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Table 1 Characteristics of study population

From: A nomogram to distinguish noncardiac chest pain based on cardiopulmonary exercise testing in cardiology clinic

Characteristic

Total

(N = 1,531)

Training dataset

(N = 918)

Testing dataset

(N = 613)

P-value

Age (years)

57.5 ± 12.5

57.3 ± 12.8

57.7 ± 12.0

0.543

Female Sex

440 (28.7%)

264 (28.8%)

176 (28.7%)

1

BMI

24.1 ± 3.26

24.2 ± 3.30

24.1 ± 3.20

0.804

Hypertension

621 (40.6%)

366 (39.9%)

255 (41.6%)

0.534

Diabetes

284 (18.6%)

181 (19.7%)

103 (16.8%)

0.171

Diagnosis

   

0.555

 CAD

1,206 (78.8%)

718 (78.2%)

488 (79.6%)

 

 Anxiety/Depression

325 (21.2%)

200 (21.8%)

125 (20.4%)

 

Exercise time (minute)

447 ± 118

445 ± 115

450 ± 122

0.417

Maximum load (W)

100 ± 39.0

100 ± 38.4

101 ± 40.0

0.811

RPE

16.1 ± 1.77

16.2 ± 1.77

16.0 ± 1.75

0.085

RER

1.22 ± 0.143

1.22 ± 0.145

1.22 ± 0.139

0.901

*Peak VO2 (mL/min)

1,290 ± 419

1,290 ± 407

1,300 ± 436

0.620

*PeakVO2/kg (mL/kg/min)

19.5 ± 5.53

19.5 ± 5.37

19.6 ± 5.75

0.588

PeakVO2%pred (%)

71.0 ± 18.8

70.8 ± 18.6

71.5 ± 19.3

0.460

HRrest (beat)

76.3 ± 14.0

76.4 ± 14.3

76.1 ± 13.5

0.652

HRpeak (beat)

134 ± 23.5

135 ± 23.7

134 ± 23.3

0.713

HR slope (beat/s)

0.133 ± 0.0465

0.133 ± 0.0432

0.134 ± 0.0512

0.724

Abnormal HRrest

727 (47.5%)

426 (46.4%)

301 (49.1%)

0.325

Abnormal HR reaction

1,409 (92.0%)

855 (93.1%)

554 (90.4%)

0.063

SBPrest (mmHg)

128 ± 19.9

128 ± 20.1

128 ± 19.7

0.934

DBPrest (mmHg)

77.4 ± 11.5

77.1 ± 11.2

77.8 ± 12.0

0.295

SBPpeak (mmHg)

177 ± 31.7

177 ± 31.4

177 ± 32.2

0.996

DBPpeak (mmHg)

87.3 ± 16.0

87.2 ± 15.6

87.6 ± 16.6

0.638

Abnormal DBP reaction

1,159 (75.7%)

703 (76.6%)

456 (74.4%)

0.385

Abnormal SBP reaction

957 (65.5%)

575 (62.6%)

382 (62.3%)

0.942

O2pulse (mL/beat)

10.2 ± 19.4

9.69 ± 2.81

11.0 ± 30.4

0.304

O2pulse%pred (%)

84.3 ± 21.8

84.1 ± 21.6

84.5 ± 22.0

0.691

ΔVO2/ΔWR

9.39 ± 2.26

9.46 ± 2.23

9.29 ± 2.29

0.148

AT VE/VCO2

30.5 ± 5.18

30.3 ± 4.99

30.8 ± 5.44

0.063

VE/VCO2 slope

29.2 ± 6.37

29.1 ± 6.19

29.4 ± 6.62

0.321

Abnormal HRR

305 (19.9%)

181 (19.7%)

124 (20.2%)

0.857

Decreased exercise tolerance

1,092 (71.3%)

667 (72.7%)

425 (69.3%)

0.176

Cardiac classification

   

0.973

 A

719 (47.0%)

432 (47.1%)

287 (46.8%)

 

 B

515 (33.6%)

311 (33.9%)

204 (33.3%)

 

 C

262 (17.1%)

155 (16.9%)

107 (17.5%)

 

 D

35 (2.3%)

20 (2.2%)

15 (2.4%)

 
  1. Continuous variables are shown as mean ± standard deviation. Discrete variables are presented as n(%)
  2. RPE: rating of perceived exertion; RER: respiratory exchange ratio, the value of VCO2/VO2 at peak exercise; Peak VO2%pred: percent predicted VO2, calculated as actual peak VO2/predicted VO2 estimated by sex, age, and weight; HRrest: resting heart rate; HRpeak: peak heart rate; HR slope: the ratio between change in HR from rest to peak exercise and exercise time; Abnormal HR reaction: HRpeak-HRrest<89; SBPrest, resting systolic blood pressure; DBPrest, resting diastolic blood pressure; DBPpeak, peak diastolic blood pressure; Abnormal DBP reaction: DBPpeak-DBPrest ≤ 0; Abnormal SBP reaction: the SBP elevation was less than 7 times the Mets; O2 pulse: peak VO2 (mL/min) divided by peak HR; O2pulse%pred: percent predicted O2 pulse; ΔVO2/ΔWR: the linear relationship of oxygen consumption and work rate; AT VE/VCO2: minute ventilation (VE)/carbon dioxide production (VCO2) in the anaerobic threshold (AT); VE/VCO2 slope: the linear relationship of VE and VCO2; Abnormal HRR: heart rate recovery in 1 min ≤ 12; Decreased exercise tolerance: peak VO2%pred<80; Cardiac classification: according to Weber KT criterion, A:Peak VO2/kg>20 or AT VO2>14, B:16 ≤ Peak VO2/kg ≤ 20 or 11 ≤ AT VO2 ≤ 14, C:10 ≤ Peak VO2/kg<16 or 8 ≤ AT VO2<11, D: Peak VO2/kg<10 or AT VO2<8;
  3. *Peak VO2 was presented in both absolute (ml/min) and relative terms (mL/kg/min);
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BMC Medical Informatics and Decision Making

ISSN: 1472-6947

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