OBJECTIVES: Patients with cystic fibrosis (CF) experience significant disease burden, including progressive pulmonary decline, reduced lifespan, treatment burden, and complex comorbidities. This multicenter study was designed to develop a patient-reported outcomes (PRO) instrument to assess the impact of disease burden on quality of life in patients with CF.

METHODS: Semi-structured qualitative concept elicitation (CE) interviews were conducted with patients and caregivers for patients <18 years. CE interviews elicited qualitative reports of CF-related symptoms, impact of CF, and treatment experiences. After qualitative content analysis, data from CE interviews were considered alongside existing PROs, published literature, and expert opinion to develop a draft measure assessing key CF-related impacts. Three rounds of cognitive interviews evaluated respondent comprehension and supported refinement of the draft cystic fibrosis impact questionnaire (CF-IQ) instrument.

RESULTS: Forty-two patients with CF and 22 caregivers from 8 centers in the US completed CE interviews for CF-IQ development. Patients were between 6 and 58 years and represented a broad range of disease severity (FEVrange 22%-127% predicted); 57% were female, and 88% were white. CE interviews identified 57 unique CF-related impact concepts in domains including: activity limitations (physical, social, leisure); functional limitations (school, work); vulnerability/lack of control; emotional impact; treatment burden; and future outlook CONCLUSIONS: The CF-IQ is a novel PRO developed as a standardized assessment reflecting domains to quantify disease impact in patients with CF. The domains and conceptual framework identified highlight the multifaceted impact of disease burden. CE and cognitive interviews support the content validity of the CF-IQ in patients with CF. Sponsored by Vertex Pharmaceuticals Incorporated