Footnotes

• Contributors BH conceived the idea for the letter and revised the structure, argument and content. GK wrote the original letter and revised the structure, argument and content.

• Funding GK is supported by the Elizabeth Blackwell Institute for Health Research, University of Bristol and the Wellcome Trust Institutional Strategic Support Fund. BH is funded by a National Institute of Health Research Doctoral Fellowship.

• Disclaimer The views expressed are those of the author and not necessarily those of the NHS, the NIHR or the Department of Health.

• Competing interests None declared.

• Patient consent Not required.

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