Table 5 Associations of BMI, NC and LOS with the ESS and weighted ESS scores (Mean ± SD. Derivation cohort, n = 756; validation cohort, n = 810)

 0–10

25.50 ± 4.35

25.53 ± 4.19

37.09 ± 3.14

37.19 ± 3.07

83.28 ± 8.61

79.62 ± 8.68

 11–12

26.48 ± 4.50

26.00 ± 4.12

37.76 ± 2.91

38.15 ± 3.37

78.49 ± 9.91

76.65 ± 10.13

 13–15

25.99 ± 3.04

26.82 ± 6.51

38.69 ± 2.25

37.89 ± 4.03

77.31 ± 7.46

76.44 ± 8.17

 16–24

27.94 ± 3.73

28.49 ± 4.81

39.17 ± 2.63

38.88 ± 3.68

72.55 ± 11.05

72.95 ± 9.94

F value

13.161

17.837

22.338

11.347

51.503

23.957

p value

<  0.001

<  0.001

<  0.001

<  0.001

<  0.001

<  0.001

r_s value

0.259

0.248

0.283

0.193

−0.452

−0.294

p value

<  0.001

<  0.001

<  0.001

<  0.001

<  0.001

<  0.001

 0–14

25.01 ± 5.00

24.91 ± 3.97

35.84 ± 3.38

36.56 ± 3.01

88.48 ± 4.93

81.33 ± 8.48

 15–19

25.27 ± 3.82

26.15 ± 4.64

37.52 ± 2.81

37.60 ± 2.91

82.00 ± 7.13

79.05 ± 8.13

 20–29

26.57 ± 3.92

26.38 ± 5.12

38.19 ± 2.72

38.15 ± 3.57

77.76 ± 9.74

77.55 ± 9.39

 30–40

27.66 ± 3.82

27.73 ± 4.85

39.16 ± 2.51

38.43 ± 3.61

72.58 ± 10.43

73.33 ± 9.36

F value

15.572

13.235

36.825

12.762

92.166

30.979

p value

<  0.001

<  0.001

<  0.001

<  0.001

<  0.001

<  0.001

r_s value

0.279

0.244

0.337

0.214

− 0.565

−0.351

p value

<  0.001

<  0.001

<  0.001

<  0.001

<  0.001

<  0.001