Table 3 Subgroup analysis of postoperative delirium after head and neck surgery

Pooled results

 Subgroup analyses based on region

  Asia

12

0.18 (0.13–0.22)

93.0

  Western countries

4

0.26 (0.19–0.33)

75.4

 Subgroup analyses based on criteria for POD

  DSM-IV

8

0.20 (0.13–0.27)

95.0

  DSM-V

4

0.16 (0.10–0.22)

81.8

  CAM

2

0.20 (0.02–0.41)

95.0

  Others

2

0.27 (0.15–0.39)

80.4

 Subgroup analyses based on number of sample

  N <200

10

0.23 (0.17–0.29)

87.9

  N ≥ 200

6

0.15 (0.08–0.21)

95.1

 Subgroup analyses based on quality of included studies

  NOS 9

7

0.19 (0.13–0.24)

84.4

  NOS 7–8

9

0.20 (0.15–0.24)

95.1

 Subgroup analyses based on study design

  Retrospective

14

0.20 (0.15–0.25)

93.5

  Others

2

0.20 (0.02–0.41)

95.0