Footnotes

• UNS and JPS contributed equally.

• Contributors UNS: literature search, writing and editing the manuscript, revision and final approval. JS: planning, literature search, writing and editing the manuscript, revision and final approval. AAP: writing and editing sections of the manuscript, revision and final approval. MNQ: writing and editing sections of the manuscript, revision and final approval. SG: writing and editing sections of the manuscript, critical revision and final approval. MI: writing and editing sections of the manuscript, critical revision and final approval.

• Funding This paper presents independent research funded and supported by the NIHR Birmingham Biomedical Research Centre at the University Hospitals Birmingham NHS Foundation Trust and the University of Birmingham.

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

• Competing interests None declared.

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

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