Correlates of disrupted sleep-wake variables in patients with advanced cancer.

Objectives: High rates of sleep difficulties have been found in patients with advanced cancer. However, not much is known about factors that are associated with sleep impairments in this population and that could constitute their potential risk factors or consequences. This study conducted in patients with cancer receiving palliative care aimed to evaluate the relationships of subjective (sleep diary; Insomnia Severity Index, ISI) and objective (actigraphy) sleep-wake variables with several physical and psychological symptoms, maladaptive sleep behaviours, erroneous beliefs about sleep, quality of life, time to death and environmental factors.

Methods: The sample was composed of 57 community-dwelling patients with cancer receiving palliative care and with an Eastern Cooperative Oncology Group Scale score of 2 or 3. Actigraphic, light and sound recording and a daily sleep and pain diary were completed for seven consecutive days. A battery of self-report scales was also administered.

Results: Greater disruptions of subjective and objective sleep-wake variables were more consistently associated with worse physical symptoms than with psychological variables. Disrupted objective sleep-wake parameters were also associated with a greater frequency of maladaptive sleep behaviours. Finally, a greater nocturnal noise in the bedroom was correlated with more impairments in subjective and objective sleep-wake variables while a lower 24-hour light exposure was associated with more disruption of subjectively assessed sleep only.

Conclusions: Although longitudinal studies are needed to establish the etiology of sleep-wake difficulties in patients with advanced cancer, our findings suggest that physical symptoms, maladaptive sleep behaviours and environmental factors can contribute to their development or their persistence and need to be adequately addressed.