Table 2.

Best-evidence synthesis

Strong evidence	Consistent findings among multiple high-quality trials*
Moderate evidence	Consistent findings in multiple low-quality trials and/or one high-quality trial
Limited evidence	Consistent findings in at least one low-quality trial
Conflicting evidence	Inconsistent findings among multiple trials (high- and/or low-quality trials)
No evidence	Findings of eligible trials do not meet the criteria for one of the levels of evidence stated above, or there are no eligible trials available

* Consistent findings were defined as ≥75% of the trials showing results in the same direction.