Psychometric validation of the Cystic Fibrosis Impact Questionnaire (CF-IQ): A patient-reported outcome assessing impacts of cystic fibrosis.
| Title: | Psychometric validation of the Cystic Fibrosis Impact Questionnaire (CF-IQ): A patient-reported outcome assessing impacts of cystic fibrosis. |
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| Authors: | Serrano D; Pharmerit International-An OPEN Health Company, Bethesda, MD, United States of America.; The Psychometrics Team, Sheridan, WY, United States of America.; Uzumcu A; Pharmerit International-An OPEN Health Company, Bethesda, MD, United States of America.; Gerstein M; Pharmerit International-An OPEN Health Company, Bethesda, MD, United States of America.; Ayasse ND; Pharmerit International-An OPEN Health Company, Bethesda, MD, United States of America.; Engstrom E; Pharmerit International-An OPEN Health Company, Bethesda, MD, United States of America.; Barnes FB; Pharmerit International-An OPEN Health Company, Bethesda, MD, United States of America.; Iaconangelo C; Pharmerit International-An OPEN Health Company, Bethesda, MD, United States of America.; Thorat T; Vertex Pharmaceuticals Incorporated, Boston, MA, United States of America.; McGarry LJ; Vertex Pharmaceuticals Incorporated, Boston, MA, United States of America.; Sermet-Gaudelus I; INSERM U1151, Université Paris Cité, Centre de Références Maladies Rares Mucoviscidose et Maladies Apparentées, Hôpital Necker Enfants Malades, Paris, France. |
| Source: | PloS one [PLoS One] 2025 Jan 24; Vol. 20 (1), pp. e0317775. Date of Electronic Publication: 2025 Jan 24 (Print Publication: 2025). |
| Publication Type: | Journal Article; Validation Study |
| Language: | English |
| Journal Info: | Publisher: Public Library of Science Country of Publication: United States NLM ID: 101285081 Publication Model: eCollection Cited Medium: Internet ISSN: 1932-6203 (Electronic) Linking ISSN: 19326203 NLM ISO Abbreviation: PLoS One Subsets: MEDLINE |
| Imprint Name(s): | Original Publication: San Francisco, CA : Public Library of Science |
| MeSH Terms: | Cystic Fibrosis*/psychology ; Psychometrics*/methods ; Patient Reported Outcome Measures*; Humans ; Male ; Female ; Adult ; Surveys and Questionnaires ; Middle Aged ; Reproducibility of Results ; Young Adult ; Quality of Life ; Adolescent ; Focus Groups |
| Abstract: | The Cystic Fibrosis (CF) Impact Questionnaire (CF-IQ) was qualitatively developed to assess the impact of CF in the context of treatment advancements and increased longevity. This study reports the CF-IQ validation. In this noninterventional validation study, people with CF completed the 40-item CF-IQ and validating patient-reported outcome measures (PROMs) via electronic diaries at enrollment (baseline) and at the 4-week follow-up. Validation consisted of modern methods and focus groups to finalize structural validity, and classical methods to assess internal consistency [1-3], test-retest reliability [4,5], concurrent validity [5], and known-groups validity [5] of the CF-IQ. At baseline, 214 adults completed the survey; 193 completed the follow-up survey. Unidimensional item response theory (IRT) models were separately fit to 5 prespecified domains (Control and Burden of CF Treatment Impacts, Physical Activity Impacts, Social Activity Impacts, Emotional Impacts, and Work/School Limitation Impacts). IRT local dependence (LD) statistics identified 17 redundant items. Two independent CF-patient focus groups (14 total patients) confirmed these findings, and the 17 items were dropped. Each domain defined on the final 23 items achieved the criterion of exact model fit as measured by the root mean squared error of approximation (RMSEA, values = 0), Internal consistency (Cronbach's α) values ranged from 0.81 to 0.89, 4 of 5 domains achieved acceptable test-retest reliability, with intraclass correlation coefficient (ICC) values ≥ 0.7, acceptable concurrent validity was achieved for all domains, and known-groups validity was established. The novel CF-IQ is a psychometrically robust PROM capturing patient-centric impacts of CF in the context of the current standard of care.; (Copyright: © 2025 Serrano et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.) |
| Competing Interests: | I have read the journal’s policy and the authors of this manuscript have the following competing interests: DS, AU, MG, NDA, EE, FBB, and CI were employees of Pharmerit International – An OPEN Health Company, which received funding from Vertex Pharmaceuticals, Inc. CI is currently an employee of Janssen Global Services, LLC. TT and LJM are employees of, receive salary from, and may own stock or stock options of Vertex Pharmaceuticals, Inc. ISG is on the faculty at and receives salary from Institut Necker-Enfants Malades Hospital, Paris, France; she has participated as a principal investigator on clinical studies for Vertex Pharmaceuticals, Inc. |
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| Entry Date(s): | Date Created: 20250124 Date Completed: 20250124 Latest Revision: 20250523 |
| Update Code: | 20260130 |
| PubMed Central ID: | PMC11761112 |
| DOI: | 10.1371/journal.pone.0317775 |
| PMID: | 39854524 |
| Database: | MEDLINE |
Journal Article; Validation Study