Application study of the EQ-5D-5L in oncology: Linking self-reported quality of life of patients with advanced or metastatic colorectal cancer to clinical data from a German tumor registry

Background: The EQ-5D-5L questionnaire is used in oncology to generate health-related quality of life (HRQoL) weights and corresponding health states. The purpose was to explore the relationship between demographic and clinical characteristics and HRQoL among advanced or metastatic colorectal cancer (CRC) patients by linking clinical data of a German CRC registry to self-reported HRQoL measures from the EQ-5D-5L. Methods: The study sample included patients with advanced or metastatic CRC currently recruited in the German Tumor Registry Colorectal Cancer. The EQ-5D-5L was administered once to patients who were at the start or at later stages of palliative treatment. Data on comorbidities, disease-specific health states, symptoms, and treatment status were drawn from the registry. Multivariate regression analyses were performed to explore the impact of patient and disease characteristics on HRQoL. Results: In total, n = 433 questionnaires were included in the data analysis. Mean age of patients was 66.3 years and 61.2% were male. The mean EQ-5D-5L utility score was 0.82 and the mean EQ-5D-5L VAS score was 62.05. The regression analyses revealed that none of the demographic characteristics and few of the clinical characteristics, such as fatigue and pain, had a significant impact on the HRQoL. Conclusions: The study demonstrated a reduced HRQoL of patients with advanced or metastatic CRC when compared to the general population. The symptoms fatigue and pain negatively affected the HRQoL, whereas other characteristics such as age, gender, and comorbidities did not have a significant impact on HRQoL.