1 Sheffield Adult CF Center, Northern General Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Herries Road, Sheffield S5 7AU, UK; School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK. Electronic address: rachaelcurley@nhs.net.
2 School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK. Electronic address: m.j.campbell@sheffield.ac.uk.
3 School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK. Electronic address: s.j.walters@sheffield.ac.uk.
4 School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK; Sheffield Adult CF Center, Northern General Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Herries Road, Sheffield S5 7AU, UK. Electronic address: z.hoo@sheffield.ac.uk.
5 Sheffield Adult CF Center, Northern General Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Herries Road, Sheffield S5 7AU, UK; School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK. Electronic address: martin.wildman3@nhs.net.