Fatigue significantly contributes to impaired well-being in MS: Study
Nearly 50% of patients report it, were found to have lower quality of life
Nearly 50% of people with multiple sclerosis (MS) report pronounced fatigue, which has a significantly negative effect on their well-being, a new study from Finland has found.
In an analysis of data from more than 500 patients from the Finnish MS registry, individuals with self-perceived fatigue were more likely to also report mood and cognitive issues, and to have a poorer quality of life, according to the researchers. These patients also reported a greater impact of their disease on physical and psychological functioning.
“We observed that fatigue … is related to a more pronounced negative impact of the disease. … [It] alone … and together with physical disability … explain lower [quality of life],” the team wrote, also noting “a growing need to implement patient engagement options … to combine objective disease data to subjective patient-centered outcomes.”
Their study, “Evaluation of patient-perceived fatigue in multiple sclerosis utilizing the Finnish MS registry,” was published in the Multiple Sclerosis Journal – Experimental, Translational and Clinical.
Pronounced fatigue reported by 47% of study respondents
Fatigue has been reported as one of the most debilitating symptoms of MS, affecting as many as 80% of patients. It’s characterized by an overwhelming feeling of tiredness, exhaustion, or energy loss that significantly impacts mental health and cognition, the ability to work or engage in physical activities, and quality of life.
In MS, this symptom arises primarily from damage to the myelin sheath, the fatty layer around nerve cells, caused by the underlying inflammation that drives the disease, research has shown. Additional factors, such as other MS symptoms, emotional stress, and medication side effects, can further worsen the problem.
Still, this is an “invisible symptom [that] remains often underdiagnosed,” the researchers wrote, highlighting the need for its early diagnosis to prevent negative impacts on patients.
To that end, a team of researchers in Finland now set out to examine how common this symptom is among MS patients — and how it impacts other disease outcomes. The researchers used data from the Finnish MS registry, which was launched in 2014 to follow the outcomes of people in the country with the neurodegenerative disease. An interface called MyMS, added in 2017, also collects data on a number of patient-reported outcomes using validated questionnaires.
Fatigue levels were assessed using the Fatigue Severity Scale, or FSS, which consists of nine statements related to the symptom with responses of 1-7. A one indicates respondents strongly disagree, while seven means they strongly agree.
A total of 512 patients reported their fatigue levels using the FSS at some point through January 2023, and were included in the analyses. Among them, 47% reported pronounced fatigue, defined as an FSS score of five or greater, at some point during their follow-up. Conversely, 45% reported no symptoms, with scores of four or lower. The remaining 8% had borderline fatigue, with scores between four and five.
[This is an] invisible symptom [that] remains often underdiagnosed.
The researchers noted that “our findings indicate that fatigue is a symptom of MS that may present early in the disease trajectory.”
Researchers suggest use of 2 different measures for symptom screening
When looking at people with and without self-reported fatigue, significant differences were observed in other patient-reported outcome measures. Specifically, fatigue correlated significantly with worse cognitive and mood issues, lower quality of life, and a greater impact of MS on day-to-day activities.
Importantly, according to the researchers, the analyses also demonstrated the critical impact of this symptom on quality of life and perceived disease impact for MS patients. When multiple factors were considered, fatigue, together with disability, explained both the reduced quality of life and the negative impact of the disease, per the team.
This suggests that fatigue independently contributes to impaired well-being, even when other factors are considered.
Additionally, the researchers compared FSS scores with those of another measure of patient-reported fatigue, called the Fatigue Scale for Motor and Cognitive Functions (FSMC), which assesses both motor and cognitive aspects of this symptom.
The FSMC scores confirmed that the two scales correlated generally well, with higher FSS scores being significantly associated with worse total, cognitive, and motor fatigue on FSMC.
Still, a small proportion of patients who did not report problems on the FSS were found to have severe symptoms on the FSMC. That finding suggests that the FSMC may better capture more nuanced aspects of cognitive and mental fatigue that might be underdiagnosed with the FSS alone, the researchers noted.
“As an invisible and debilitating symptom fatigue should be evaluated systematically,” the researchers concluded. “In the screening, it is important to recognize the characteristics of the different scales. Whereas the FSS may serve as an overall screen, the FSMC may help to identify aspects of cognitive and motor fatigue separately.”
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