Table 2 NOS score of 11 studies included in the meta-analysis
| Study | Year | Selection | Comparability | Outcome/Exposure | Score |
|---|---|---|---|---|---|
| Cho [15] | 2018 | ★★★ | ★ | ★★★ | 7 |
| Han [16] | 2018 | ★★★★ | ★★★ | 7 | |
| Kim [17] | 2015 | ★★★ | ★ | ★★★ | 7 |
| Lorente [18] | 2014 | ★★★ | ★★ | 5 | |
| Ozdogan [19] | 2015 | ★★★ | ★ | ★★★ | 7 |
| Wang [12] | 2018 | ★★★ | ★★ | ★★★ | 8 |
| Ding [20] | 2018 | ★★ | ★ | ★★★ | 6 |
| Gong [21] | 2017 | ★★★★ | ★ | ★★★ | 8 |
| Li [22] | 2019 | ★★★ | ★★★ | 6 | |
| Shen [11] | 2016 | ★★★ | ★ | ★★ | 6 |
| Wang [23] | 2015 | ★★★★ | ★ | ★★★ | 8 |