Table 2

‚ÄÉCategories of evidence

1AFrom meta-analysis of randomised controlled trials
1BFrom at least one randomised controlled trial
2AFrom at least one controlled study without randomisation
2BFrom at least one type of quasi-experimental study
3From descriptive studies, such as comparative studies, correlation studies, or case-control studies
4From expert committee reports or opinions and/or clinical experience of respected authorities