–

42 (6.40%)

6 (10.3%)

1.72 [0.62; 3.98]

–

BMI (kg/m2)

22.1 [20.8; 23.6]

22.6 [21.0; 24.4]

1.09 [1.02; 1.16]

0.023

22.2 [20.8; 23.8]

22.5 [20.7; 23.7]

1.02 [0.90; 1.15]

0.680

SBP (mmHg)

116 [110; 120]

118 [110; 124]

1.00 [1.00; 1.01]

0.018

118 [110; 121]

120 [110; 130]

1.04 [1.02; 1.07]

0.006

DBP (mmHg)

80.0 [73.0; 84.0]

80.0 [75.0; 85.0]

1.01 [0.99; 1.03]

0.436

80.0 [73.0; 84.0]

81.5 [77.0; 88.0]

1.05 [1.02; 1.08]

0.002

HR (min−1)

80.0 [71.0; 89.0]

80.0 [75.0; 88.0]

1.00 [0.99; 1.02]

0.537

79.0 [70.0; 88.0]

78.5 [69.0; 85.8]

0.99 [0.97; 1.01]

0.486

OS (%)

93.0 [92.0; 95.0]

93.0 [92.0; 96.0]

1.01 [0.97; 1.04]

0.159

93.0 [92.0; 95.0]

93.0 [92.0; 95.0]

1.00 [0.99; 1.01]

0.132

Highland acclimatization training*

   

0.986

   

1.000

 No

151 (7.69%)

13 (7.34%)

Ref

–

37 (5.64%)

3 (5.17%)

Ref

–

 Yes

1813 (92.3%)

164 (92.7%)

1.04 [0.60; 1.97]

–

619 (94.4%)

55 (94.8%)

1.05 [0.36; 4.61]

–

Altitude of original station (m)

   

0.002

   

0.202

  < 1500

1830 (93.2%)

152 (85.9%)

Ref

–

593 (90.4%)

50 (86.2%)

Ref

–

 1500 –2500

114 (5.80%)

23 (13.0%)

2.44 [1.48; 3.87]

–

51 (7.77%)

8 (13.8%)

 

–

  > 2500

20 (1.02%)

2 (1.13%)

1.29 [0.19; 4.49]

–

12 (1.83%)

0 (0.00%)

 

–

3 km test in Non-High Altitude (Score)#

77.0 [65.0; 91.0]

82.0 [62.0; 93.0]

1.00 [0.99; 1.00]

0.414

77.0 [65.0; 91.0]

81.0 [0.00; 90.0]

1.00 [0.99; 1.00]

0.944

Sit-ups in Non-High Altitude (Score)#

93.0 [85.0; 101]

95.0 [88.0; 101]

1.01 [1.00; 1.02]

0.173

93.0 [85.0; 101]

93.0 [86.2; 101]

1.00 [0.98; 1.02]

0.814

Serpentine Run in Non-High Altitude (Score)#

90.0 [75.0; 96.0]

90.0 [78.0; 96.0]

1.00 [0.99; 1.01]

0.923

90.0 [75.0; 96.0]

83.0 [72.5; 95.0]

0.99 [0.98; 1.00]

0.195

SCOPA-AUT SCORE in non-high altitude

4.00 [2.00; 8.00]

3.00 [2.00; 7.00]

0.98 [0.95; 1.02]

0.170

4.00 [2.00; 8.00]

5.00 [3.00; 8.00]

1.03 [0.97; 1.10]

0.121

Ca (mmol/L)

2.37 [2.31; 2.41]

2.42 [2.32; 2.47]

2.23 [1.88; 3.63]

 < 0.001

2.37 [2.30; 2.41]

2.38 [2.31; 2.47]

1.75 [1.04; 2.32]

0.036

Crea (μmol/L)

88.0 [80.0; 97.0]

83.0 [79.0; 93.0]

0.97 [0.95; 0.98]

 < 0.001

89.0 [81.0; 97.0]

85.5 [79.0; 95.0]

0.98 [0.95; 1.01]

0.100

GLU (mmol/L)

4.03 [3.53; 4.47]

4.33 [4.10; 4.59]

2.11 [1.73; 2.58]

 < 0.001

 < 0.001

4.03 [3.53; 4.47]

4.33 [3.99; 4.59]

1.92 [1.37; 2.67]

Eos.Per (%)

2.20 [1.60; 3.00]

2.60 [1.30; 5.00]

1.28 [1.20; 1.36]

 < 0.001

2.20 [1.50; 3.00]

2.00 [1.10; 4.92]

1.23 [1.10; 1.36]

0.608

G (g/L)

25.6 [23.6; 27.3]

27.8 [25.6; 28.5]

1.22 [1.16; 1.29]

 < 0.001

25.6 [22.9; 27.3]

27.8 [25.9; 28.5]

1.20 [1.11; 1.30]

 < 0.001

MCHC (g/L)

338 (9.00)

332 (24.5)

0.95 [0.94; 0.97]

0.001

338 (9.25)

335 (10.1)

0.97 [0.94; 1.00]

0.034

P (mmol/L)

1.19 [1.08; 1.27]

1.09 [1.05; 1.14]

0.11 [0.04; 0.31]

 < 0.001

1.17 [1.07; 1.25]

1.10 [1.06; 1.14]

0.08 [0.01; 0.47]

0.001

PLT (× 109/L)

230 (37.5)

214 (45.3)

0.99 [0.99; 0.99]

 < 0.001

230 (37.7)

211 (49.6)

0.99 [0.98; 0.99]

0.005

AST (U/L)

22.0 [19.0; 30.0]

20.0 [18.0; 26.0]

0.98 [0.96; 0.99]

 < 0.001

22.0 [19.0; 29.0]

19.0 [17.0; 24.0]

0.95 [0.92; 0.99]

 < 0.001

TP (g/L)

72.0 [70.7; 74.6]

73.7 [70.7; 75.5]

1.11 [1.06; 1.16]

 < 0.001

71.5 [69.9; 74.6]

74.1 [70.9; 75.6]

1.11 [1.03; 1.19]

0.014

Urea (mmol/L)

5.10 [4.40; 5.70]

5.50 [5.00; 6.30]

1.35 [1.18; 1.53]

 < 0.001

5.10 [4.60; 5.60]

5.90 [5.03; 7.22]

1.65 [1.32; 2.06]

 < 0.001

WBC (× 109/L)

6.75 [5.84; 7.36]

5.91 [5.29; 7.26]

0.74 [0.65; 0.85]

 < 0.001

6.59 [5.70; 7.36]

5.90 [5.51; 6.86]

0.90 [0.72; 1.13]

0.022

  1. Continuous data conforming to a normal distribution were reported as mean (SD) and those not conforming as median (quartiles). Odds ratios and 95% CIs were calculated, either using count data for categorical variables or a logistic regression model for continuous variables. Statistical significance was determined using t-test, Rank-sum test or χ2 test, with p-values calculated.
  2. Non-High Altitude: an altitude < 2500 m. High Altitude: an altitude ≥ 2500 m. BMI body mass index, SBP systolic blood pressure, DBP diastolic blood pressure, HR heart rate, OS oxygen saturation, SCOPA-AUT the Scale for Outcomes in Parkinson′s Disease for Autonomic Symptoms, Ca calcium, Crea creatinine, Eos.Per eosinophils percentage, G globulin, GLU glucose, MCHC mean corpuscular hemoglobin concentration, P phosphorus, PLT platelet, AST aspartate aminotransferase, TP total protein, UA uric acid, WBC white blood cell.
  3. *Participants entered the destination after 1 month of highland acclimatization training at an altitude of 3000 m.
  4. #The calculation of physical ability scores was based on Military Common Subject Training Program.
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