Rest/activity rhythm is related to the coexistence of pain and sleep disturbance among advanced cancer patients with pain

Abstract

This study aimed to explore the relationships among pain, sleep disturbance, and circadian rhythms in advanced cancer patients. This cross-sectional study was conducted in 68 cancer patients from the oncology inpatient unit of a teaching hospital. Their demographic and medical characteristics, questionnaire surveys, including Brief Pain Inventory-Chinese version and Pittsburgh Sleep Quality Index Taiwanese version, and sleep logs and actigraphic recordings in consecutive 3 days and nights were collected and analyzed. The mean (SD) scores for autocorrelation coefficient at 24 h (r24) and dichotomy index (I<O) were 0.19 (0.16) and 85.29 % (0.13 %), respectively, indicating dampened circadian rhythms in participants. The mean (SD) worst pain score was 5.47 (2.70). The sleep quality global score ranged 4 ∼ 19 with a mean (SD) of 11.19 (4.05). The worst pain levels, the Pittsburgh Sleep Quality Index (PSQI) global score, and most sleep parameters measured by actigraphy were significantly correlated with r24 and I<O. The worst pain score was significantly correlated with the PSQI global score (r = 0.69, p < 0.01). The Goodman version of the Sobel test further demonstrated that 45.77 % of the total effect was mediated by pain intensity (t = 2.76, p = 0.005). Pain was a complete mediator between circadian rhythms and sleep quality. The rest/activity rhythm influences the coexisting pain and sleep disturbances. Pain functions as a complete mediator in their relationship. Interventions that improve rest/activity rhythms may improve the management of pain and sleep disturbances in cancer patients.