Search methods
Expertise	The searches will be informed by a content expert, conducted by an information specialist Mike Smalle, and independently peer reviewed.
Electronic databases	Database [minimum checked – please specify one other] ☒ MEDLINE ☐ CENTRAL ☐ Embase ☐ Other ☐ Clinical trials registry (please specify)	From: 2002		To: 2020
Other searches	☒ Systematic review references ☒ Reference lists of included studies ☐ Grey literature (please specify) ☐ Citation tracking ☐ Data from the pharmaceutical industry ☐ Contact experts for references ☐ Other (please specify)	We will examine reference lists of included studies for relevance.
Approach to ongoing and unpublished studies	☐ Include ongoing studies ☐ Unpublished studies ☒ Studies in press ☐ Exclude all studies that are ongoing, unpublished, or in press
Methods for screening search results
Expertise	Screening will be performed by methodologists (CH, LB, PM, HD) in Covidence
Screening methods	Dual; second review author checks all excluded records Dual; second author checks 30% of excluded records Dual; independent screen and cross‐check		Abstract ☐ ☒ ☐		Full text ☒ ☐ ☐
Discrepancy resolution	☒ Consensus and/or third review author ☐ Other (please specify)
Excluded studies	All decisions taken during screening will be documented and outlined in the final report with a list of excluded studies
Inclusion of abstracts and conference proceedings	☒ Exclude all ☐ Include if clearly eligible and have usable data ☐ Include if clearly eligible regardless of usable data ☐ Include if eligibility is unclear and add to section in report
Inclusion of non‐English‐language studies	☒ Include abstracts and full texts in any language ☐ Include full texts only ☐ Exclude
	☐ All potentially relevant abstracts will progress to full‐text screen ☐ [Single/dual] title/abstract screen by foreign‐language speaker(s) ☐ [Abstract/methods/full text] will be translated for abstract/full text screen ☒ Listed as non‐English language and not assessed further