Single- vs. multiple-item instruments in the assessment of quality of life in patients with advanced cancer.

Although multidimensional instruments are usually used to measure quality of life in advanced cancer patients, recent research suggests that single-item assessments can provide a reliable measure. Using the Functional Assessment of Cancer Therapy-General (FACT-G) instrument as a gold standard, we assessed the performance of the Edmonton Symptom Assessment System "feeling of well-being" (ESAS WB) item. We reviewed the data from 213 patients enrolled in six clinical trials. We determined the association between baseline ESAS WB and FACT-G total and subscale domain scores (Physical Well-being [PWB], Social/Family Well-being [SWB], Emotional Well-being [EWB], and Functional Well-being [FWB]. We also calculated the association between baseline (T1) and second (T2) observations of ESAS WB and of FACT-G total score. In addition, we predicted the change in FACT-G predicted by the ESAS WB score using regression analysis. Mean age was 60 (SD 12) years and 48% were female. The Spearman correlation coefficient of ESAS WB and FACT-G was -0.48 (P<0.0001). Correlations with FACT-G subscale domains were also highly significant, except for the SWB domain (P=0.08). The Pearson correlation coefficient for T1-T2 in ESAS WB and FACT-G for 146 patients was -0.36 (P<0.0001). The change in ESAS WB corresponding to FACT-G published minimally important difference was -0.24 for 3, -1.55 for 5, and -2.87 for 7, respectively. These results suggest that the single-item measure ESAS WB best reflects the total score on the FACT-G and PWB, EWB, and FWB domains but not on the SWB domain.