Selection of Studies
Two reviewers independently searched the literature using the predetermined search criteria and strategy. Subsequently, the reviewers also independently determined the trials for inclusion in the meta-analysis. Any conflict in the process were resolved by another reviewer. The flow of selection of studies was shown using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) diagram. For articles that were not in English language, the authors of the studies in question were contacted for English language-translated copies, if available. English language-translated copies of the studies were in the systematic review.