Risk factors for chronic fatigue syndrome/myalgic encephalomyelitis: a systematic scoping review of multiple predictor studies

Abstract:

BACKGROUND: The aetiology of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is still unknown. The identification of risk factors for CFS/ME is of great importance to practitioners.

METHOD: A systematic scoping review was conducted to locate studies that analysed risk factors for CFS/ME using multiple predictors. We searched for published and unpublished literature in 11 electronic databases, reference lists of retrieved articles and guideline stakeholder submissions in conjunction with the development of a forthcoming national UK guideline. Risk factors and findings were extracted in a concise tabular overview and studies synthesized narratively.

RESULTS: Eleven studies were identified that met inclusion criteria: two case-control studies, four cohort studies, three studies combining a cohort with a case-control study design, one case-control and twin study and one cross-sectional survey. The studies looked at a variety of demographic, medical, psychological, social and environmental factors to predict the development of CFS/ME. The existing body of evidence is characterized by factors that were analysed in several studies but without replication of a significant association in more than two studies, and by studies demonstrating significant associations of specific factors that were not assessed in other studies. None of the identified factors appear suitable for the timely identification of patients at risk of developing CFS/ME within clinical practice.

CONCLUSIONS: Various potential risk factors for the development of CFS/ME have been assessed but definitive evidence that appears meaningful for clinicians is lacking.

 

Source: Hempel S, Chambers D, Bagnall AM, Forbes C. Risk factors for chronic fatigue syndrome/myalgic encephalomyelitis: a systematic scoping review of multiple predictor studies. Psychol Med. 2008 Jul;38(7):915-26. Epub 2007 Sep 25. https://www.ncbi.nlm.nih.gov/pubmed/17892624

 

Chronic fatigue syndrome is associated with chronic enterovirus infection of the stomach

Abstract:

BACKGROUND AND AIMS: The aetiology for chronic fatigue syndrome (CFS) remains elusive although enteroviruses have been implicated as one of the causes by a number of studies. Since most CFS patients have persistent or intermittent gastrointestinal (GI) symptoms, the presence of viral capsid protein 1 (VP1), enterovirus (EV) RNA and culturable virus in the stomach biopsy specimens of patients with CFS was evaluated.

METHODS: 165 consecutive patients with CFS underwent upper GI endoscopies and antrum biopsies. Immunoperoxidase staining was performed using EV-specific monoclonal antibody (mAb) or a control mAb specific for cytomegalovirus (CMV). RT-PCR ELISA was performed on RNA extracted from paraffin sections or samples preserved in RNA later. Biopsies from normal stomach and other gastric diseases served as controls. 75 samples were cultured for EV.

RESULTS: 135/165 (82%) biopsies stained positive for VP1 within parietal cells, whereas 7/34 (20%) of the controls stained positive (p< or =0.001). CMV mAb failed to stain any of the biopsy specimens. Biopsies taken from six patients at the onset of the CFS/abdominal symptoms, and 2-8 years later showed positive staining in the paired specimens. EV RNA was detected in 9/24 (37%) paraffin-embedded biopsy samples; 1/21 controls had detectable EV RNA (p<0.01); 1/3 patients had detectable EV RNA from two samples taken 4 years apart; 5 patient samples showed transient growth of non-cytopathic enteroviruses.

CONCLUSION: Enterovirus VP1, RNA and non-cytopathic viruses were detected in the stomach biopsy specimens of CFS patients with chronic abdominal complaints. A significant subset of CFS patients may have a chronic, disseminated, non-cytolytic form of enteroviral infection, which could be diagnosed by stomach biopsy.

Comment in: Enterovirus infection of the stomach in chronic fatigue syndrome/myalgic encephalomyelitis. [J Clin Pathol. 2008]

 

Source: Chia JK, Chia AY. Chronic fatigue syndrome is associated with chronic enterovirus infection of the stomach. J Clin Pathol. 2008 Jan;61(1):43-8. Epub 2007 Sep 13. https://www.ncbi.nlm.nih.gov/pubmed/17872383

 

NICE behaviour: ME guideline is unworkable

Comment on: Diagnosis and management of chronic fatigue syndrome or myalgic encephalomyelitis (or encephalopathy): summary of NICE guidance. [BMJ. 2007]

 

The National Institute for Health and Clinical Excellence (NICE) recommends that everyone with mild or moderate myalgic encephalopathy/chronic fatigue syndrome (ME/CFS) should be offered a course of either cognitive behaviour therapy (CBT) or graded exercise therapy (GET).1

This is despite published evidence remaining weak (especially for group CBT) and inconsistent 2. Patient evidence submitted to the chief medical officer’s report concluded that CBT produced “no change” in 67% of cases and made the condition “worse” in 26% of cases.3 Around 50% of respondents reported that inappropriate exercise therapy had also made their condition “worse.”3

When the NICE estimate on prevalence is used this controversial recommendation will affect some 200 000 people. A one to one course of CBT covering 12 to 16 sessions will cost well over £1500. The cost of a professionally supervised exercise therapy programme is also likely to be substantial.

So where is around £300 million of new money going to come from at a time when very limited funding for some of the newly established NHS clinical services for people with ME/CFS is now being cut?4 And where are all the therapists going to come from? Those already in post often cannot even cope with their current workload.

These are important questions that I raised at a NICE implementation and planning meeting in October 2006—but nobody from NICE could provide a convincing answer. These recommendations are going to be of no value whatsoever to many people with ME/CFS. They are also going to be impossible to implement owing to a lack of both funding and human resources.

You can read the rest of this comment here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1976494/

 

Source: Shepherd CB. NICE behaviour: ME guideline is unworkable. BMJ. 2007 Sep 15;335(7619):528. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1976494/ (Full article)

 

Neuroaetiology of chronic fatigue syndrome: an overview

Abstract:

Chronic fatigue syndrome (CFS) is now recognized as a medial disorder. In contrast to recent related reports, the present review focuses primarily on aetiological aspects of CFS. Four major hypotheses are reviewed. (1) Although CFS is often associated with viral infection, the presence of viruses has as yet not consistently been detected. (2) It is not clear whether anomalies of the HPA axis often observed in CFS, are cause or the consequences of the disorder. (3) Immune dysfunction as the cause of CFS is thus far the weakest hypothesis. (4) The psychiatric and psychosocial hypothesis denies the existence of CFS as a disease entity. Accordingly, the fatigue symptoms are assumed to be the consequence of other (somatic) diseases. Other possible causes of CFS are oxidative stress and genetic predisposition. In CFS cognitive behavioural therapy is most commonly used. This therapy, however, appears to be ineffective in many patients. The suggested causes of CFS and the divergent reactions to therapy may be explained by the lack of recognition of subgroups. Identification of subtypes may lead to more effective therapeutic interventions.

 

Source: Sanders P, Korf J. Neuroaetiology of chronic fatigue syndrome: an overview. World J Biol Psychiatry. 2008;9(3):165-71. https://www.ncbi.nlm.nih.gov/pubmed/17853290

 

Higher heart rate and reduced heart rate variability persist during sleep in chronic fatigue syndrome: a population-based study

Abstract:

Autonomic nervous system (ANS) dysfunction has been suggested in patients with chronic fatigue syndrome (CFS). In this study, we sought to determine whether increased heart rate (HR) and reduced heart rate variability (HRV) parameters observed in CFS patients during wakefulness persist during sleep. To this end, we compared heart rate (HR) and HRV as indicators of ANS function in CFS subjects and non-fatigued (NF) controls in a population-based, case-control study.

Thirty subjects with CFS and 38 NF controls, matched for age-, sex- and body mass index, were eligible for analysis. Main outcome measures included mean RR interval (RRI), HR, and HRV parameters derived from overnight ECG. Plasma aldosterone and norepinephrine levels, medicines with cardiovascular effect, and reported physical activity were examined as covariates. General Linear Models were used to assess significance of associations and adjust for potential confounders.

Compared to controls, CFS cases had significantly higher mean HR (71.4 vs 64.8 bpm), with a shorter mean RRI [840.4 (85.3) vs 925.4(97.8) ms] (p<0.0004, each), and reduced low frequency (LF), very low frequency (VLF), and total power (TP) of HRV (p<0.02, all). CFS cases had significantly lower plasma aldosterone (p<0.05), and tended to have higher plasma norepinephrine levels. HR correlated weakly with plasma norepinephrine (r=0.23, p=0.05) and moderately with vitality and fatigue scores (r=-0.49 and 0.46, respectively, p<0.0001). Limitation in moderate physical activity was strongly associated with increased HR and decreased HRV. Nevertheless, among 42 subjects with similar physical activity limitations, CFS cases still had higher HR (71.8 bpm) than respective controls (64.9 bpm), p=0.023, suggesting that reduced physical activity could not fully explain CFS-associated differences in HR and HRV. After adjusting for potential confounders case-control differences in HR and TP remained significant (p<0.05).

CONCLUSION: The presence of increased HR and reduced HRV in CFS during sleep coupled with higher norepinephrine levels and lower plasma aldosterone suggest a state of sympathetic ANS predominance and neuroendocrine alterations. Future research on the underlying pathophysiologic mechanisms of the association is needed.

 

Source: Boneva RS, Decker MJ, Maloney EM, Lin JM, Jones JF, Helgason HG, Heim CM, Rye DB, Reeves WC. Higher heart rate and reduced heart rate variability persist during sleep in chronic fatigue syndrome: a population-based study. Auton Neurosci. 2007 Dec 30;137(1-2):94-101. Epub 2007 Sep 12. https://www.ncbi.nlm.nih.gov/pubmed/17851136

 

Open-label study of s-citalopram therapy of chronic fatigue syndrome and co-morbid major depressive disorder

Abstract:

OBJECTIVE: Chronic fatigue syndrome (CFS) is a debilitating disorder with prominent symptoms of malaise, fatigue, myalgia, arthralgia, and impaired concentration. The symptoms of CFS may often overlap those of Major Depressive Disorder (MDD). Treatment of CFS has generally been disappointing. We hypothesized that s-citalopram therapy may improve the symptoms of both disorders in CFS patients with co-morbid depression.

METHODS: 16 patients received s-citalopram 10 mg to 20 mg daily for up to 12 weeks. Outcome measures of CFS included the Chalder Fatigue Questionnaire (CFQ), the multi-dimensional Fatigue Impact Scale (FIS), the CFS symptom rating (CFS-SR) 100 mm visual analogue scale, and the clinical global impressions severity (CGI/S) and change (CGI/C) ratings. Secondary outcomes of MDD included the Hamilton Depression Rating (HAM-D), Beck Depression Inventory (BDI), and the CGI/S and CGI/C ratings of MDD.

RESULTS: We observed reductions in the mean CFQ score (p<0.0005), FIS score (p<0.0005), and CGI/S (p<0.0005) and CGI/C (p<0.0005) ratings over time. There was a significant improvement in 5 of the 8 CFS-SR symptoms: post-exertion malaise (p=0.001), headaches (p<0.0005), un-refreshing sleep (p<0.0005), and impaired memory and concentration (p<0.0005). There was also a reduction in mean HAM-D (p<0.0005), BDI (p<0.0005), CGI/S (p=0.001) and CGI/C (p<0.0005) ratings of MDD.

LIMITATIONS: The sample size was limited and the study design was not double-blind or placebo controlled.

CONCLUSION: We observed a significant reduction in both CFS and co-morbid MDD symptom severity ratings, and improvement in 5 of 8 core somatic symptoms of CFS during s-citalopram therapy.

 

Source: Amsterdam JD, Shults J, Rutherford N. Open-label study of s-citalopram therapy of chronic fatigue syndrome and co-morbid major depressive disorder. Prog Neuropsychopharmacol Biol Psychiatry. 2008 Jan 1;32(1):100-6. Epub 2007 Aug 3. https://www.ncbi.nlm.nih.gov/pubmed/17804135

 

Combined dexamethasone/corticotropin-releasing factor test in chronic fatigue syndrome

Abstract:

BACKGROUND: Studies of hypothalamic-pituitary-adrenal (HPA) axis function in chronic fatigue syndrome (CFS) point to hypofunction, although there are negative reports. Suggested mechanisms include a reduced hypothalamic or supra-hypothalamic stimulus to the HPA axis and enhanced sensitivity to the negative feedback of glucocorticoids. The aim of the current study was to investigate HPA axis function in CFS with the dexamethasone/corticotropin-releasing factor (Dex/CRF) test, in analogy with research in affective disorders.

METHOD: Thirty-four well-characterized female CFS patients and 25 healthy control subjects participated in the low-dose Dex/CRF test. Current major depressive episode was an exclusion criterion. History of early-life stress (ELS) was assessed with the Structured Trauma Interview.

RESULTS: Salivary cortisol responses after 0.5 mg Dex were lower in CFS patients than in controls (before 100 microg CRF, p=0.038; after 100 microg CRF, p=0.015). A secondary analysis revealed an influence of early-life stress and of oestrogen intake. After removal of the 10 participants who were taking an oral oestrogen, patients without a history of ELS showed lower cortisol responses than patients with ELS and controls (before CRF, p=0.005; after CRF, p=0.008).

CONCLUSIONS: CFS is globally associated with reduced cortisol responses in the combined low-dose Dex/CRF test, but this effect is only clearly present in CFS patients without a history of ELS. This study provides further support for an enhanced glucocorticoid negative feedback and/or a reduced central HPA axis drive in CFS. Furthermore, it demonstrates that ELS is an important variable to consider in CFS research.

 

Source: Van Den Eede F, Moorkens G, Hulstijn W, Van Houdenhove B, Cosyns P, Sabbe BG, Claes SJ. Combined dexamethasone/corticotropin-releasing factor test in chronic fatigue syndrome. Psychol Med. 2008 Jul;38(7):963-73. Epub 2007 Sep 6. https://www.ncbi.nlm.nih.gov/pubmed/17803834

 

The chronic fatigue syndrome: a comparative pathway analysis

Abstract:

In this paper, we introduce a method to detect pathological pathways of a disease. We aim to identify biological processes rather than single genes affected by the chronic fatigue syndrome (CFS). So far, CFS has neither diagnostic clinical signals nor abnormalities that could be diagnosed by laboratory examinations. It is also unclear if the CFS represents one disease or can be subdivided in different categories. We use information from clinical trials, the gene ontology (GO) database as well as gene expression data to identify undirected dependency graphs (UDGs) representing biological processes according to the GO database. The structural comparison of UDGs of sick versus non-sick patients allows us to make predictions about the modification of pathways due to pathogenesis.

 

Source: Emmert-Streib F. The chronic fatigue syndrome: a comparative pathway analysis. J Comput Biol. 2007 Sep;14(7):961-72. https://www.ncbi.nlm.nih.gov/pubmed/17803373

 

Diagnosis and management of chronic fatigue syndrome or myalgic encephalomyelitis (or encephalopathy): summary of NICE guidance

Data from other countries indicate that chronic fatigue syndrome (also known as myalgic encephalomyelitis or myalgic encephalopathy) (CFS/ME) is relatively common (affecting at least 0.2-0.4% of the population), although good epidemiological data for the United Kingdom are lacking. Many different potential aetiologies for CFS/ME have been investigated, including neurological, endocrine, immunological, genetic, psychiatric, and infectious, but the aetiology cannot yet be fully explained. CFS/ME can cause prolonged illness and disability and substantially affect patients and their families. Although most patients have mild or moderate symptoms, some have severe CFS/ME and are housebound or even unable to move from their bed. Uncertainties about diagnosis and management may exacerbate the impact of symptoms, and patients often encounter delays in diagnosis and difficulty accessing information, support, and potentially helpful therapies.1 This article summarises the most recent guidance from the National Institute for Health and Clinical Excellence (NICE) on diagnosing and managing this condition.2

 

Source: Baker R, Shaw EJ. Diagnosis and management of chronic fatigue syndrome or myalgic encephalomyelitis (or encephalopathy): summary of NICE guidance. BMJ. 2007 Sep 1;335(7617):446-8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1962830/ (Full article)

 

Chronic fatigue syndrome or myalgic encephalomyelitis

Comment on: Diagnosis and management of chronic fatigue syndrome or myalgic encephalomyelitis (or encephalopathy): summary of NICE guidance. [BMJ. 2007]

The uncertainty inherent in making a diagnosis of chronic fatigue syndrome (CFS) is reflected by the variety of names (such as myalgic encephalomyelitis; ME) it has been given. The names reflect the hope that such labels can impose some certainty where little exists. Many doctors are reluctant to make a diagnosis of CFS, with half not even believing it exists.1 The consequences of this uncertainty and reluctance have been that patients hear mixed messages and often receive poor, if any, care.2 It is therefore a welcome relief that the National Institute for Health and Clinical Excellence (NICE) has just published clinical guidelines on the diagnosis and management of this disease.3 In this week’s BMJ, Baker and Shaw summarise the guidelines.4

You can read the rest of this comment here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1962896/

 

Source: White P, Murphy M, Moss J, Armstrong G, Spencer P. Chronic fatigue syndrome or myalgic encephalomyelitis. BMJ. 2007 Sep 1;335(7617):411-2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1962896/ (Full article)