Review of the evidence
Selection criteria for each question were determined a priori .
Only comparative studies (systematic reviews, randomized controlled
trials, cohort studies, case-control studies, and cross-sectional
studies) were considered for inclusion. If randomized data were
available, data from nonrandomized studies were excluded. Electronic and
manual searches were conducted for each question. We searched PubMed and
EMBASE through July 7, 2020. Additionally, we manually reviewed the
reference lists of all relevant systematic reviews and included studies
to find additional eligible studies. The titles and abstracts of all
identified references were reviewed by a clinician and a methodologist
from the GSG. Studies identified for full-text review were then reviewed
by all members of the GSG, and any reasons for exclusion were noted.
Data from included studies were extracted by two members of the GSG. The
quality of evidence from each included study was assessed using the
appropriate risk-of-bias tool for each study design. The Cochrane RCT
tool was used for randomized controlled trials.6 The
Newcastle-Ottawa tool was used for cohort and case-control
studies.7 QUADAS was used for diagnostic accuracy
studies.8 Data on outcomes from similar studies were
pooled when appropriate by using the random-effects model. All analyses
were performed using RevMan,9 and all information was
summarized as evidence profile tables.10