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

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.

Validation and reliability of the Dutch version of the EORTC QLQ-BLM30 module for assessing the health-related quality of life of patients with muscle invasive bladder cancer

“…Furthermore, the test-retest analysis indicated that the scores on this scale varied more than would be desirable in generally stable patients, and no large differences were observed for this scale in patients who experienced changes in health over time. Similar results have been observed for this scale in patients diagnosed with NMIBC [ 7 , 8 ]. However, the correlation between the items of the bloating and flatulence scale was higher for patients treated with RC compared to the total MIBC population.…”

“…This finding is in line with other studies [ 7 , 22 , 25 ], but nevertheless resulted in the exclusion of female sexual function and the item single catheter use from the CFA. The new grouping of the items addressing sexual function is the same as proposed and confirmed for the QLQ-NMIBC24 [ 7 , 8 , 25 ], and therefore, we expect that this new grouping of the sexual items will be sustained in future studies investigating the measurement properties of the QLQ-BLM30.…”

“…HRQoL outcomes are typically assessed with patient-reported outcome measures (PROMS). There are currently a number of PROMs designed to assess the HRQoL of patients with BC, including: the Bladder Cancer Index (BCI) [4]; the Functional Assessment of Cancer Therapy questionnaire for bladder cancer patients in general (FACT-Bl) and for those who undergo a cystectomy (FACT-VCI) [5,6]; and the European Organisation for Research and Treatment of Cancer (EORTC) questionnaires for NMIBC (EORTC-QLQ-NMIBC24) [7,8] and MIBC (EORTC-QLQ-BLM30) [9]. A major limitation of many of these PROMs is the lack of validation studies demonstrating that these PROMs can accurately measure what they intend to measure [10].…”

Quality of Life in Patients with High-grade Non–muscle-invasive Bladder Cancer Undergoing Standard Versus Reduced Frequency of Bacillus Calmette-Guérin Instillations: The EAU-RF NIMBUS Trial

“…Domains such as sexual functioning, self-consciousness, embarrassment, and psychological distress are of greater importance in BC patients but are not assessed thoroughly by the QLQ-C30 questionnaire [17] . Several BC-specific questionnaires have been designed to offer an instrument that closes these gaps, such as the EORTC QLQ-NIMBC24 questionnaire, which has shown excellent measurement properties with regard to validity, reliability, and responsiveness [18] , but this did not exist at the time of the original trial design.…”