Psychometric validation of the Body Image Scale in patients with breast cancer

Abstract

Abstract Objective Patients with breast cancer often have changes in body image after surgery. The Body Image Scale (BIS) is one useful scale for measuring body image. However, the BIS has not been validated in patients with breast cancer in Taiwan. The purpose of this study was to examine the unidimensionality, reliability, and convergent validity of the BIS in breast cancer patients. Methods Patients were recruited if they were diagnosed with breast cancer and had received cancer-related surgery. Unidimensionality and Rasch reliability were validated with Rasch model and principle component analysis. Convergent validity was examined by calculating the association between the Rasch scores of the BIS and the WHOQOL-BREF and the utility value of the EQ-5D. Results A total of 713 patients participated in this study. The fit indices of each item of the BIS ranged from 0.7 to 1.2, and the unexplained variance of the first dimension was 6.3%. The mean person reliability of the BIS was 0.70. Pearson’s r between the BIS and the WHOQOL-BREF/ EQ-5D ranged from − 0.53 to -0.32. Conclusions The results of Rasch analysis supported that the items of the BIS were unidimensional. The BIS had acceptable person reliability and good convergent validity in patients with breast cancer. The health providers can use the BIS to measure body image of patients with breast cancer and provide further interventions to patients with high BIS scores.