Table 1 Demographic characteristics and risk factors associated with pre-admission DVT

Age (mean years±SD)

78.68 ± 7.89

78.49 ± 8.00

79.38 ± 7.44

0.199

Gender (Male/Female)

0.07

 Male

273 (34.6%)

226 (36.2%)

47 (28.7%)

 Female

515 (65.4%)

398 (63.8%)

117 (71.3%)

BMI (kg/m2)

0.005*

  < 30

756 (95.9%)

605 (97.0%)

151 (92.1%)

  > 30

32 (4.1%)

19 (3.0%)

13 (7.9%)

Injury side (left/right)

0.327

 Left

416 (52.8%)

335 (53.7%)

81 (49.4%)

 Right

372 (47.2%)

289 (46.3%)

83 (50.6%)

Injury mechanism

0.002*

 Low energy trauma

716 (90.9%)

577 (92.5%)

139 (84.8%)

 High energy trauma

72 (9.1%)

47 (7.5%)

25 (15.2%)

Time from injury to admission (days)

2.10 ± 1.79

1.87 ± 1.59

2.96 ± 2.22

< 0.001†

Hemoglobin(g/L)

113.92 ± 19.09

115.45 ± 18.93

108.13 ± 18.62

< 0.001†

 Hypertension

440 (55.8%)

350 (56.1%)

90 (54.9%)

0.781

 Diabetes

238 (30.2%)

171 (27.4%)

67 (40.9%)

0.001*

 COPD

87 (11.0%)

54 (8.7%)

33 (20.1%)

< 0.001*

 Atrial fibrillation

60 (7.6%)

34 (5.4%)

26 (15.9%)

< 0.001*

 Coronary heart disease

162 (20.6%)

121 (19.4%)

41 (25.0%)

0.114

 Cerebrovascular accident

172 (21.8%)

128 (20.5%)

44 (26.8%)

0.081

 Cancer

78 (9.9%)

65 (10.4%)

13 (7.9%)

0.342

 Dementia

35 (4.4%)

21 (3.4%)

14 (8.5%)

0.004*

 Liver and kidney disease

43 (5.5%)

35 (5.6%)

8 (4.9%)

0.714

 Thyroid disease

27 (3.4%)

18 (2.9%)

9 (5.5%)

0.103

 Varicose veins

46 (5.8%)

29 (4.7%)

17 (10.4%)

0.005*

Age-adjusted CCI

4.27 ± 1.44

4.17 ± 1.42

4.63 ± 1.44

< 0.001†

ASA class

0.001*

 1

26 (3.3%)

24 (3.8%)

2 (1.2%)

 2

576 (73.1%)

470 (75.3%)

106 (64.6%)

 3

180 (22.8%)

127 (20.4%)

53 (32.3%)

 4

6 (0.8%)

3 (0.5%)

3 (1.8%)

AO classification

0.008*

 A1

174 (22.1%)

145 (23.2%)

29 (17.7%)

 A2

522 (66.2%)

417 (66.8%)

105 (64.0%)

 A3

92 (11.7%)

62 (9.9%)

30 (18.3%)