Footnotes

• Contributors All authors contributed to conception and design of the work, drafted and revising it for critically for important intellectual content and provided final approval of the version to be published.

• 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 ANB, LL and GIL: none to report. JRS: receives royalties or licenses from uptodate and is a member, Board of Trustees for the American College of Gastroenterology.

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