1. Department of Public Health and Policy, University of Liverpool, Liverpool, UK
2. National Heart and Lung Institute, Imperial College London, London, UK
3. Department of Paediatric Respiratory Medicine, Royal Brompton and Harefield NHS Foundation Trust, London
4. Cystic Fibrosis Trust, Aldgate, London, UK
5. Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK
6. Centre for Health Informatics, Computing and Statistics (CHICAS), Lancaster University, Lancaster, UK
7. Translational Medicine, Hospital for Sick Children and Institute of Health Policy Management and Evaluation, University of Toronto, Toronto, ON, Canada