Reliability and validity of Amharic version of EORTC QLQ-C30 and QLQ-BR23 modules for assessing health-related quality of life among breast cancer patients in Ethiopia

Background Breast cancer is the most common cancer among women and it affects quality of life of those women. So far, the two most frequently used tools for assessing health related quality of life in breast cancer patients, EORTC QLQ-C30 and EORTC QLQ-BR23 modules, were not validated in Ethiopia. Hence, the present study aimed to assess the psychometric properties of the tools among Ethiopian breast cancer patients. Methods Institutional based longitudinal study was conducted from January 1 to May 1, 2017 GC at only nationwide oncology center, Tikur Anbessa Specialized Hospital (TASH), Addis Ababa, Ethiopia. A total of 146 patients who visited the facility during that period, with no missing quality of life data, were selected for analysis. The psychometric properties of the EORTC QLQ-C30 and EORTC QLQ-BR23 were evaluated in terms of reliability, convergent, divergent, construct and clinical validity using SPSS version 22. Results Satisfactory internal consistency reliability (Cronbach's alpha coefficients > 0.7) was confirmed, except for cognitive function (alpha = 0.516) of EORTC QLQ-C30 and body image (alpha = 0.510) of EORTC QLQ-BR23. Multiple-trait scaling analysis demonstrated a good convergent and divergent validity. No scaling errors were observed. Most items in EORTC QLQ-BR23 possessed a weak or no correlation with its own dimension in EORTC QLQ-C30 (r < 0.4) except with some of symptom scales. A statistically significant chemotherapy induced quality of life scores changes (P <= 0.05) were observed in all dimensions of both instruments between baseline and the end of first cycle chemotherapy, except for body image (P = 0.985) and sexual enjoyment (P = 0.817) of EORTC QLQ-BR23, indicating clinical validity. Conclusion Amharic version of the EORTC QLQ-C30 and EORTC QLQ-BR23 modules are valid and adequately reliable tool and can be used for clinical and epidemiological cancer researches to study the health related quality of life (HRQoL) of women with breast cancer in Ethiopia.