Protocol and sources
The study was developed and completed in compliance with the PRISMA
guidelines.10 The following electronic databases were
searched: PubMed, MEDLINE (via Ovid) and Embase (via Ovid). The
databases were searched from date of first publication until January
2021. We used MeSH and free text terms in conjunction to increase
sensitivity to potentially relevant studies. For details of the search
performed, see Supporting Information Appendix S1. Endnote software (X8;
Clarivate Analytics, Philadelphia, PA, USA) was used to export and
organise the abstracts, and subsequently remove duplicate publications.