Authors | Question/objective sufficiently described? | Study design evident and appropriate? | Method of subject/comparison group selection or source of information/input variables described and appropriate? | Subject (and comparison group, if applicable) characteristics sufficiently described? | If interventional and random allocation was possible, was it described? | If interventional and blinding of investigators was possible, was it reported? | If interventional and blinding of subjects was possible, was it reported? | Outcome and (if applicable) exposure measure(s) well defined and robust to measurement/misclassification bias? Means of assessment reported? | Sample size appropriate? | Analytical methods described/justified and appropriate? | Some estimate of variance is reported for the main results? | Controlled for confounding? | Results reported in sufficient detail? | Conclusions supported by the results? | Summary score | ||

An et al
21
| 2 | 2 | 2 | 1 | N/A | N/A | N/A | 2 | 2 | 1 | 1 | 2 | 2 | 2 | 0.86 | Yes | 2 |

Bükki et al
22
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 2 | 1 | 2 | 2 | 0 | 2 | 2 | 0.86 | Partial | 1 |

Davies et al
23
| 2 | 2 | 2 | 1 | N/A | N/A | N/A | 2 | 1 | 2 | 2 | 1 | 1 | 2 | 0.82 | No | 0 |

Engelberg et al
24
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 2 | 1 | 2 | 1 | 1 | 2 | 2 | 0.86 | N/A | |

Gao et al
25
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 2 | 1 | 2 | 1 | 2 | 2 | 2 | 0.91 | ||

Hauke et al
26
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 2 | 1 | 1 | 0 | 1 | 2 | 2 | 0.77 | ||

Heyland et al
27
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 2 | 2 | 2 | 1 | 1 | 2 | 2 | 0.91 | ||

Heyland et al
28
| 2 | 2 | 2 | 1 | N/A | N/A | N/A | 2 | 1 | 2 | 2 | 0 | 2 | 0 | 0.73 | ||

Hwang et al
29
| 1 | 2 | 2 | 2 | N/A | N/A | N/A | 2 | 1 | 2 | 1 | 1 | 2 | 2 | 0.82 | ||

Kim et al
30
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 2 | 1 | 2 | 2 | 2 | 2 | 0 | 0.86 | ||

Ozdemir et al
31
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 2 | 1 | 2 | 1 | 2 | 2 | 2 | 0.91 | ||

Pruchno et al
32
| 2 | 2 | 1 | 2 | N/A | N/A | N/A | 2 | 1 | 1 | 2 | 2 | 2 | 2 | 0.86 | ||

Sharma et al
33
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 2 | 1 | 2 | 1 | 2 | 2 | 2 | 0.91 | ||

Shin et al
34
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 1 | 2 | 1 | 2 | 2 | 1 | 2 | 0.86 | ||

Stajduhar et al
35
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 1 | 1 | 2 | 0 | 2 | 2 | 2 | 0.82 | ||

Tang et al
36
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 2 | 2 | 1 | 2 | 2 | 2 | 2 | 0.95 | ||

Tobin et al
37
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 1 | 2 | 2 | 1 | 2 | 2 | 2 | 0.91 | ||

Wen et al
38
| 2 | 2 | 1 | 2 | N/A | N/A | N/A | 2 | 2 | 2 | 1 | 2 | 2 | 2 | 0.91 | ||

Yoo et al
39
| 2 | 2 | 2 | 2 | N/A | N/A | N/A | 1 | 1 | 1 | 2 | 2 | 2 | 2 | 0.86 | ||

Yun et al
40
| 1 | 2 | 1 | 2 | N/A | N/A | N/A | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 0.91 | ||

Zhang et al
41
| 2 | 2 | 1 | 2 | N/A | N/A | N/A | 1 | 2 | 2 | 2 | 2 | 2 | 2 | 0.91 |

The summary score for each study is derived by calculating the total score of relevant items (ie, all items except those ‘not applicable’) and dividing it by the total possible score when excluding ‘not applicable’ items.

N/A, not applicable.