1. West Midlands Adult CF Centre, University Hospitals Birmingham NHS Foundation Trust, Bordesley Green East, Birmingham B9 5SS, UK
2. West Midlands Adult CF Centre, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
3. Institute of Applied Health Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
4. NIHR Birmingham Biomedical Research Centre, University Hospitals Birmingham NHS Foundation Trust and University of Birmingham, Birmingham, UK
5. Clinical Trials Unit, Warwick Medical School, University of Warwick, Coventry, UK