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PRISMA flow chart for study screening and selection process.
Adapted with permission from: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6(7): e1000097. Figure 1, Flow of information through the different phases of a systematic review. Available from: http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1000097.
