Footnotes

• Contributors MN and SS conceptualised and designed the study. MN and SS participated in the writing of the first draft of the manuscript, reviewed the revisions and approved the final manuscript as 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 for publication Not required.

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