Predictors of Fatigue Severity in Early Systemic Sclerosis: A Prospective Longitudinal Study of the GENISOS Cohort

Abstract

ObjectivesLongitudinal studies examining the baseline predictors of fatigue in SSc have not been reported. Our objectives were to examine the course of fatigue severity over time and to identify baseline clinical, demographic, and psychosocial predictors of sequentially obtained fatigue scores in early SSc. We also examined baseline predictors of change in fatigue severity over time.MethodsWe analyzed 1090 longitudinal Fatigue Severity Scale (FSS) scores belonging to 256 patients who were enrolled in the Genetics versus Environment in Scleroderma Outcomes Study (GENISOS). Predictive significance of baseline variables for sequentially obtained FSS scores was examined with generalized linear mixed models. Predictors of change in FSS over time were examined by adding an interaction term between the baseline variable and time-in-study to the model.ResultsThe patients' mean age was 48.6 years, 47% were Caucasians, and 59% had diffuse cutaneous involvement. The mean disease duration at enrollment was 2.5 years. The FSS was obtained at enrollment and follow-up visits (mean follow-up time = 3.8 years). Average baseline FSS score was 4.7(±0.96). The FSS was relatively stable and did not show a consistent trend for change over time (p = 0.221). In a multivariable model of objective clinical variables, higher Medsger Gastrointestinal (p = 0.006) and Joint (p = 0.024) Severity Indices, and anti-U1-RNP antibodies (p = 0.024) were independent predictors of higher FSS. In the final model, ineffective coping skills captured by higher Illness Behavior Questionnaire scores (p<0.001), higher self-reported pain (p = 0.006), and higher Medsger Gastrointestinal Severity Index (p = 0.009) at enrollment were independent predictors of higher longitudinal FSS scores. Baseline DLco % predicted was the only independent variable that significantly predicted a change in FSS scores over time (p = 0.013), with lower DLco levels predicting an increase in FSS over time.ConclusionsThis study identified potentially modifiable clinical and psychological factors that predict longitudinal fatigue severity in early SSc.

The Effects of Respiratory Muscle Weakness and Pulmonary Involvement on Functional Status, Fatigue and Health Related Quality of Life in Patients With Systemic Sclerosis

“…3,8,10 It has been reported that the greatest impairment in SF-36 subscale scores of SSc patients appeared to be in the physical functioning, general health, and role physical domains whereas mental health was relatively preserved. 9,10 The authors suggested that this unexpected high result in mental summary score was due to psychological adaptation and coping with chronic and disabling underlying conditions.…”

“…1,6 A 0-100 mm breathing visual analog scale was used to measure self-assessment of breathlessness. 1,3,8 Fatigue severity scale was used to measure the impact of excessive fatigue on daily function. 14 The scale includes nine questions related to how fatigue interferes with certain activities, and rates its severity.…”

“…Cardiopulmonary, renal and gastrointestinal system involvement, and organ based complications are frequent, and contribute to excess mortality and early morbidity. [1][2][3][4] Systemic sclerosis affects the lung parenchyma (interstitial pulmonary fibrosis) or pulmonary blood vessels (pulmonary arterial hypertension) or both in the early stage of the disease.…”

“…1,5,6 Symptoms of pulmonary involvement include dyspnea, fatigue, deconditioning, impaired exercise tolerance and in turn, reduced physical, recreational and social activities, and impaired health related quality of life (HRQoL). 1,3,4,[8][9][10] Studies on the contribution of pulmonary involvement and dyspnea to function and quality of life in patients with SSc have reported conflicting results. While some studies showed significant correlations, and advised that Short Form 36 (SF-36) and Health Assessment Questionnaire Disability Index (HAQ-DI) should be included as measurements in scleroderma lung disease, 5,8 some studies did not detect a correlation, and concluded that these measurements are of no value in showing pulmonary involvement in these patients.…”

“…However, research investigating its correlation with pulmonary involvement and dyspnea in scleroderma lung disease is limited. [2][3][4] Furthermore, to the best of our knowledge, no studies have been reported in the literature investigating the effect of respiratory muscle strength on functional status, HRQoL, and fatigue in SSc patients.…”