Determinants of sleep quality in women with systemic lupus erythematosus

OBJECTIVE: To characterize sleep complaints in women with systemic lupus erythematosus (SLE) and to identify correlates of sleep quality. METHODS: Sleep quality in 100 women with SLE was assessed using the Pittsburgh Sleep Quality Index (PSQI). Participants completed standardized questionnaires assessing depressed mood, leisure time physical activity, functional disability, and pain severity. A clinical examination determined disease activity, cumulative damage, and whether patients fulfilled the American College of Rheumatology criteria for fibromyalgia. A series of hierarchical multiple regressions were computed. RESULTS: The mean +/- SD global PSQI score was 6.98 +/- 4.03, with moderate to severe sleep impairment reported by 56% of the sample. The first model testing the importance of demographic factors was not statistically significant. In the disease-related model, the use of prednisone and functional disability both contributed to poor sleep quality (P < 0.001). The addition of level of exercise participation to the demographic set significantly added to the model (P = 0.001). Depression significantly added to the demographic set, explaining 29% of the variance (P < 0.0001). When these variables, along with disease related variables, were simultaneously regressed on the PSQI Global Score, only depressed mood appeared as a significant independent determinant of global sleep quality (P < 0.001). However, the point estimates for the Beta coefficients were consistent with effects for lack of exercise and prednisone use. CONCLUSION: A significant proportion of women with SLE suffer from poor sleep quality. The findings suggest that depressed mood, prednisone use, and lack of exercise contribute to decreased overall sleep quality.