Footnotes

• Contributors Conception and design: NK, TS. Collection and interpretation of data: NK, TS, KN, HH, FO. Drafting of the manuscript: NK, TS. Approval of the final version of the manuscript: NK, TS, KN, HH, FO.

• 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.

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

• Data sharing statement There are no additional unpublished data.