Table 2 Classification of evidence-based on best-evidence synthesis approach

1. Strong evidence: evidence provided by two or more high-quality studies and by generally consistent findings across these studies (≥ 75% of the studies reported consistent findings)

2. Moderate evidence: evidence provided by one high-quality study and/or multiple studies of acceptable quality and by generally consistent findings (≥ 75% of the studies reported consistent findings)

3. Limited evidence: evidence provided by one study of acceptable quality and/or one or more studies of borderline quality

4. Conflicting evidence: inconsistent findings in multiple studies (< 75% of the studies reported consistent findings)

5. No evidence: no admissible studies were found