Participants and procedure
All adolescents (12-17 y) and adults (aged ≥ 18 y) with CF visiting the outpatient clinic at the Amsterdam University Medical Centers (Amsterdam UMC) between Sept 2021 and June 2022, were consecutively invited to participate in this prospective, cross-sectional observational study. All participants provided written, informed consent.
Exclusion criteria included: unable to read or poor command of the Dutch language, established diagnosis of a non-functional gastro-intestinal disease, such as inflammatory bowel disease, celiac disease, history of bowel surgery, and severe psychiatric dysfunction, including acute safety risk to self or others. Patients reporting suicidality on question 9 on the Patient Health Questionnaire (PHQ-9), were assessed further. Those reporting suicidal intent were excluded from this study and referred to their care provider.
All participants received either online questionnaires (see section ‘Measures’) through the clinical data management platform25 or paper questionnaires through a member of their CF‐multidisciplinary care team (pediatric psychologist, dietician, specialized nurse, or pediatrician).