Sleep, pain, fatigue, and depressive symptoms in cancer patients

Abstract

20523 Background: Sleep disturbance, pain, depression, and fatigue, have been identified as a symptom cluster in patients with cancer because of their frequent co-occurrence. Based on previous research and potential underlying mechanisms, we hypothesized that sleep quality would be positively associated with and mediate the relationship between these symptoms. Methods: The sample included 80 subjects with late stage lung and colorectal cancer with a mean age of 61.01±11.61 years; 39 were female. Sleep quality was measured by the Pittsburgh Sleep Quality Index (PSQI). Pain, depressive symptoms, and fatigue were measured by the bodily pain (BP), mental health (MH), and vitality (VT) subscales of the SF36v2. Statistical analyses included descriptive, correlational, and linear regression. The significance of mediation models was assessed with the Sobel test. Results: Fifty-seven subjects (71%) had poor quality sleep (PSQI score >5); 52 (65%) reported fatigue (VT <50); 43 (54%) had pain (BP <50); and 27 (34%) reported depressive symptoms (MH<50). Symptom expression did not vary by demographic (age, gender, marital status, or education) or clinical (diagnosis, treatment) factors. However, poor sleepers reported more fatigue (p<.001), pain (p=.017), and depressive symptoms (p=.016) than good sleepers. Fifty-eight subjects (73%) expressed 2 or more of the symptoms and correlations between symptoms were positive and statistically significant (r = .339 - .541; p<.01). Multistage regression analyses revealed that sleep partially mediated the association between pain and fatigue (Sobel 3.41; p<.001), between depressive symptoms and fatigue (Sobel 3.57; p=.001), and between pain and depressive symptoms (Sobel 3.28; p<.001). Conclusions: Poor sleep quality, depressive symptoms, fatigue, and pain were prevalent and associated in our sample. While we cannot confirm the direction of these associations, statistical models supported our hypotheses that sleep would mediate associations between symptoms suggesting common or shared underlying mechanisms. Further research into the etiologies of disturbed sleep in cancer populations is warranted as successful interventions to improve sleep quality may decrease expression of pain, fatigue, and depressive symptoms. No significant financial relationships to disclose.