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: Results From A Tobit Regression

The EuroQoL EQ-5D questionnaire is widely used in oncology to generate health-related quality of life (hrQoL) weights and corresponding health states. Aim of this study 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. The study sample included advanced or metastatic CRC patients currently recruited in the German Tumor Registry Colorectal Cancer. The EQ-5D-5L was administered once as paper version alongside the EORTC QLQ-C30 to patients who were at the start or at later stages of palliative treatment. Data on potentially relevant comorbidities, disease-specific health states (e.g. metastases), symptoms (e.g. fatigue), and treatment status were drawn from the clinical registry. A Tobit regression analysis was performed to explore the impact of patient and disease characteristics on the EQ-5D-5L utility score. In total, n=758 questionnaires were sent to patients, n=535 were returned, and n=503 were finally included in the data analysis. Mean age was 66.3 years and 61.2% were male. The overall mean EQ-5D-5L utility score was 0.82, the mean EQ-5D-5L VAS score was 62.05, and the mean EORTC global health status/QoL score was 56.66. The regression analysis revealed that hypertension, fatigue and pain had a significant negative impact on the hrQoL of advanced or metastatic CRC patients (p<0.01). Hypertension reduced the hrQoL score by 0.052, each 1-unit increase in the fatigue symptom scale by 0.003 and in the pain symptom scale by 0.002. This study linking clinical registry data to hrQoL data illustrated a feasible opportunity for a cross-sectional study design. The disease or treatment-related symptoms fatigue and pain negatively affected the hrQoL, whereas other characteristics such as age, gender, and most of the comorbidities did not have a significant impact on hrQoL.