Footnotes

• Contributors RV, BS-P and LF contributed to the design and implementation of the research. RV and BS-P contributed to the analysis of the results and to the writing of the manuscript. RV, BS-P and LF reviewed and approved 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 for publication Not required.

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