Pain, sleep disturbance, and fatigue symptom cluster in patients suffering from chronic chemotherapy-induced neuropathic pain (CINP).

Abstract

9113 Background: Various symptom cluster combinations of pain, fatigue, sleep disturbance (SD), and depression have been identified in cancer patients. The presence of symptom clusters has not been assessed in patients with persistent CINP. This exploratory analysis aimed to determine which symptoms statistically clustered with pain in cancer survivors with CINP. Methods: The University of Rochester Cancer Center Community Clinical Oncology Program recruited 461 patients with CINP > 4 (on a 0-10 scale) who had completed chemotherapy (median 7 months ago) for a pain intervention trial. At baseline, groups of highly associated symptoms that included pain were identified empirically using factor and cluster analyses of the 11 symptoms in the University of Rochester Symptom Inventory plus the Hospital Anxiety and Depression Scale (HADS) scores. To investigate if associated symptoms track together over time, multiple linear regression (MLR) analysis was performed using changes in symptom severity between baseline and week 6, controlling for gender, age, education, race, and marital status. Results: Subjects were 88% white and 71% female, and on average 61 years old. Mean (standard deviation) baseline pain, fatigue, and SD were 5.7 (2.8), 5.0 (2.7), and 4.2 (3.1), respectively; 26% of subjects had borderline or abnormal HADS scores. Factor analysis identified 3 factors that accounted for 88% of the variance. One factor included pain, fatigue, SD, but not HADS, and accounted for 37% of the variance. Variable clustering also identified pain, SD, and fatigue as 1 symptom cluster. Changes in severity of SD and fatigue (p < 0.0001), but not HADS, were associated with changes in pain (adjusted R2 = 0.168) in MLR analysis. Conclusions: Pain, fatigue, and SD were identified as a symptom cluster by factor and cluster analyses, and were found to track together over time by MLR. Since these data suggest that pain is associated with sleep quality and fatigue in patients with persistent CINP, targeting one of these symptoms may lead to reductions in the others. Future research should investigate interventions that target pain, fatigue, and SD concurrently in cancer survivors suffering from CINP.