Document is current

Article History

Accepted: 16 November 2021

First Online: 21 January 2022

Declarationsû

:

: MN has his post funded by the National Institute for Health Research (NIHR) and Health Education England. PR is funded by the NIHR as an academic clinical lecturer. This project required no specific funding.

: FM is a named author on two studies included within the systematic review. Michael Naughton, James Bailey, Liza Bowen, Patrick Redmond, and Mariam Molokhia have no conflicts of interest that are directly relevant to the content of this article.

: Our full data extraction sheet is available in the ESM.

: Stata code for our meta-analysis will be provided by the corresponding author on request.

: Ethical approval was not required for this study. Consent from participants or for publication was not required as we were using publicly available data from previously published studies.

: Not applicable.

: Not applicable.

: MN was involved in the study conceptualisation, writing the protocol, conducting searches, extracting and analysing data, and writing and editing the final manuscript. FM was involved in editing the protocol, analysing the data, and editing the final manuscript. JB was involved in extracting and analysing the data. LB was involved in extracting and analysing the data. MM was involved in supervising the project, study conceptualisation, and editing the protocol and the final manuscript. PR was involved in supervising the project, study conceptualisation.