Assessing the independent contribution to quality of life from anxiety and depression in patients with advanced cancer

BACKGROUND: The aim of palliative care services is to ensure the best quality of life for patients and their carers. Depression is common amongst palliative care patients and has been shown to adversely affect quality of life. This study aimed to examine the independent contribution of depression to quality of life. OBJECTIVE: To investigate the hypothesis that a) illness severity, pain, anxiety and depression are all associated with impaired health-related quality of life and b) once the effects of illness severity have been adjusted for, there is further independent contribution to quality of life from anxiety and depression. METHOD: Consecutive patients with advanced cancer under the care of palliative care services were screened. Sixty-eight patients were evaluated for levels of anxiety and depression, severity of illness, pain severity and health-related quality of life. RESULTS: Thirty-three males and 35 females were recruited and had an age range of 41-93 years (median 71). Seventeen (25%) of patients were anxious anxiety score > or = 11 on the Hospital Anxiety and Depression Scale (HADS), 15 (22%) were depressed (HADS depression score > or = 11). After controlling for the effects of pain and illness severity, anxiety and depression were independently associated with global health status, emotional and cognitive functioning, and fatigue. Anxiety further contributed significantly towards social functioning, nausea and vomiting. CONCLUSIONS: This study has confirmed that pain, anxiety and depression were associated with impaired quality of life. Anxiety and depression contributed independently towards various dimensions of quality of life. Longitudinal studies are required to examine the direction of the causal association between pain and depression in patients receiving palliative care.