Footnotes

• Contributors ALB: original idea, planning, conception and design, patient recruitment, statistical analysis. VE: planning, conception and design, patient recruitment, acquisition of data, completion of source documents, reporting. AL and MR: evaluation of end points and confirmation of inclusion and exclusion criteria. NM: conduct and interpretation of data.

• 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 Obtained.

• Ethics approval CEIC.

• Provenance and peer review Not commissioned; internally peer reviewed.