Footnotes

• Contributors CT conceived and designed the study, and contributed to the literature search, data collection, analysis and interpretation of data and writing of the first draft of the manuscript. PGD contributed to the conception and design of the study, analysis and interpretation of data and revision of the manuscript draft. MT contributed to design of the study, analysis and interpretation of data and revision of the manuscript draft. SM and MG contributed to data collection and revision of the manuscript draft.

• 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.

• Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.