Footnotes

• Contributors YLL and RV were involved in the conception and design of the work. YLL was the main author who wrote the manuscript. Both RV and FY provided the patients and reviewed the manuscript critically. All authors approved the final document and are accountable for all aspects of the work.

• 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.

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

• Patient consent for publication Next of kin obtained.