Footnotes

• Twitter @Hassanmahmooddr, @ddfriedman

• Correction notice This article has been corrected since it published Online First. The twitter handle for Dr Mahmood has been added and the provenance and peer review statement has been included.

• Contributors HM was responsible for the conception and initial draft of the manuscript. DJF was involved in revised drafting and critical revision of the manuscript.

• 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 DJF is an associate editor for BJSM.

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