Fatigue is common among individuals with systemic lupus erythematosus (SLE), but the causes are not well understood. Our objective was to examine perceived stress and depressive symptoms as predictors of fatigue in SLE.
Data from 2 years of the Lupus Outcomes Study (n = 650 patients), obtained through annual structured interviews, were used. Fatigue was measured with the Short Form 36 (SF-36) vitality scale along with a variety of self-report measures of disease, depression, and stress. Multivariate linear regression models examined predictors of changes in fatigue. Model 1 tested the association of time 1 (T1) depression with time 2 (T2) fatigue; model 2 added T1 perceived stress to model 1, and final models added T1-to-T2 decrease in stress. All analyses controlled for T1 fatigue, age, sex, self-report of fibromyalgia, pain, and SLE duration, activity, and damage.
Mean ± SD age was 51 ± 12 years, 92% of participants were women, and 68% were white. The mean ± SD SF-36 fatigue score was 55 ± 24. T1 depression significantly predicted T2 fatigue. When T1 stress was added, stress (β = 1.7 [95% confidence interval (95% CI) 1.1, 2.2]; P < 0.0001) significantly predicted T2 fatigue, but depression was no longer significant. The addition of T1-to-T2 decrease in stress was associated with a clinically meaningful decline in fatigue (β = -11.8 [95% CI -15.6, -8.9]; P < 0.0001).
While depressive symptoms initially predicted subsequent fatigue, the effects were mediated by stress. A decrease in stress, in addition, was associated with a clinically meaningful decrease in fatigue. These results suggest that perceived stress plays an important role in SLE fatigue and may be an important focus of interventions for fatigue.