Table 1 Demographics among patients with hemoglobin ≤ 6.5 mmol/L on the 3rd postoperative day

 Female

28 (53.8)

20 (52.6)

41 (51.2)

18 (45.0)

107 (51.0)

 Male

24 (46.2)

18 (47.4)

39 (48.8)

22 (55.0)

103 (49.0)

0.853

Age

82.6 (9.1)

83.2 (7.1)

83.6 (8.9)

84.7 (9.2)

83.5 (8.7)

0.709

BMI (kg/m²)

24.1 (4.2)

24 (5.1)

24.2 (3.9)

23.2 (3.8)

23.9 (4.2)

0.655

Charlson Comorbidity Index

1.9 (2)

2.7 (2.1)

1.9 (2.2)

2.1 (1.7)

2.1 (2.1)

0.219

Polypharmacy (≥5 medications)

34 (65.4)

33 (86.8)

55 (68.8)

34 (85.0)

156 (74.3)

0.023*

 Home-independent

38 (73.1)

27 (71.1)

55 (68.8)

29 (72.5)

149 (71.0)

 Nursing home

14 (26.9)

11 (28.9)

25 (31.2)

11 (27.5)

61 (29.0)

0.951

 1

51 (98.1)

37 (97.4)

12 (15.0)

7 (17.5)

107 (51.0)

 2

1 (1.9)

1 (2.6)

68 (85.0)

33 (82.5)

103 (49.0)

< 0.001*

 Intracapsular

29 (55.8)

14 (36.8)

31 (38.8)

13 (32.5)

87 (41.4)

 Extracapsular

23 (44.2)

24 (63.2)

49 (61.2)

27 (67.5)

123 (58.6)

0.098

 Arthroplasty

19 (36.5)

16 (42.1)

23 (28.8)

7 (17.5)

65 (31.0)

 Intramedullary nails

19 (36.5)

21 (55.3)

48 (60.0)

30 (75.0)

118 (56.2)

 AO screws

2 (3.8)

0 (0.0)

3 (3.8)

1 (2.5)

6 (2.9)

 Dynamic hip screws

7 (13.5)

1 (2.6)

4 (5.0)

1 (2.5)

13 (6.2)

 Other

5 (9.6)

0 (0.0)

2 (2.5)

1 (2.5)

8 (3.8)

0.014*

Time to theatre (days)

0.6 (0.5)

0.8 (0.8)

0.8 (0.5)

0.7 (0.6)

0.7 (0.6)

0.425

Preoperative Hgb (mmol/L)

7.7 (0.8)

7.4 (1)

7.9 (0.7)

6.8 (1)

7.5 (0.9)

< 0.001*

 Missing

9

5

19

10

43

Perioperative blood loss (mL)

185.7 (108.9)

387.1 (414.1)

205.1 (159.9)

254.7 (196.1)

246.8 (241.1)

0.001*

 Missing

17

7

21

8

53

Hgb postoperative day 1 (mmol/L)

6.3 (0.6)

5.4 (0.8)

6.1 (0.6)

5.1 (0.6)

5.8 (0.8)

< 0.001*

 Missing

2

0

0

0

2

Hgb postoperative day 3 (mmol/L)

5.8 (0.5)

5.4 (0.7)

5.6 (0.5)

5.2 (0.7)

5.6 (0.6)

< 0.001*

Hgb postoperative between day

14–30 (mmol/L)

6.3 (0.7)

6.4 (0.5)

6.8 (0.6)

6.6 (0.8)

6.6 (0.7)

0.116

 Missing because deceased

5

4

2

4

15

 Missing because no hgb control

28

21

48

12

109

Length of stay (days)

6.5 (3.9)

7.1 (4)

5.9 (2.1)

6.9 (2.6)

6.5 (3.1)

0.177

 Home-independent

18 (34.6)

14 (36.8)

37 (46.2)

14 (35.0)

83 (39.5)

 Nursing home

34 (65.4)

20 (52.6)

43 (53.8)

24 (60.0)

121 (57.6)

 Dead in hospital

0 (0.0)

4 (10.5)

0 (0.0)

2 (5.0)

6 (2.9)

0.023*

 Readmitted

13 (25.0)

5 (13.2)

14 (17.5)

10 (25.0)

42 (20.0)

 Transmitted to ICU^a

0 (0.0)

0 (0.0)

1 (1.2)

1 (2.5)

2 (1.0)

0.558