Footnotes

• Contributors PI and SS and GS have written the article, ML, RJ and MM have provided the data. All authors have reviewed the article .

• 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 and public involvement Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the Methods section for further details.

• Patient consent for publication Not required.

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