Table 4 Risk of bias of included studies
Author | Year | Study participation | Study attrition | Prognostic factor measurement | Outcome measurement | Study confounding | Statistical analysis and reporting | Overall risk of bias |
|---|---|---|---|---|---|---|---|---|
Cho, C.H. | 2015 | High | Low | Low | Low | High | High | High |
Cho, N.S. | 2015 | Moderate | High | Low | Moderate | High | High | High |
Tan, M. | 2016 | Moderate | Moderate | Moderate | High | High | High | High |
Burrus, M.T | 2019 | Moderate | Moderate | High | Low | Low | Moderate | High |
Harada, G.K. | 2019 | High | High | Moderate | Low | Low | High | High |
Cucchi, D. | 2020 | Moderate | Low | High | High | High | High | High |
Takahashi, R. | 2020 | High | High | Moderate | Moderate | High | High | High |