Footnotes

• Contributors GZ was involved in the design and conceptualisation of the study, analysis and interpretation of the data, revising the manuscript for intellectual content; MFL was involved in the analysis and interpretation of the data, revising the manuscript for intellectual content; ST was involved in the conceptualisation of the study, analysis and interpretation of the data, drafting the manuscript. All authors were involved in the final approval of the version to be published.

• Competing interests None.

• Patient consent Obtained.

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