Table 3 Comparisons of sleep characteristics and health-related quality of life between ISI < 8 group and ISI ≥ 8 group

N

107

43

Third grade/Fourth grade

45/62

17/26

0.86

PSQI, median (IQR)

5.0 (3.0–6.0)

8.0 (6.0–9.0)

 < 0.001

 PSQI ≥ 6, N (%)

39 (36.4)

33 (76.7)

 < 0.001

Evening Chronotype, N (%)

68 (63.6)

32 (74.4)

0.25

ISI, median (IQR)

3.0 (2.0–5.0)

10.0 (9.0–12.0)

 < 0.001

 Difficulty initiating sleep, N (%)

5 (4.7)

19 (44.2)

 < 0.001

 Difficulty maintaining sleep, N (%)

0 (0.0)

6 (14.0)

 < 0.001

 Early waking, N (%)

2 (1.9)

4 (9.3)

0.06

Weekday TST hr, median (IQR)

6.33 (5.50–7.25)

6.33 (5.50–7.12)

0.66

 < 6 h, N (%)

42 (39.3)

16 (37.2)

0.95

 6–7 h, N (%)

27 (25.2)

12 (27.9)

 ≥ 7 h, N (%)

38 (35.5)

15 (34.9)

Weekend TST hr, median (IQR)

8.00 (7.00–9.00)

8.00 (7.00–8.67)

0.38

 < 6 h, N (%)

9 (8.4)

3 (7.0)

0.85

 6–7 h, N (%)

14 (13.1)

7 (16.3)

 ≥ 7 h, N (%)

84 (78.5)

33 (76.7)

Catch-up on sleep, median (IQR)

1.50 (0.50–2.88)

1.00 (0.42–2.54)

0.56

 ≥ 2 h, N (%)

46 (43.0)

14 (32.6)

0.27

SF8

 Physical functioning, median (IQR)

54.3 (54.3–54.3)

54.3 (48.7–54.3)

0.01

 Role physical, median (IQR)

54.9 (47.8–54.9)

47.8 (43.6–54.9)

 < 0.001

 Bodily pain, median (IQR)

59.1 (51.3–59.1)

59.1 (51.3–59.1)

0.74

 General health, median (IQR)

52.7 (52.7–60.0)

52.7 (43.0–52.7)

0.02

 Vitality, median (IQR)

55.5 (47.4–55.5)

47.4 (47.4–55.5)

 < 0.001

 Social functioning, median (IQR)

55.2 (47.3–55.2)

47.3 (41.4–55.2)

 < 0.001

 Role emotional, median (IQR)

49.0 (49.0–55.2)

43.7 (43.7–49.0)

 < 0.001

 Mental health, median (IQR)

51.2 (45.1–56.7)

45.1 (38.3–45.1)

 < 0.001

 PCS, median (IQR)

53.8 (51.0–55.5)

53.6 (50.5–56.6)

0.98

 MCS, median (IQR)

50.1 (46.2–54.5)

43.4 (37.6–47.6)

 < 0.001