Existential well-being is an important determinant of quality of life: Evidence from the McGill quality of life questionnaire

BACKGROUND: The McGill Quality of Life Questionnaire (MQOL) is being developed to correct what we perceive to be a flaw in existing quality of life instruments: neglect of the existential domain. METHODS: This study reports the first use of MQOL for people with cancer at all phases of the disease, including those with no evidence of disease after therapy. RESULTS: The data suggest that MQOL is comprised of an item measuring physical well-being and four subscales: physical symptoms, psychological symptoms, existential well-being, and support. MQOL is acceptable to oncology outpatients. Correlation of the MQOL total and subscale scores with a single item scale measuring overall quality of life and with the Spitzer Quality of Life Index suggests that MQOL has construct and concurrent validity. CONCLUSIONS: The hypothesis that the existential domain is important, especially to those patients with a life-threatening illness, is supported because multiple regression showed that the existential subscale is at least as important as any other subscale in predicting a single item scale measuring the overall quality of life and plays a greater role in determining the quality of life of patients with local or metastatic disease than in patients with no evidence of disease.