How is sleep quality affected by the psychological and symptom distress of advanced cancer patients?

The aim of this study was to assess the relationship between sleep quality, pain, psychological distress, cognitive status and post-traumatic experience in advanced cancer patients. Participants were 82 advanced cancer patients referred to a palliative care unit for control of pain and other symptoms. A variety of assessment tools were used to examine the prevalence of sleep disturbance, the severity of pain and depression, hopelessness, cognitive function and quality of life. Using the Pittsburgh Sleep Quality Index (PSQI) 96% of patients were 'poor sleepers'. Statistically significant associations were found between PSQI and the SF-12 (Short Form-12) Quality of Life Instrument (MCS, P < 0.0005, PCS, P < 0.0005), depression (Greek Depression Inventory) (P < 0.0005) and hopelessness (Beck Hopelessness Scale) (P = 0.003). Strong associations were also found between PSQI and IES-R (Impact of Event Scale-Revised) (P = 0.004). The strongest predictors of poor sleep quality in this model were MCS (P < 0.0005), PCS (P < 0.0005) and IES-R (P = 0.010). Post-traumatic experience and quality of life seemed to be the strongest predictors of sleep quality in a sample of advanced cancer patients referred for palliative care.