The persistence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) after SARS-CoV-2 infection: A systematic review and meta-analysis

Highlights:

  • SARS-CoV-2 can trigger Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.
  • 51% of Long COVID-19 patients have Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.
  • Long COVID-19 is a new name for an old disease.

Abstract:

Objectives: Long COVID-19 (LC) patients experience a number of chronic idiopathic symptoms that are highly similar to those of post-viral Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). We have therefore performed a systematic review and meta-analysis to determine the proportion of LC patients that satisfy ME/CFS diagnostic criteria.

Methods: Clinical studies published between January 2020 to May 2023 were identified using the PubMed, Web of Science, Embase and CINAHL databases. Publication inclusion/exclusion criteria were formulated using the global CoCoPop framework. Data were pooled using a random-effects model with a restricted maximum-likelihood estimator. Study quality was assessed using the Joanna Briggs Institute critical assessment tool.

Results: We identified 13 eligible studies that reported a total of 1,973 LC patients. Our meta-analysis indicated that 51% (95% CI, 42%-60%) of LC patients satisfied ME/CFS diagnostic criteria with fatigue, sleep disruption, and muscle/joint pain being the most common symptoms. Importantly, LC patients also experienced the ME/CFS hallmark symptom, post-exertional malaise.

Conclusions: Our study not only demonstrates that LC patients exhibit similar symptom clusters to ME/CFS, but that approximately half of LC patients satisfy a diagnosis of ME/CFS. Our findings suggest that current ME/CFS criteria could be adapted to the identification of a subset of LC patients that may facilitate the standardized diagnosis, management and the recruitment for clinical studies in the future.

Source: Ankush Dehlia, Mark A. Guthridge. The persistence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) after SARS-CoV-2 infection: A systematic review and meta-analysis. Journal of Infection, 2024, 106297, ISSN 0163-4453, https://doi.org/10.1016/j.jinf.2024.106297.
https://www.sciencedirect.com/science/article/pii/S0163445324002317 (Full text)

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the biology of a neglected disease

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic, debilitating disease characterised by a wide range of symptoms that severely impact all aspects of life. Despite its significant prevalence, ME/CFS remains one of the most understudied and misunderstood conditions in modern medicine. ME/CFS lacks standardised diagnostic criteria owing to variations in both inclusion and exclusion criteria across different diagnostic guidelines, and furthermore, there are currently no effective treatments available.

Moving beyond the traditional fragmented perspectives that have limited our understanding and management of the disease, our analysis of current information on ME/CFS represents a significant paradigm shift by synthesising the disease’s multifactorial origins into a cohesive model. We discuss how ME/CFS emerges from an intricate web of genetic vulnerabilities and environmental triggers, notably viral infections, leading to a complex series of pathological responses including immune dysregulation, chronic inflammation, gut dysbiosis, and metabolic disturbances.

This comprehensive model not only advances our understanding of ME/CFS’s pathophysiology but also opens new avenues for research and potential therapeutic strategies. By integrating these disparate elements, our work emphasises the necessity of a holistic approach to diagnosing, researching, and treating ME/CFS, urging the scientific community to reconsider the disease’s complexity and the multifaceted approach required for its study and management.

Source: Arron HE, Marsh BD, Kell DB, Khan MA, Jaeger BR, Pretorius E. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the biology of a neglected disease. Front Immunol. 2024 Jun 3;15:1386607. doi: 10.3389/fimmu.2024.1386607. PMID: 38887284; PMCID: PMC11180809. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11180809/ (Full text)

Epidemiology of Myalgic Encephalomyelitis among individuals with self-reported Chronic Fatigue Syndrome in British Columbia, Canada, and their health-related quality of life

Abstract:

Background: There is no accurate data on the epidemiology of Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS) in Canada. The aims of the study were to describe the epidemiology of confirmed ME/CFS cases and their health-related quality of life (HRQoL).

Methods: This is a cross-sectional study with British Columbia Generations Project (BCGP) participants who self-reported having CFS and population-based controls with no fatiguing illness. Participants completed the Symptoms Assessment Questionnaire, RAND 36-item Health Survey, and Phenotyping Questionnaire Short-form. These assessments enabled the identification and characterization of confirmed cases of ME/CFS. Those with self-reported diagnoses who did not meet study diagnosis of ME/CFS were subcategorized as non-ME/CFS cases.

Results: We included 187 participants, 45.5% (n=85) self-reported cases and 54.5% (n=102) controls; 34% (n=29) of those who self-reported ME/CFS fulfilled diagnostic criteria for ME/CFS. The population prevalence rates were 1.1% and 0.4% for self-reported and confirmed ME/CFS cases respectively. Participants displayed significantly lower scores in all eight SF-36 domains compared to the other groups. Mental component scores were similar between ME/CFS and non-ME/CFS groups. The main risk factor for low HRQoL scores was fatigue severity (β = -0.6, p<0.001 for physical health; β = -0.7, p<0.001 for mental health).

Conclusions: The majority of self-reported cases do not meet diagnostic criteria for ME/CFS, suggesting that self-reported CFS may not be a reliable indicator for a true ME/CFS diagnosis. HRQoL indicators were consistently lower in ME/CFS and non-ME/CFS cases compared to controls, with ME/CFS cases having lower scores in most domains. Having higher symptom severity scores and perceived poorer health were the significant affecting factors of lower HRQoL. Although self-report can be used as screening to identify cases in populations, we suggest studies of ME/CFS should include appropriate medically confirmed clinical diagnosis for validity. Further large-scale population-based studies with simultaneous medical assessment are suggested to further characterize validity parameters of self-reported diagnosis.

Source:Enkhzaya Chuluunbaatar-LussierMelody TsaiTravis BoulterCarola MunozKathleen KerrLuis Nacul. Epidemiology of Myalgic Encephalomyelitis among individuals with self-reported Chronic Fatigue Syndrome in British Columbia, Canada, and their health-related quality of life. 

Frequency and characteristics of chronic fatigue syndrome in multiple sclerosis patients at a university hospital in Eastern Saudi Arabia

Abstract:

BACKGROUND: Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disease that affects various parts of the central nervous system. Fatigue, a common symptom, transient, prolonged, or chronic experienced by individuals with MS, can significantly impact daily functioning. It can be associated with underlying pathological processes or can have an idiopathic cause, such as chronic fatigue syndrome (CFS). The study aimed to assess the presence and etiology of fatigue in MS patients and its relationship with CFS.

MATERIALS AND METHODS: This cross-sectional study was conducted in the Eastern Province of Saudi Arabia. Data were collected using a questionnaire from a sample of 225 MS patients receiving care at our university hospital. The questionnaire included the Centers for Disease Control and Prevention (CDC) criteria for diagnosing CFS and the Expanded Disability Status Scale to evaluate fatigue in MS patients.

RESULTS: Of the total of 225 MS patients who participated in this study, 87.1% were diagnosed with relapsing-remitting MS, 6.7% with primary progressive MS, 3.6% with clinically isolated syndrome, and 2.7% with secondary progressive MS. About 53% had experienced fatigue that persisted for over 6 months. Analysis of CFS diagnosis revealed that 7.3% of patients met both CDC criteria and self-reported answers while 17.5% reported having CFS despite not meeting the CDC criteria. These findings highlight a significant lack of agreement between patient-reported diagnoses and established criteria, indicating poor agreement (P = 0.028).

CONCLUSION: The study found an association between CFS and MS, and a significant impact on daily functioning. The study revealed lack of agreement between patient-reported diagnoses and established criteria for CFS. This emphasizes the need for a standardized approach to diagnosis and evaluation of fatigue in MS patients.

Source: AlAmri, Abdullah S.; AlShamrani, Foziah J.; AlMohish, Noor M.; Zafar, Azra S.; Alnaaim, Saud A.1; Alazman, Hatem A.; Al-Ghanimi, Ibrahim A.2; AlNahdi, Abdullah A.; AlDawsari, Fahad A.; AlMatrafi, Shahad B.3; Alzahrani, Ghaida R.3; Alnamlah, Muna S.; Alkhalifa, Rawan A.. Frequency and characteristics of chronic fatigue syndrome in multiple sclerosis patients at a university hospital in Eastern Saudi Arabia. Journal of Family and Community Medicine 31(1):p 63-70, Jan–Mar 2024. | DOI: 10.4103/jfcm.jfcm_73_23 https://journals.lww.com/jfcm/fulltext/2024/31010/frequency_and_characteristics_of_chronic_fatigue.9.aspx (Full text)

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and fibromyalgia: PR3-versus MPO-ANCA-associated vasculitis, an exploratory cross-sectional study

Summary:

Background: Persistent fatigue is a common complaint in ANCA-vasculitis (AAV) patients and has a profound impact on patient’s quality of life. The symptoms associated with this fatigue mirror those found in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and fibromyalgia. Etiologic and pathophysiologic differences exist between PR3- and MPO-ANCA disease, yet differences in their fatigue manifestations have not been well researched. We compared fatigue and its associations in healthy controls, AAV patients and fibromyalgia controls.

Methods: The Canadian consensus criteria were used for ME/CFS diagnosis, and American College of Rheumatology criteria for fibromyalgia diagnosis. Factors such as cognitive failure, depression, anxiety, and sleep disturbances were assessed by patient reported questionnaires. Clinical factors such as BVAS, vasculitis damage index, CRP and BMI were also collected.

Findings: Our AAV cohort comprised 52 patients, with a mean age of 44.7 (20–79), 57% (30/52) of the patients were female. We found 51.9% (27/52) of patients fulfilled the diagnostic criteria for ME/CFS, with 37% (10/27) of those having comorbid fibromyalgia. Rates of fatigue were higher in MPO-ANCA patients, than in PR3-ANCA patients, and their symptoms were more similar to the fibromyalgia controls. Fatigue in PR3-ANCA patients was related to inflammatory markers. These differences may be due to the varied pathophysiology of the PR3- and MPO-ANCA serotypes.

Interpretation: A large proportion of AAV patients suffer from debilitating fatigue consequential enough to meet the diagnostic criteria for ME/CFS. Fatigue associations were not the same between PR3- and MPO-ANCA patients, suggesting that the underlying mechanisms may be different. Future studies should consider ANCA serotype, as further research may inform different clinical treatment strategies for AAV patients suffering from ME/CFS.

Source: Charmaine van Eeden, Naima Mohazab, Desiree Redmond, Elaine Yacyshyn, Alison Clifford, Anthony S. Russell, Mohammed S. Osman, and Jan Willem Cohen Tervaer. Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and fibromyalgia: PR3-versus MPO-ANCA-associated vasculitis, an exploratory cross-sectional study. The Lancet Regional Health – Americas 2023;20: 100460.  https://www.thelancet.com/journals/lanam/article/PIIS2667-193X(23)00034-0/fulltext# (Full text)

Orthostatic intolerance and neurocognitive impairment in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Abstract:

Objectives: The Institute of Medicine (IOM 2015. Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington: The National Academies Press) suggested new criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), which requires an endorsement of either neurocognitive impairment or orthostatic intolerance (OI) in addition to other core symptoms. While some research supports the inclusion of OI as a core symptom, others argue that overlap with neurocognitive impairment does not justify the either/or option. The current study assessed methods of operationalizing OI using items from the DePaul Symptom Questionnaire (DSQ-1 and -2) as a part of the IOM criteria. Evaluating the relationship between OI and neurocognitive symptoms may lead to a better understanding of diagnostic criteria for ME/CFS.

Methods: Two-hundred and forty-two participants completed the DSQ. We examined how many participants met the IOM criteria while endorsing different frequencies and severities of various OI symptoms.

Results: Neurocognitive impairment was reported by 93.4% of respondents. OI without concurrent neurocognitive symptoms only allowed for an additional 1.7–4.5% of participants to meet IOM criteria.

Conclusions: Neurocognitive symptoms and OI overlap in ME/CFS, and our results do not support the IOM’s inclusion of neurocognitive impairment and OI as interchangeable symptoms. Furthermore, our findings highlight the need for a uniform method of defining and measuring OI via self-report in order to accurately study OI as a symptom of ME/CFS.

Source: Gaglio, Caroline L., Islam, Mohammed F., Cotler, Joseph and Jason, Leonard A.. “Orthostatic intolerance and neurocognitive impairment in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)” Epidemiologic Methods, vol. 11, no. 1, 2022, pp. 20210033. https://doi.org/10.1515/em-2021-0033

Evaluating case diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): toward an empirical case definition

Abstract:

Purpose: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is an illness characterized by a variety of symptoms including post-exertional malaise, unrefreshing sleep, and cognitive impairment. A variety of case definitions (e.g., the Canadian Consensus Criteria (CCC), the Myalgic Encephalomyelitis International Consensus Criteria (ME-ICC), and the Institute of Medicine (IOM) criteria) have been used to diagnose patients. However, these case definitions are consensus-based rather than empirical.

Materials and methods: The aim of the current study was to evaluate the validity of the aforementioned case definitions by factor analyzing a large, international sample (N = 2308) of ME/CFS symptom data. We performed primary and secondary exploratory factor analyses on the DePaul Symptom Questionnaire’s 54-item symptom inventory. These results were compared to the CCC, the ME-ICC, and the IOM criteria.

Results: We identified seven symptom domains, including post-exertional malaise, cognitive dysfunction, and sleep dysfunction. Contrary to many existing case criteria, our analyses did not identify pain as an independent factor.

Conclusions: Although our results implicate a factor solution that best supports the CCC, revisions to the criteria are recommended. Implications for rehabilitation: ME/CFS is a chronic illness with no consensus regarding case diagnostic criteria, which creates difficulty for patients seeking assistance and disability benefits. The current study compared three commonly used case definitions for ME/CFS by factor analyzing symptomological data from an international sample of patients. Our results suggest three primary and four secondary symptom domains which differed from all three case definitions. These findings could help reduce barriers to care for those disabled with ME/CFS by guiding the development of an empirically-based case definition.

Source: Conroy KE, Islam MF, Jason LA. Evaluating case diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): toward an empirical case definition. Disabil Rehabil. 2022 Mar 2:1-8. doi: 10.1080/09638288.2022.2043462. Epub ahead of print. PMID: 35236205. https://pubmed.ncbi.nlm.nih.gov/35236205/

Clinical Profile and Aspects of Differential Diagnosis in Patients with ME/CFS from Latvia

Abstract:

Background and objectives: There is still an uncertainty regarding the clinical symptomatology and the diagnostic criteria in terms of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), as different diagnostic criteria exist. Our aim is to identify the core symptoms of ME/CFS in the outpatient setting in Riga; to distinguish symptoms in patients with ME/CFS and those with symptoms of fatigue; and to investigate patient thoughts on the onset, symptoms, treatment and effect of ME/CFS.

Materials and methods: Total of 65 Caucasian patients from an ambulatory care setting were included in the study. Questionnaires, specialist evaluation of the patients and visual analogue scale (VAS) measurements were used to objectify the findings.

Results: The study showed that ME/CFS with comorbidities is associated with a more severe disease. A negative correlation was found regarding an increase in age and number of current symptoms, as well as an increase in VAS score and the duration of fatigue and age in the ME/CFS without comorbidities group.

Conclusions: Comorbidities tend to present with a more severe course of ME/CFS. Fatigue, myalgia, arthralgia and sleep disturbances tend to be more prevalent in the ME/CFS patients compared to the non-ME/CFS patients. VAS score has a tendency to decrease with age and duration of fatigue. Nonsteroidal anti-inflammatory drugs are the most commonly used pharmacological drug class that reduces ME/CFS symptoms.

Source: Krumina A, Vecvagare K, Svirskis S, Gravelsina S, Nora-Krukle Z, Gintere S, Murovska M. Clinical Profile and Aspects of Differential Diagnosis in Patients with ME/CFS from Latvia. Medicina (Kaunas). 2021 Sep 11;57(9):958. doi: 10.3390/medicina57090958. PMID: 34577881. https://pubmed.ncbi.nlm.nih.gov/34577881/

Chronic Fatigue Syndrome: From Chronic Fatigue to More Specific Syndromes

Abstract:

In the last decade, a group of chronic disorders associated with fatigue (CDAF) emerged as the leading cause of chronic fatigue, chronic pain, and functional impairment, all of which have been often labeled in clinical practice as chronic fatigue syndrome (CFS) or fibromyalgia. While these chronic disorders arise from various pathophysiologic mechanisms, a shared autoimmune or immune-mediated etiology could shift the focus from symptomatic treatment of fatigue and pain to targeted immunomodulatory and biological therapy.

A clinical paradigm shift is necessary to reevaluate CFS and fibromyalgia diagnoses and its relationship to the CDAF entities, which would ultimately lead to a change in diagnostic and therapeutic algorithm for patients with chronic fatigue and chronic pain. Rather than uniformly apply the diagnoses of CFS or fibromyalgia to any patient presenting with unexplained chronic fatigue or chronic pain, it may be more beneficial and therapeutically effective to stratify these patients into more specific diagnoses in the CDAF group.

Source: Blitshteyn S, Chopra P. Chronic Fatigue Syndrome: From Chronic Fatigue to More Specific Syndromes. Eur Neurol. 2018 Oct 4;80(1-2):73-77. doi: 10.1159/000493531. [Epub ahead of print]  https://www.ncbi.nlm.nih.gov/pubmed/30286454

Diagnosis and Treatment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

We present here the Japanese clinical diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) that were proposed in 2016 by the Japanese Ministry of Health, Labour and Welfare study group. The clinical diagnosis criteria of ME/CFS were created to be used by healthcare agencies in charge of primary care practice. We also explain the current prognosis in ME/CFS and medical treatments used in major medical institutions in Japan.

Source: Kuratsune H. Diagnosis and Treatment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Brain Nerve. 2018 Jan;70(1):11-18. doi: 10.11477/mf.1416200944.[Article in Japanese] https://www.ncbi.nlm.nih.gov/pubmed/29348370