The Authors' reply.

Competing Interests: Competing interests: JH-C reports grants from the National Institute for Health Research Biomedical Research Centre, Oxford, grants from John Fell Oxford University Press Research Fund, grants from Cancer Research UK (CRUK) grant number C5255/A18085, through the Cancer Research UK Oxford Centre, and grants from the Oxford Wellcome Institutional Strategic Support Fund (204826/Z/16/Z), during the conduct of the study; personal fees and other from ClinRisk (until 2019), outside the submitted work; and is an unpaid director of QResearch, a not-for-profit organisation which is a partnership between the University of Oxford and EMIS Health, which supply the QResearch database used for this work. PST reports consulting with AstraZeneca and Duke-NUS, outside the submitted work.