Fig. 2

Risk of bias summary: review authors’ judgements about each risk of bias item for each included study (worst-case scenario). With regard to the overall RoB judgement, according to the recommendations in the guidance document, if a study is judged to be at low RoB for all domains for a given outcome, we believe that this study has a low RoB overall for this outcome. If a trial is considered to be high RoB in one domain or to have “some concerns” in multiple domains (three or more) for a given outcome, we believe that it has a high overall RoB for this outcome. If a study is judged to raise some concerns in at least one domain for a given outcome, but not to be at high RoB for any one domain, we believe that it has some concerns