Footnotes

• Contributors All authors (OFA, DS, LBL) contributed equally to the intellectual content, drafting, critical revisions and final approval of the manuscript.

• 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 Not commissioned; externally peer reviewed.