Psychometric testing of the Norwegian version of the Expanded Prostate Cancer Index Composite 26-item version (EPIC-26).

AbstractObjectives: In patients with prostate cancer, evaluation of quality of care requires the inclusion of patient-reported outcomes measures assessed by validated and reliable instruments. Basic psychometric tests of the Norwegian version of the Expanded Prostate Cancer Index Composite with 26 items (EPIC-26) were performed in this study. Material and methods: Translation of the original questionnaire (University of California, Los Angeles Prostate Cancer Index Composite), field testing and retranslation were done according to published guidelines. The final EPIC-26 items were subsequently selected from the Norwegian version of the EPIC-50 with slight verbal adjustments to comply with the English version of the EPIC-26. Reliability and validity were tested among 471 patients who, between 2009 and 2010, had been included in a prospective Norwegian multicenter study assessing adverse effects after radical prostatectomy or prostatic radiotherapy, usually combined with (neo)adjuvant hormone treatment. All...