Footnotes

• Contributors MLvD led the review team and provided oversight and statistical expertise, manuscript writing, and gave direction to the group. MDM, RU and JPS contributed to the selection of studies, data extraction, assessment of risk of bias in included studies, pooling of data, manuscript writing and data analysis. PD was part of the original author team and for this update assisted with proofreading and manuscript writing. RD assisted with management of the project, guidance of study team, study inclusion and manuscript writing. MLvD wrote the manuscript for this abbreviated version of the Cochrane review for Heart. MLvD is guarantor.

• Competing interests None declared.

• Patient consent This study was a meta-analysis of published data and did not involve collection of data from individual patients.

• Provenance and peer review Commissioned; internally peer reviewed.