Table 6 Bivariate and multivariable Cox proportional hazard regression analysis of traumatic brain injury patients admitted to East Amhara comprehensive Specialized hospitals from 1st January 2016 to 31st December 2021(n = 429)

Mode of admission

Direct admission

25

51

1

1

Referral

120

233

1.54(0.97–2.44)

0.76(0.54–1.52)

0.082

Blood transfusion

Yes

32

47

1

1

No

113

237

1.38(1.02–2.41)

2.12(1.62–3.96)

0.054

Types of injury

Closed

79

51

1

1

Opened

66

233

0.24(0.170.33)

0.25(0.18–0.36)

0.001*

Presence of co-existing injuries

Yes

125

204

1

1

No

20

80

0.33(0.20–0.53)

0.40(0.24–0.66)

0.001*

ICU admission

Yes

62

64

1

1

No

83

220

0.35(0.25–0.49)

0.42(0.29–0.60)

0.002*

Pulmonary edema

Yes

29

35

1

1

No

116

249

0.56(0.31–0.87)

0.68(0.45–1.12)

0.172

Serum sodium level

< 135

11

10

1

1

135–145

57

207

2.56(1.33–3.49)

1.82(1.19–2.45)

0.064

> 145

77

67

2.78(2.04–3.65)

3.13(2.65–4.41)

0.102

Times of arrival

within 4 h

15

127

1

1

4–24 h

101

145

4.07(2.36–7.02)

3.48(2.01–6.03)

0.001*

> 24 h

29

12

9.72(5.18–16.29)

6.69(3.49–12.28)

0.001*

Severity of TBI

Severe

75

76

1

1

Moderate

61

167

0.37(0.26–0.52)

0.56(0.21–0.89)

0.002*

Mild

9

41

0.22(0.10–0.45)

0.43(0.29–0.56)

0.032*

Aspiration pneumonia

Yes

50

39

1

1

No

95

245

0.47(0.21–0.72)

0.82(0.64–1.25)

0.071

Serum albumin

< 3.5 g/dl

56

70

1

1

≥ 3.5 g/dl

89

214

0.32(0.22–0.45)

0.66(0.49–0.94)

0.012*

Elevation

Yes

46

104

1

1

No

42

34

3.43(1.49–5.97)

4.25(2.78–6.78)

0.828

Subdural hematoma

No

108

249

1

1

Yes

37

35

3.88(2.63–5.74)

2.72(1.77–4.19)

0.001*