1. Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom
2. Cancer Research UK Oxford Centre, University of Oxford, Oxford, United Kingdom
3. Division of Primary Care, School of Medicine, University of Nottingham, United Kingdom
4. Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
5. Intensive Care National Audit and Research Centre, London, United Kingdom
6. Oxford Biomedical Research Centre, Oxford University Hospitals NHS Trust, Oxford, United Kingdom