Measuring the Psychosocial Dimensions of Quality of Life in Patients With Advanced Cancer: Psychometrics of the German Quality of Life at the End of Life-Cancer-Psychosocial Questionnaire.
Quality of life (QoL) is a central focus of care in advanced cancer. Specialized instruments, such as the Quality of Life at the End of Life-Cancer (QUAL-EC), may be useful to assess psychosocial issues associated with QoL unique to this population. To evaluate the measurement of the psychosocial dimensions of QoL using the German translation of the QUAL-EC-Psychosocial (QUAL-EC-P) questionnaire, including factor structure and psychometrics. About 183 patients with advanced cancer from the University Medical Center Hamburg-Eppendorf and University Medical Center Leipzig completed the QUAL-EC-P questionnaire. We conducted exploratory factor analysis as well as item and reliability analysis. We examined convergent validity with correlations between the scale and relevant psychological constructs. The sample was 60% female with mean age of 57.7 (SD = 11.7). We extracted three factors accounting for 44% of the variance aligning with the structure of the instrument. The QUAL-EC-P questionnaire showed good to acceptable internal consistency for the QoL-psychosocial total score (α = 0.77), the Life completion subscale (α = 0.77), and the Relationship with health care provider subscale (α = 0.81). The Preparation for end of life subscale had adequate albeit low internal consistency (α = 0.64) because concerns about family were less associated with financial worry and fear of death than expected. The psychosocial dimensions of QoL correlated negatively with depression (r = -0.27, P ≤ 0.001), anxiety (r = -0.32, P ≤ 0.001), demoralization (r = -0.63, P ≤ 0.001), and attachment insecurity (r = -0.51, P ≤ 0.001) and positively with spiritual well-being (r = 0.63, P ≤ 0.001). The QUAL-EC-P questionnaire may be used to assess the psychosocial aspects of QoL and promote their clinical discussion in patients with advanced cancer.