RESUMEN
Background: Generic and disease-specific patient-reported outcome measures (PROMs) may lack relevance and sensitivity on a patient-level in chronic diseases with differential disease expression and high individual variability, such as Cystic Fibrosis (CF). This study aimed to develop and validate a novel personalized electronic PROM (ePROM) that captures relevant aspects of quality of life in individuals with CF. Methods: The Q-Life app was developed as a short personalized ePROM to assess individual quality of life. Psychometric properties were assessed in a single-center cross-sectional study between September 2019 and September 2021 and in a prospective cohort study between September 2021 and September 2022. Findings: Combined studies included 223 participants (median age: 24 years, IQR: 19.0-32.5 years, range: 12.0-58.0 years). Internal consistency (Cronbach's alpha: 0.83-0.90) and test-retest reliability (intraclass correlation coefficient: 0.90; 95% CI: 0.65-0.92; p < 0.001) of quality of life (Q-Life) scores were strong. Q-Life scores were associated with overall Cystic Fibrosis Questionnaire-Revised (CFQ-R) scores (ρ = 0.71; p < 0.001), CFQ-R respiratory domain scores (ρ = 0.57; p < 0.001) and forced expiratory volume in 1s (ρ = 0.41; p < 0.001). Furthermore, Q-Life scores improved from 65.0 (IQR: 45.0-63.3) at baseline to 84.2 (IQR: 75.0-95.0) and 87.5 (IQR: 75.0-100.0) after 3 and 6 months of elexacaftor/tezacaftor/ivacaftor treatment (change: 20.8; 95% CI: 17.5-25.0; p < 0.001), comparable to CFQ-R respiratory domain scores (change: 22.2, 95% CI: 19.4-25.0, p < 0.001). Interpretation: The Q-Life app is a reliable, valid and sensitive personalized ePROM to measure all aspects of quality of life that really matter to individuals with Cystic Fibrosis. This patient-centered approach could provide important advantages over generic and disease-specific PROMs in the era of personalized medicine and value-based healthcare. Funding: Dutch Cystic Fibrosis Foundation, Health-Holland.