Study selection:
Decisions to select retrieved studies for further assessment are based
on eligibility criteria. To minimize the chance of including
non-relevant studies, two independent, trained researchers (AK and KA)
went through the abstracts of every article and excluded the ones they
seem unfit the decision to obtain and assess the full text was on
whether one reviewer judged the article as fit for our study.
Subsequently, reviewers (AK, KA) conducted a full text review for all
studies that passed the abstract screening. In case of conflict a third
senior reviewer (MR) was asked to review the articles in question and
decide, independent on what previous researchers decided upon. Two
investigators used a standardized spreadsheet, based on the inclusion
and exclusion criteria, in order to select studies to be included in the
review. Reviewers were trained, and the spreadsheet was piloted prior to
abstract screening.