Correlates of sleep abnormalities in systemic lupus: a cross-sectional survey in an urban, academic center.

BACKGROUND

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that is associated with poor health-related quality-of-life outcomes.

OBJECTIVES

The objectives of this study were to identify correlates of the domains of the Medical Outcomes Study (MOS) Sleep Scale in SLE and to determine the factors most associated with overall sleep quality.

METHODS

Sleep in 118 SLE patients was assessed using the self-administered MOS Sleep Scale. Bivariate correlations were determined between each of 6 MOS Sleep subscale scores and each sociodemographic, clinical, or psychological predictor variable. Serial hierarchical multiple regression analyses were computed to identify the variables associated with the individual sleep domains and the overall Sleep Problems Index.

RESULTS

The MOS Sleep Scale scores of patients with SLE were poorer than the US general population. Depression moderately correlated with 5 (all P < 0.01) and anxiety with 4 subscale scores (all P < 0.05). The SLE Disease Activity Index did not significantly correlate with any of the subscale scores. Results of a multivariate regression model showed that sleep adequacy and sleep disturbance were independently associated with depression (β = -0.84; 95% confidence interval [CI], -1.37 to -0.32; and β = 0.80; 95% CI, 0.15-1.45; respectively). Daytime somnolence was significantly associated with daily prednisone dosage (β = 0.54; 95% CI, 0.29-0.80) and anxiety trait (β = 0.81; 95% CI, 0.41-1.21). Snoring independently correlated with anxiety (β = 1.64; 95% CI, 0.80-2.29). When demographic, clinical, and psychological variables were simultaneously regressed on the Sleep Problems Index, pain trended toward association with overall sleep problems (β = 0.17; 95% CI, -0.02 to 0.36).

CONCLUSIONS

Patients with SLE have greater sleep problems relative to the general population. Psychosocial factors, particularly depression and anxiety, are important determinants that are significantly associated with sleep abnormalities in SLE.