Footnotes

• Contributors All authors contributed to the study design. BA, AIU and MKT collected study data. All the authors drafted the manuscript and reviewed and approved the final 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; internally peer reviewed.