1 North Bristol NHS Trust and University of Bristol, Bristol, UK; Division of Population Medicine, Cardiff University, Cardiff, UK. Electronic address: Christopher.twine@bristol.ac.uk.
2 Centre for Trials Research, Cardiff University, Cardiff, UK.
3 Department of Cardiovascular Sciences and the NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK.
4 MRC Clinical Trials Unit at UCL, Institute of Clinical Trial and Methodology, University College London, London, UK; BHF Data Science Centre, Health Data Research UK, London, UK.