Fatigue in systemic lupus: the role of disease activity and its correlates.

OBJECTIVES: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that leads to a variety of negative health outcomes resulting from inflammation in various organ systems. Although treatment continues to advance, fatigue remains one of the most salient, poorly understood and addressed patient complaints. Understanding the mechanisms of fatigue can help guide the development of interventions to improve health outcomes. The aim of this research was to evaluate the contribution of six variables (disease activity, insomnia, depression, stress, pain and physical health) to fatigue in SLE without concomitant fibromyalgia (FM). METHODS: A total of 116 ethnically diverse, primarily female participants (91%) with SLE, receiving care at university medical centers, completed assessments of disease activity and quality of life outcomes (FACIT-FT, Insomnia Severity Index, Perceived Stress Scale (PSS-4), Pain Inventory, Depression-PHQ-9, and LupusPRO-physical function). All patients met the American College of Rheumatology classification criteria for SLE and did not have a known diagnosis of FM. Multivariate linear and stepwise regression analyses were conducted with fatigue (FACIT-FT) as the dependent variable, and the above six variables as independent variables. RESULTS: Mean (SD) age was 39.80 (13.87) years; 50% were African American, 21% Caucasian, 13% Hispanic, 9% Asian and 8% other. Mean (SD) FACIT-FT was 20.09 (12.76). Collectively, these six variables explained 57% of the variance in fatigue. In the multivariate model, depression, stress and pain were significantly and independently associated with fatigue, but not disease activity, sleep or physical health. Stress had the largest effect on fatigue (ß 0.77, 95% CI 0.17-1.38, p = 0.01), followed by depression (ß 0.66, 95% CI 0.21-1.10, p = 0.005). On stepwise regression analysis, only stress, depression and pain were retained in the model, and collectively explained 56% of the variance in fatigue. All three remained independent correlates of fatigue, with the largest contribution being stress (ß 0.84, 95% CI 0.27-1.42, p = 0.005), followed by depression (ß 0.79, 95% CI 0.44-1.14, p < 0.001) with fatigue. CONCLUSION: Stress, depression and pain are the largest independent contributors to fatigue among patients with SLE, without concurrent FM. Disease activity, sleep and physical health were not associated with fatigue. The evaluation of stress, depression and pain needs to be incorporated during assessments and clinical trials of individuals with SLE, especially within fatigue. This stress-depression-fatigue model requires further validation in longitudinal studies and clinical trials. Significance and innovation: • Disease activity, sleep, pain, stress, depression, and physical health have been reported individually to be associated with fatigue in lupus. This analysis evaluated the role of each and all of these six variables collectively in fatigue among patients with SLE without a known diagnosis of FM. • Disease activity, sleep and physical health were not significantly related to fatigue, but depression, stress and pain were. • The results emphasize the need to evaluate and treat fatigue in individuals with SLE utilizing a biopsychosocial approach, particularly in the realm of clinical trials. Behavioral medicine interventions are shown to be most effective for the treatment of depression, stress and pain.

Body image mediates the impact of pain on depressive symptoms in patients with systemic lupus erythematosus.

OBJECTIVE: Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with treatment manifestations that can cause changes in appearance, including skin rashes, alopecia, vitiligo, and scars. SLE has been shown to adversely impact body image outcomes, and previous research has identified that greater disease activity is associated with worse body image outcomes which, in turn, are associated with greater depressive symptoms. For patients with SLE who also experience significant pain, poor body image outcomes may further compromise wellbeing and lead to greater depressive symptoms. The role of pain in body image has not been explored in SLE. Thus, the present study examined whether body image (specifically, body image-related quality of life) serves as a mediator of the relationship between pain and depressive symptoms among patients with SLE. METHODS: Multiple mediation analysis was used to examine the hypothesis that body image-related quality of life mediates the relationship between pain and depressive symptoms in a sample of patients with SLE (N = 135) from an urban region in Los Angeles, California. RESULTS: The sample was predominately female (92.6%) with a mean disease duration of approximately 17 years. Approximately one-quarter of the sample had elevated depressive symptoms. Body image-related quality of life was a significant mediator in the relationship between pain and depressive symptoms. The model accounted for 51% of the total variance in depressive symptoms (R2 = 0.51). CONCLUSION: This cross-sectional study suggested that body image-related quality of life may mediate the effects of pain on depressive symptoms among patients with SLE.

Validation of the LupusPRO version 1.8: an update to a disease-specific patient-reported outcome tool for systemic lupus erythematosus.

Objectives LupusPRO has shown good measurement properties as a disease-specific patient-reported outcome tool in systemic lupus erythematosus (SLE). For the purpose of clinical trials, the version 1.7 (v1.7) domain of Pain-Vitality was separated into distinct Pain, Vitality and Sleep domains in v1.8, and the psychometric properties examined. Methods A total of 131 consecutive SLE patients were self-administered surveys assessing fatigue (FACIT, SF-36), pain (Pain Inventory, SF-36), insomnia (Insomnia Severity Index), emotional health (PHQ-9, SF-36) and quality of life (SF-36, LupusPRO) at routine care visits. Internal consistency reliability (ICR) for each domain was obtained using Cronbach's alpha. The convergent construct validity of LupusPRO domains with corresponding SF-36 domains or tools were tested using Spearman correlation. Varimax rotations were conducted to assess factor structures of the LupusPRO v1.8. Results Mean (SD) age was 40.04 (14.10) years. Scores from the LupusPRO-Sleep domain strongly correlated with insomnia scores, while LupusPRO-Vitality correlated strongly with fatigue (FACIT) and SF-36 vitality. The LupusPRO-Pain domain correlated strongly with pain (SF36 Bodily-Pain, Pain Inventory) scores. Similarly, the LupusPRO domains of Physical and Emotional Health had significant correlations with corresponding SF-36 domains. The ICR for HRQoL and non-HRQoL were 0.96 and 0.81. LupusPRO (domains HRQoL and QoL) scores correlated with disease activity. Principal component analysis included seven factor loadings presenting for the HRQOL subscales (combined Sleep, Vitality, and Pain), and three factors for the NHRQoL (Combined Coping and Social Support). Conclusions LupusPRO v1.8 (including its Sleep, Vitality, and Pain domains) has acceptable reliability and validity. Use of LupusPRO as an outcome measure in clinical trials would facilitate responsiveness assessment.

Psychometric validation of the Arthritis Helplessness Index in systemic lupus erythematosus.

Objective Helplessness is a relevant construct in systemic lupus erythematosus (SLE), an unpredictable chronic illness with no known cure characterized by relapsing and remitting features. However, no measure of helplessness has been validated in this population. The present study examined the structural validity, reliability, and convergent validity of the Arthritis Helplessness Index, a measure initially developed for rheumatoid arthritis populations, in a sample of patients with SLE. Methods Patients with SLE ( N = 136) receiving medical care at a private hospital completed the Arthritis Helplessness Index and other self-report measures. The structural validity of the Arthritis Helplessness Index was examined using confirmatory factor analysis. Internal consistency reliability was evaluated with Cronbach's coefficient alpha. Pearson product-moment correlations were used to examine convergent validity with measures of depression, anxiety and mastery. Results The five-item Arthritis Helplessness Index-Helplessness measure demonstrated a tenable factor structure (comparative fit index 0.98, root mean square error of approximation 0.06, standardized root mean residual 0.04). Internal consistency reliability was fair (α = 0.69). Convergent validity was evidenced by significant correlations with measures of depression, anxiety and mastery. Conclusion The five-item Arthritis Helplessness Index-Helplessness scale can confidently be used as a measure of helplessness in SLE.

A multi-group confirmatory factor analyses of the LupusPRO between southern California and Filipino samples of patients with systemic lupus erythematosus.

Introduction Systemic lupus erythematosus (SLE) leads to a range of biopsychosocial health outcomes through an unpredictable and complex disease path. The LupusPRO is a comprehensive, self-report measure developed specifically for populations with SLE, which assesses both health-related quality of life and non-health related quality of life. Given its increasingly widespread use, additional research is needed to evaluate the psychometric integrity of the LupusPRO across diverse populations. The objectives of this study were to evaluate the performance of the LupusPRO in two divergent patient samples and the model fit between both samples. Methods Two diverse samples with SLE included 136 patients from an ethnically-diverse, urban region in southern California and 100 from an ethnically-homogenous, rural region in Manila, Philippines. All patients met the ACR classification criteria for SLE. Confirmatory factor analysis (CFAs) were conducted in each sample separately and combined to provide evidence of the factorial integrity of the 12 subscales in the LupusPRO. Results Demographic analyses indicated significant differences in age, disease activity and duration, education, income, insurance, and medication use between groups. Results of the separate CFAs indicated moderate fit to the data for the hypothesized 12-factor model for both the Manila and southern California groups, respectively [χ2 (794) = 1283.32, p < 0.001, Comparative Fit Index (CFI) = 0.793; χ2 (794) =1398.44, p < 0.001, CFI = 0.858]. When the factor structures of the LupusPRO in the southern California and Manila groups were constrained to be equal between the two groups, findings revealed that the factor structures of measured variables fit the two groups reasonably well [χ2 (1697) = 2950.413, df = 1697, p < 0.000; CFI = 0.811]. After removing seven constraints and eight correlations suggested by the Lagrange multiplier test, the model fit improved significantly [χ2 (15) = 147.165, p < 0.000]. Conclusions This research provides significant support for the subscale structure of the LupusPRO in two disparate cultural samples of SLE patients. Despite significant sociodemographic and clinical differences between the two samples, for the most part, the LupusPRO performed similarly in both samples.