Risk of bias assessment
The two authors (Y.O. and F.M.) independently assessed the risk of bias
of the included studies for each outcome using the Revised Cochrane risk
of bias tool for RCT (RoB 2.0) 9 and the Risk of Bias
in Non-randomized Studies of Interventions (ROBINS-I) tool for
non-randomized studies 10. The following five domains
of the risk of bias were assessed for RCTs: randomization process,
deviations from the intended intervention, missing outcome data,
measurement of the outcome, and selection of the reported result.
Conflicts of assessment between the two reviewers were resolved through
discussion, with the third reviewer (T.I.) adjudicated it, if needed.
Assessment of certainty of evidence and summary tables The Grading of Recommendations, Assessment, Development, and
Evaluations (GRADE) approach was used to assess the certainty of
evidence for each outcome across the studies. Certainty of evidence was
categorized into four levels (high, moderate, low, or very low) and
summarized in an evidence profile table. 11,12 As
recommended by the GRADE approach, 11,13 certainty of
evidence was preliminarily started as “high” for not only RCTs but
also non-randomized studies because the risk of bias in non-randomized
studies was assessed according to ROBINS-I on the same metrics as those
of RCTs. 10 The certainty of evidence was downgraded
for risk of bias, imprecision, inconsistency, indirectness, and
publication bias. For assessing imprecision, the sample size required to
detect a 20% risk ratio [RR] reduction, called “optimal
information sizes,” was calculated using total event rates in the
control groups of the included studies. 11,13