Validation and reliability testing of the EORTC QLQ-NMIBC24 questionnaire module to assess patient-reported outcomes in non-muscle-invasive bladder cancer.

Abstract

Well-developed and well-tested patient-reported outcome measures for non-muscle-invasive bladder cancer (NMIBC) are required. To test and adapt the scale structure and explore the psychometric properties of the European Organisation for Research and Treatment of Cancer (EORTC) questionnaire for NMIBC. A total of 433 patients in the Bladder COX-2 Inhibition Trial (BOXIT) completed the EORTC QLQ-C30 and NMIBC questionnaires. BOXIT is evaluating the addition of celecoxib to standard treatment in high- and intermediate-risk NMIBC. Multitrait scaling investigated and adapted the questionnaire scale structure and evaluated the reliability and validity of the revised scales, as well as responsiveness to change. A total of 410 patients (94.7%) (79.3% men, 74.6% high risk) returned baseline forms, and the questionnaire response rate was 88.2%. Multitrait scaling confirmed six scales and five single items. Scales and items demonstrated significant differences between patients with good and poor performance status scores (p<0.001). Men reported better sexual function than women (p<0.001). Scale and single-item module scores were not highly correlated with QLQ-C30 scores (evidence of discriminant validity), and the module was responsive to changes in health over time. International and test-retest data are required. This study demonstrates the evidence-driven adapted scale structure and psychometric data of the EORTC QLQ-NMIBC24 module to use in clinical trials of patients with high- or intermediate-risk bladder cancer.