Table 1 Basic characteristics of patients among two groups

Age (year, \(\overline x\) ± s)

64.19 ± 10.51

63.34 ± 10.38

0.414

Sex, n (%)

0.834

  Male, n (%)

106(54.08%)

113(55.12%)

  Female, n (%)

90(45.92%)

92(44.88%)

Height (cm, \(\overline x\) ± s)

165.47 ± 7.81

165.78 ± 7.54

0.695

Body weight (kg, \(\overline x\) ± s)

66.95 ± 11.67

68.13 ± 11.43

0.309

ASA grade, n (%)

0.604

  I, n (%)

  II, n (%)

11(5.61%)

156(79.59%)

11(5.37%)

156(76.10%)

  III, n (%)

29(14.80%)

38(18.54%)

Hypertension n, (%)

90(45.92%)

93(45.37%)

0.912

Diabetes n, (%)

53(27.04%)

52(25.37%)

0.703

Coronary heart disease n, (%)

50(25.51%)

43(20.98%)

0.282

Drinking history n, (%)

90(45.92%)

94(45.85%)

0.990

Smoking history n, (%)

72(36.73%)

81(39.51%)

0.567

Preoperative Hb (g/L, x ± s)

127.81 ± 20.72

127.29 ± 20.98

0.802

Preoperative albumin (g/L, \(\overline x\) ± s)

37.88 ± 4.04

37.84 ± 4.17

0.915

Years of education n, (%)

0.143

  0 n, (%)

10(5.10%)

15(7.32%)

  1 to 6 n, (%)

52(26.53%)

50(24.39%)

  7 to 9 n, (%)

73(37.24%)

84(40.98%)

  10 to 12 n, (%)

56(28.57%)

43(20.98%)

  > 12 n, (%)

5(2.55%)

13(6.34%)

Preoperative MMSE score (point, \(\overline x\) ± s)

26.66 ± 1.34

26.72 ± 1.42

0.644

Preoperative PSQI score (point, \(\overline x\) ± s)

7.43 ± 3.56

7.44 ± 3.58

0.966