Acknowledgments
The reviewers and editors are gratefully acknowledged for critical review.
Contributors Concept and design: CH. Acquisition, analysis, or interpretation of data: CH. Drafting of the manuscript: CH. Critical revision of the manuscript for important intellectual content: CH. Administrative, technical, or material support: CH. The author had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Funding No funding for this study was received.
Competing interests None declared.
Patient consent for publication Not applicable.
Ethical approval Not applicable.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request.