Footnotes

• Contributors AAK: Screening titles, abstracts, and full texts for eligibility; data extraction from the included studies; assessment of risk of bias; data entry in data and analyses tables; conducting meta-analyses; interpreting results; drafting the manuscript; revising the final draft. RSA: Screening titles, abstracts, and full texts for eligibility; data extraction from the included studies; assessment of risk of bias; revising the final draft. AMM: Data entry in data and analyses tables; conducting meta-analyses; interpreting results; drafting the results, discussion, abstract, and plain language summary sections; revising the final draft. MEZ: Providing clinical content expertise and revising the final draft. MAE-W: Data extraction from the included studies; assessment of risk of bias; data entry in the tables of included studies; data entry in data and analyses tables; creating GRADE ‘Summary of findings’ table; revising the final draft. AFN: Performing hand searches and searching reference lists; revising the assessment of risk of bias and resolving disagreements; conducting meta-analyses; creating GRADE ‘Summary of findings’ table; interpreting results; revising the final draft. All authors approved the final draft of the full review. AAK and AFN are guarantors.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Patient consent Not required.

• Provenance and peer review Commissioned; internally peer reviewed.