Modeling hot flushes and quality of life in breast cancer survivors

Abstract

Objectives: To evaluate the relationships among measures of hot flushes, perceived hot flush interference, sleep disturbance, and measures of quality of life while controlling for potential covariates (patient and treatment variables). Methods: Breast cancer survivors (n = 395) due to receive aromatase inhibitor therapy provided demographic information, physiological hot flush data via sternal skin conductance monitoring, hot flush frequency via written diary and electronic event marker, hot flush severity and bother via written diary, and questionnaire data via the Hot Flash Related Daily Interference Scale, Pittsburgh Sleep Quality Index, the EuroQOL, Hospital Anxiety and Depression Scale and the Center for Epidemiologic Studies Depression Scale. Results: Confirmatory factor analysis supported a two-factor model for hot flush symptoms (frequency and severity). Although there was strong convergence among self-reported hot flush measures, there was a high degree of unexplained variance associated with physiological measures. This suggests that self-report and physiological measures do not overlap substantially. The structural model showed that greater hot flush frequency and severity were directly related to greater perceived interference with daily life activities. Greater perceived interference, in turn, directly predicted greater sleep disruption, which predicted lower perceived health state and more symptoms of anxiety and depression. Conclusions: Findings suggest hot flush interference may be the most appropriate single measure to include in clinical trials of vasomotor symptom therapies. Measuring and ameliorating patients' perceptions of hot flush interference with life activities and subjective sleep quality may be the most direct routes to improving quality of life.