Session Type: Poster Session C
Session Time: 9:00AM-11:00AM
Background/Purpose: Fatigue is a major complaint in autoimmune diseases including primary Sjögren’s syndrome (pSS). For many pSS patients, fatigue is their most dominant and disabling symptom. In a conceptual framework1, fatigue is defined as a self-reported symptom derived from 2 attributes: 1. performance fatigability, an objective decline in performance, and, 2. changes in anticipated capabilities of the performer (modulated by factors such as pain and depression). In multiple sclerosis, studies have already demonstrated a relation between performance decline and self-reported fatigue2. So far, no data are available on performance fatigability in pSS. Our objectives were to assess whether performance fatigability is affected in pSS, and to explore its relations with self-reported fatigue, pain, and depression.
Methods: Thirty-nine pSS patients (fulfilling the 2016 ACR-EULAR criteria; 5 males, age 27-65 years) and 27 healthy control participants (5 males, age 27-65 years) were included in the study. To assess performance fatigability, participants generated a sustained (124 s) maximal voluntary contraction (MVC) with the index finger abductor muscle; force was recorded using force-transducers. During the contraction, voluntary muscle activation was indexed by electrical stimulation of the ulnar nerve (for details:2). Self-reported fatigue was quantified using questionnaires: Fatigue Severity Scale (FSS) and, in patients only, Modified Fatigue Impact Scale (MFIS). The MFIS distinguishes a physical and cognitive domain. Pain and depression were measured using the EULAR Sjögren’s Syndrome Patient Reported Index (ESSPRI pain) and Hospital Anxiety and Depression scale (HADS), respectively. Differences between pSS and controls were assessed using ANOVAs or Mann-Whitney U tests. Linear regression analysis was performed to determine which factors could explain increased levels of self-reported fatigue in pSS.
Results: With regard to performance fatigability, residual force after the sustained MVC did not differ between groups. However, voluntary muscle activation was reduced in pSS (p = 0.029, Fig. 1). Self-reported fatigue was significantly higher in pSS than controls (FSS median: 4.8 vs. 2.3, p< 0.001), and 67% of the pSS patients reported significant fatigue (FSS >4) versus none of the controls. In pSS, 47% of the variance in MFIS physical could be explained by residual force after the sustained MVC, and partly by pain and depression (p< 0.001, Fig. 2). FSS and MFIS cognitive could be best explained by HADS depression scores.
Conclusion: Performance fatigability in pSS was compromised by reduced voluntary muscle activation. Furthermore, self-reported fatigue in pSS was related to objectively measured performance decline (i.e. performance fatigability), as well as symptoms of pain and depression. These findings indicate that performance fatigability should be considered when investigating fatigue, and may serve as an important outcome measure for future clinical trials.
1. Enoka et al., Med Sci Sports Exerc. 2016 Nov 48(11):2228-38.
2. Steens et al., Neurorehabil Neural Repair. 2012 Jan 26(1):48-57.
Figure 1. Measures of performance fatigability. A) Residual force following the sustained maximal voluntary contraction, expressed as a percentage of maximal force (MVC). B) Voluntary muscle activation (mean across 7 time-points) during the sustained maximal voluntary contraction. Voluntary muscle activation of 100% indicates that the muscle is firing at its maximal capacity, and that central nervous system drive is optimal. P-values are shown in both graphs.
Figure 2. Relationship between self-reported fatigue (MFIS physical) and performance fatigability, pain, and depression. Predicted MFIS physical score is based on results of the multivariable regression. Standardized beta’s and p-values of the model predictors are shown on the right. MFIS = Modified Fatigue Impact Scale; HADS = Hospital Anxiety and Depression Scale.
To cite this abstract in AMA style:Prak R, Arends S, van Zuiden G, Kroese F, Bootsma H, Zijdewind I. Self-reported Fatigue in Patients with Primary Sjögren’s Syndrome Is Associated with an Objective Decline in Physical Performance and Symptoms of Pain and Depression [abstract]. Arthritis Rheumatol. 2020; 72 (suppl 10). https://acrabstracts.org/abstract/self-reported-fatigue-in-patients-with-primary-sjogrens-syndrome-is-associated-with-an-objective-decline-in-physical-performance-and-symptoms-of-pain-and-depression/. Accessed October 16, 2021.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/self-reported-fatigue-in-patients-with-primary-sjogrens-syndrome-is-associated-with-an-objective-decline-in-physical-performance-and-symptoms-of-pain-and-depression/