Table 3 Subgroup analysis for the association between different levels of troponin-I (all compared to Group I as a reference) and hospital mortality. The following variables were used as covariates in the model: age, APACHE II, sex, admission diagnosis, diabetes, chronic liver disease, chronic respiratory disease, chronic renal diseases, chronic immunosuppression, vasopressor use, sepsis, cardiac arrest, acute kidney injury, Glasgow Coma Scale, platelet, INR, bilirubin and lactic acid levels) Interaction test was performed for each subgroup

 < 50

1.72 (1.06, 2.78)

0.03

0.02

2.86 (1.68, 4.85)

0.0001

0.03

4.71 (2.55, 8.72)

<0.0001

0.0005

 ≥ 50

0.87 (0.64,1.17)

0.34

1.28 (0.91,1.80)

0.16

1.20 (0.82,1.77)

0.35

 Male

0.99 (0.72,1.35)

0.95

0.50

1.68 (1.18, 2.39)

0.004

0.82

1.64 (1.10, 2.44)

0.02

0.63

 Female

1.23 (0.82,1.86)

0.32

1.59 (1.00, 2.53)

0.05

2.16 (1.22, 3.81)

0.008

 Yes

1.07 (0.66,1.74)

0.78

0.77

1.73 (1, 2.99)

0.05

0.95

1.69 (0.90, 3.17)

0.10

0.74

 No

1.11 (0.83, 1.49)

0.47

1.68 (1.21, 2.33)

0.002

1.85 (1.26, 2.72)

0.002

 Yes

0.81 (0.55, 1.19)

0.28

0.24

0.97(0.64,1.47)

0.88

0.008

0.94 (0.59,1.49)

0.78

0.002

 No

1.22 (0.87, 1.71)

0.24

2.39 (1.62, 3.53)

<0.0001

3.23 (1.97, 5.28)

<0.0001

 Non-operative

1.02 (0.77, 1.35)

0.91

0.53

1.48 (1.07, 2.03)

0.02

0.29

1.5 (1.03, 2.17)

0.03

0.07

 Post-operative

1.47 (0.85, 2.55)

0.17

2.74 (1.48, 5.07)

0.001

3.29 (1.62, 6.71)

0.001

 Yes

0.79 (0.38, 1.64)

0.53

0.37

1.23 (0.51, 2.97)

0.65

0.52

3.19 (0.84,12.16)

0.09

0.4584

 No

1.13 (0.87, 1.48)

0.36

1.74 (1.29, 2.34)

0.0003

1.82 (1.29, 2.56)

0.0006

 Yes

1.24 (0.71, 2.18)

0.45

0.63

2.29 (1.23, 4.26)

0.009

0.30

1.38 (0.73, 2.63)

0.32

0.23

 No

1.04 (0.79,1.37)

0.79

1.52 (1.11, 2.09)

0.01

2.11 (1.43, 3.12)

0.0002

 Yes

0.76 (0.41, 1.42)

0.39

0.53

1.29 (0.65, 2.56)

0.47

0.64

1.2 (0.49, 2.95)

0.69

0.55

 No

1.13 (0.86, 1.48)

0.39

1.70 (1.25, 2.32)

0.0007

1.85 (1.30, 2.63)

0.0006

 Yes

0.98 (0.44, 2.18)

0.96

0.94

2.27 (0.95, 5.42)

0.07

0.33

1.37 (0.55, 3.42)

0.50

0.45

 No

1.09 (0.84, 1.41)

0.52

1.52 (1.13, 2.05)

0.006

1.94 (1.36, 2.75)

0.0002

 Yes

0.85 (0.45, 1.60)

0.61

0.19

1.49 (0.68, 3.28)

0.32

0.36

1.36 (0.49, 3.74)

0.55

0.37

 No

1.11 (0.85, 1.46)

0.43

1.68 (1.24, 2.28)

0.0007

1.87 (1.32, 2.64)

0.0005

 Yes

0.94 (0.63, 1.42)

0.77

0.76

1.05 (0.66,1.66)

0.84

0.05

1.05 (0.64,1.73)

0.84

0.01

 No

1.1 (0.8,1.50)

0.57

2.12 (1.49, 3.02)

<0.0001

2.80 (1.79, 4.38)

<0.0001

 Yes

1.02 (0.49, 2.12)

0.97

0.97

1.17 (0.54, 2.52)

0.70

0.23

1.27 (0.55, 2.95)

0.5811

0.33

 No

1.08 (0.82,1.4)

0.59

1.8 (1.33, 2.44 )

0.0002

1.92 (1.34, 2.76)

0.0004

 Yes

1.08 (0.74,1.58)

0.70

0.64

1.4 (0.91, 2.15)

0.13

0.57

1.37 (0.85, 2.2)

0.20

0.15

 No

1.01 (0.73,1.4)

0.96

1.79 (1.24, 2.59)

0.002

2.23 (1.41, 3.51)

0.0006

 Yes

4.21 (0.68, 26.19)

0.12

0.23

4.92 (0.79, 30.77)

0.09

0.50

6.48 (1.02, 41.23)

0.05

0.43

 No

1.03 (0.80, 1.33)

0.81

1.62 (1.21, 2.16)

0.001

1.74 (1.23, 2.46)

0.002