Table 2.
Risk of bias assessment as analysed by the Cochrane risk of bias tool (Higgins et al., 2016).
| References | Domain A | Domain B | Domain C | Domain D | Domain E | Total |
|---|---|---|---|---|---|---|
| Ahmetov et al., 2015 | Low | Low | Low | Low | Unclear | Low |
| Amir et al., 2007 | Low | Low | Low | Low | Low | Low |
| Ash et al., 2011 | Low | Low | Low | Unclear | Low | Low |
| Döring et al., 2010 | Low | Low | Low | High | Low | Low |
| He et al., 2015 | Low | Low | Low | Low | Low | Low |
| Martinez et al., 2009 | Low | Low | Low | High | High | Unclear |
| Myerson et al., 1999 | Low | Low | Low | Low | Unclear | Low |
| Papadimitriou et al., 2018 | Unclear | Low | Low | Low | Low | Low |
| Posthumus et al., 2011 | Low | Low | Low | Unclear | Low | Low |
| Sawczuk et al., 2013 | Low | Low | Low | Low | Low | Low |
| Stebbings et al., 2017 | Low | Low | Low | Low | Low | Low |
| Tobina et al., 2010 | Low | Low | Low | Low | Low | Low |
| Tsianos et al., 2010 | Low | Low | Low | Low | Low | Low |
| Wolfarth et al., 2008 | Low | Low | Low | Low | Low | Low |
Definition of categories: Domain: (A) sequence generation; (B) allocation concealment; (C) blinding; (D) missing outcome data; (E) selective reporting of results. Total risk of bias grade calculated by assessing the five domains (A–E).