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. 2021 Sep 17;11(9):e050532. doi: 10.1136/bmjopen-2021-050532

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© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

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PRISMA flow chart: search strategy. ICTRP, International Clinical Trials Registry Platform; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.