Footnotes

• Contributors JB designed this work and drafted the manuscript. AMV contributed to the design of the manuscript and critically revised it for intellectual content. Both authors have given final approval of the version submitted.

• 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.