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Validation and reliability of the Dutch version of the EORTC QLQ-NMIBC24 Questionnaire Module for patients with non-muscle-invasive bladder cancer

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Theodora M. Ripping, Ellen Westhoff, Neil K. Aaronson, Mieke Van Hemelrijck, Elke Rammant, J. Alfred Witjes, Lambertus A. Kiemeney, Katja K.H. Aben, Alina Vrieling

Original languageEnglish
Article number96
Number of pages1
JournalJournal of Patient-Reported Outcomes
Volume5
Issue number1
DOIs
Published1 Sep 2021

Bibliographical note

Funding Information: The UroLife study is funded by Alpe d’HuZes/Dutch Cancer Society (KUN 2013-5926) and Dutch Cancer Society (Project No. 11179). The BlaZIB study is funded by the Dutch Cancer Society (IKNL 2015-7914). The funding agencies had no role in the design, data collection, analysis, and interpretation of the results of this study. Funding Information: We are grateful to all the patients who participated in UroLife and BlaZIB and thank all hospitals who were involved in the recruitment of patients. The authors also thank the research assistants for the HRQL data collection and the registration team of the Netherlands Comprehensive Cancer Organisation (IKNL) for the collection of data for the Netherlands Cancer Registry. We would like to thank the following hospitals for their involvement in recruitment for the UroLife study: Amphia Ziekenhuis, Breda/Oosterhout (Drs. D.K.E. van der Schoot); Ziekenhuis Bernhoven, Uden (Drs. A.Q.H.J. Niemer); Canisius-Wilhelmina Ziekenhuis, Nijmegen (Dr. D.M. Somford); Catharina Ziekenhuis, Eindhoven (Dr. E.L. Koldewijn); Deventer Ziekenhuis, Deventer (Drs. P.L.M. van den Tillaar); Elkerliek Ziekenhuis, Helmond (Drs. E.W. Stapper ?, Drs. P.J. van Hest); Gelre Ziekenhuizen, Apeldoorn/Zutphen (Drs. D.M. Bochove-Overgaauw);. Publisher Copyright: © 2021, The Author(s). Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

King's Authors

Abstract

Background: The European Organisation for Research and Treatment of Cancer (EORTC) quality of life questionnaire for non-muscle invasive bladder cancer (QLQ-NMIBC24) has been available and applied for some years now, but has yet to undergo a full comprehensive psychometric evaluation. The aim of this study was to investigate the psychometric properties of the Dutch version of the EORTC QLQ-NMIBC24 questionnaire in patients with low, intermediate and high risk NMIBC. Methods: We included patients newly diagnosed with NMIBC participating in the multicenter, population-based prospective cohort studies UroLife or BlaZIB. Psychometric evaluation included examination of the structural validity, reliability (i.e. internal consistency and test–retest reliability), construct validity (i.e. divergent validity and known-groups validity), responsiveness and interpretability. Results: A total of 1463 patients who completed the baseline questionnaire of UroLife (n = 541, response rate 50%) or BlaZIB (n = 922, response rate 58%) were included. The percentage of missing responses were low for all non-sex related scales (< 1%) and ranged between 6.9% to 50.0% for sex-related scales. More than 15% of the patients obtained the lowest possible scores on nearly each scale (floor effect). The structural validity was adequate; the confirmatory factor analysis showed satisfactory results and all items of multiple items scales had higher within- than between-scale correlations. Reliability of the questionnaire was adequate for most multiple item scales (Cronbach’s α ≥ 0.70 and intraclass correlation coefficient ≥ 0.70), with exception of the scales ‘malaise’ and ‘bloating and flatulence’. The questionnaire also showed good construct validity; it showed low correlations with the items of the EORTC core questionnaire and was able to measure differences between risk-based subgroups. The responsiveness of the questionnaire was good, but the interpretability, i.e. minimal important change, could not be determined. Conclusions: This study shows that the measurement properties of the EORTC QLQL-NMIBC24 are good; it has a good structural validity, reliability (i.e. internal consistency and test–retest reliability), construct validity (i.e. divergent validity and known-group validity), and responsiveness. Interpretability could not be assessed. This questionnaire can be used to measure and monitor health-related quality of life of patients with NMIBC.

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