eTable 1. Global assessment of the study’s methodological quality (guided by the “summary assessment of risk of bias” of the Cochrane Collaboration [e1]), relevance for the guideline (3).

Assessment	Methodological quality	Influence on validity of study results
Most relevant	Bias can be largely ruled out or cannot be identified	Low risk of bias; any bias will have at most a small effect on study results
Relevant	Bias can be largely ruled out, slight errors may exist in some areas or cannot be assessed	Low risk of bias; any bias will have at most a small effect on study results
Fairly relevant	Identifiable but not serious bias present in some areas	Uncertain risk of bias; study results may be affected
Relevance doubtful	Slight bias identified in several areas, or some areas cannot be assessed with sufficient certainty because of inadequate description	Risk of bias; study results probably affected
Not relevant	More than slight bias identified in several areas, or such bias cannot be ruled out with sufficient certainty because of inadequate description	High risk of bias; an effect on study results must be assumed