Psychometric Assessment of the Chinese Version of the Abbreviated Expanded Prostate Cancer Index Composite (EPIC-26) and the Clinical Practice Version (EPIC-CP) in Chinese Men With Prostate Cancer

Abstract

PurposeThe Expanded Prostate Cancer Index Composite (EPIC) instrument was designed to assess a range of health-related quality-of-life issues specifically relevant to patients with prostate cancer. This study examined the validity and reliability of Chinese versions of the 26-item EPIC and of the 16-item EPIC for Clinical Practice (EPIC-CP) in Chinese patients with prostate cancer. Materials and MethodsA Chinese version of the 26-item EPIC and the 16-item EPIC-CP were self-completed by 252 Chinese patients with prostate cancer who were recruited from three community-based cancer service centers. Confirmatory factors analysis assessed the factor structures of the EPIC and the EPIC-CP. Internal consistency and construct and clinical validities of the factor structures were assessed. ResultsConfirmatory factor analysis revealed that the original factor structure of both EPIC-26 and EPIC-CP showed good fit to this sample. A correlated model was superior to a hierarchical model in both EPIC-26 and EPIC-CP supporting the utility of the domain scores over the total scores. Cronbach α ranged from 0.55 to 0.91 for EPIC-26 and 0.44 to 0.67 for EPIC-CP. Construct validity was supported by correlations between EPIC-26/EPIC-CP and psychological distress measures. Clinical validity was supported by differentiation between patients with and without prostatectomy. ConclusionsThese Chinese versions of the five-factor EPIC-26 and the EPIC-CP are valid and practical measures for assessing a range of health-related quality-of-life issues related to the diagnosis and treatment of prostate cancer, highlighting their utility in assessing health-related quality of life for patients diagnosed with prostate cancer.