Development of a new patient reported outcome measure (PROM) that will measure the daily burden of gastrointestinal symptoms over the previous 24 hour period for people with cystic fibrosis.

Development of a Patient Reported Outcome Measure (PROM) in line with FDA guidance. The PROM is intended for daily use to measure the symptom burden of gastrointestinal symptoms for people with CF over the last 24 hours.

• Development of the initial conceptual framework underpinning the PROM and confirmed through a patient focus group.
• Primary item (question) generation for the PROM which will then be refined through a series of interviews with people with CF.
• Testing of the items through an online patient questionnaire for testing of frequency, burden and impact of the items.
• Piloting testing of the draft PROM daily for 2 weeks via smartphone app. The recall period of the PROM will be gastrointestinal symptom burden over the previous 24 hours.

Potential participant's will be identified through 6 UK CF care centres at Nottingham University Hospitals NHS Trust (paediatric and adult CF centres), Leeds Teaching Hospital NHS Trust, Manchester University NHS Foundation trust, Royal Brompton and Harefield NHS Foundation Trust and Kings College Hospital NHS Foundation Trust. In addition, recruitment for the survey and trialing the PROM on a smartphone app will also take place via social media and is therefore also open to people with CF from outside these CF centres.

Inclusion Criteria:

• People with cystic fibrosis age 12 years and over
• Confirmed diagnosis of cystic fibrosis based on genotype or sweat chloride testing
• Capacity to consent, or to understand the requirements of the study where parental consent is required

Exclusion Criteria:

• < 12 years age
• Unable to give informed consent

People with cystic fibrosis age 12 years and over