Systematic review of the current literature related to disability and chronic fatigue syndrome

Abstract:

Objective: The objective of this evidence report was to perform a systematic review of the published literature to provide the Social Security Administration (SSA) with the best available evidence and most current medical knowledge regarding disability in persons with Chronic Fatigue Syndrome (CFS).

Search Strategy: English language and adult population published literature from 1988 to November 2001 was searched using MEDLINE, Current Contents, Cochrane Library, and PsychINFO databases and supplemented by a manual review of bibliographies of all accepted papers.

Selection Criteria: Interventional or observational studies of at least two adult patients reporting CFS according to either the CDC 1988, CDC 1994, Oxford 1991, or Australia 1990 criteria were accepted. Studies were required to report disability (evidence of a medically determinable physical or mental impairment) and data regarding employment or work.

Data Collection and Analysis: Data on patients, interventions, and outcomes were extracted from accepted studies. Studies were scored for quality and level of evidence. Data were summarized for study, patient, and treatment level characteristics as well as outcomes of interest. A panel of diverse technical experts and peer reviewers provided review and commentary on the draft report.

Main Results: Of 3,840 citations identified, 53 studies describing 4,558 patients with CFS met all eligibility criteria. Twenty-two of these studies described comparator groups of healthy controls totaling 775 patients. The majority of CFS patients represented in the 37 studies reporting employment status were unemployed. The evidence suggests that some individuals with CFS have cognitive or affective impairments on neuropsychological tests, but results are not consistent. Depression of greater severity is associated with unemployment, but no other impairment appeared to be consistently associated with disability or work outcomes. No specific interventions have been proven to be effective in restoring the ability to work. No specific patient characteristics have been identified as best predictors of positive employment outcomes in CFS patients. The patient’s level of functioning at the time of diagnosis should be compared to functioning prior to the onset of illness especially as it relates to work, school, social and home activities.

The major limitations of this review are related to the weaknesses inherent in the current medical and scientific published literature regarding CFS. Study designs were not sufficiently homogeneous to allow quantitative synthesis of individual study results, and external validity was low. While some studies reported test and scale results, this was highly variable with relatively sparse and inconsistent reporting of both baseline and outcome data. No studies specifically measured the impact of baseline impairment data or treatment interventions on work function or employment outcomes.

Conclusions: While relationships between various impairment measures and work/disability status might be explored in some cases, the best available evidence from the literature did not allow for determination of causality. The limitations inherent in the current literature review are noted and the research community is urged to conduct methodologically rigorous, longitudinal, interventional studies to determine what baseline characteristics are associated with inability to work, and what interventions are effective in restoring the ability to work in the CFS population.

 

Source: Ross SD, Levine C, Ganz N, Frame D, Estok R, Stone L, Ludensky V. Systematic review of the current literature related to disability and chronic fatigue syndrome. Evid Rep Technol Assess (Summ). 2002 Dec;(66):1-3. http://www.ncbi.nlm.nih.gov/books/NBK36735/ (Full article)

 

Effect of natural and synthetic antioxidants in a mouse model of chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is an illness characterized by persistent and relapsing fatigue, often accompanied by numerous symptoms involving various body systems. The etiology of CFS remains unclear; however, a number of studies have shown that oxidative stress may be involved in its pathogenesis. In the present study, a mouse model of CFS was used in which mice were forced to swim for one 6-minute session on each day for 15 days and the immobility period was recorded.

There was a significant increase in immobility period in saline-treated mice on successive days. Intraperitoneal treatment with the potent antioxidants carvedilol (5 mg/kg) and melatonin (5 mg/kg) produced a significant reduction in immobility period. Similar results were observed with herbal preparations administered orally: Withania somnifera (100 mg/kg), quercetin (50 mg/kg), and St. John’s wort (Hypericum perforatum L., 10 mg/kg). Biochemical analysis revealed that chronic swimming significantly induced lipid peroxidation and decreased glutathione (GSH) levels in the brains of mice. The rats also showed decreased levels of antioxidant defense enzymes, superoxide dismutase (SOD), and catalase. Co-administration of antioxidants carvedilol, melatonin, W. somnifera, quercetin or St. John’s wort significantly reduced lipid peroxidation and restored the GSH levels decreased by chronic swimming in mice. Further, the treatment increased levels of SOD in the forebrain and of catalase.

The findings strongly suggest that oxidative stress plays a significant role in the pathophysiology of CFS and that antioxidants could be useful in the treatment of CFS.

 

Source: Singh A, Naidu PS, Gupta S, Kulkarni SK. Effect of natural and synthetic antioxidants in a mouse model of chronic fatigue syndrome. J Med Food. 2002 Winter;5(4):211-20. http://www.ncbi.nlm.nih.gov/pubmed/12639396

 

Variability in diagnostic criteria for chronic fatigue syndrome may result in substantial differences in patterns of symptoms and disability

Abstract:

Chronic fatigue syndrome (CFS) is an illness that involves severe, prolonged exhaustion as well as neurologic, immunologic, and endocrine system pathology. Because the pathogenesis of CFS has yet to be determined, case definitions have relied on clinical observation in classifying signs and symptoms for diagnosis.

The current investigation examined differences between CFS as defined by Fukuda and colleagues and a set of criteria that has been stipulated for myalgic encephalomyelitis (ME). Dependent measures included psychiatric comorbidity, symptom frequency, symptom severity, and functional impairment. The ME and Fukuda et al. (1994) CFS criteria were compared with a group having chronic fatigue due to psychiatric reasons.

Significant differences occurred primarily with neurologic, neuropsychiatric, fatigue/weakness, and rheumatological symptoms. These findings suggest that it might be inappropriate to synthesize results from studies of this illness that use different definitions to select study populations.

 

Source: Jason LA, Helgerson J, Torres-Harding SR, Carrico AW, Taylor RR. Variability in diagnostic criteria for chronic fatigue syndrome may result in substantial differences in patterns of symptoms and disability. Eval Health Prof. 2003 Mar;26(1):3-22. http://www.ncbi.nlm.nih.gov/pubmed/12629919

 

Does graded activity increase activity? A case study of chronic fatigue syndrome

Abstract:

The reliance on self-report outcome measures in clinical trials of graded activity-oriented cognitive-behavior therapy in chronic fatigue syndrome (CFS) makes it difficult to draw definitive conclusions about actual behavioral change.

The participant in this case study was a 52-year-old married male with CFS who was working full-time. Outcome measures included a step counter to objectively measure physical activity as well as a daily diary measure of exercise activity and in vivo ratings of perceived energy, fatigue, and affect. The following psychometric instruments were also used: the CFS Symptom Inventory, the SF-36, the Beck Depression Inventory, and the Beck Anxiety Inventory. The 26-session graded activity intervention involved gradual increases in physical activity.

From baseline to treatment termination, the patient’s self-reported increase in walk time from 0 to 155 min a week contrasted with a surprising 10.6% decrease in mean weekly step counts. The final follow-up assessment revealed a “much improved” global rating, substantial increases in patient-recorded walk time and weight lifting intensity, yet a relatively modest increment in weekly step counts. It appeared that improvement was associated with mood-enhancing, stress-reducing activities that were substituted for stress-exacerbating activities.

Copyright 2003 Elsevier Science Ltd.

 

Source: Friedberg F. Does graded activity increase activity? A case study of chronic fatigue syndrome.  J Behav Ther Exp Psychiatry. 2002 Sep-Dec;33(3-4):203-15. http://www.ncbi.nlm.nih.gov/pubmed/12628637

 

Chronic fatigue syndrome: symptom subtypes in a community based sample

Abstract:

Most studies of Chronic Fatigue Syndrome (CFS) have been based on patients recruited from primary or tertiary care settings. Patients from such settings might not be typical of patients in the general population. The present investigation involved examining individuals with CFS from a community-based study. A random sample of 18,675 respondents in Chicago were first interviewed by telephone. A group of individuals with chronic fatigue accompanied by at least four Fukuda et al. (1994) symptoms associated with CFS were given medical and psychiatric examinations. From this sample, a physician review group diagnosed individuals with CFS. Those diagnosed with CFS were subclassified based on frequency of symptoms. Important differences emerged on measures of sociodemographics and disability. The implications of these findings and others are discussed.

 

Source: Jason LA, Taylor RR, Kennedy CL, Jordan KM, Song S, Johnson D, Torres-Harding S. Chronic fatigue syndrome: symptom subtypes in a community based sample. Women Health. 2003;37(1):1-13. http://www.ncbi.nlm.nih.gov/pubmed/12627607

 

RNase L levels in peripheral blood mononuclear cells: 37-kilodalton/83-kilodalton isoform ratio is a potential test for chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a disorder characterized by debilitating fatigue associated with immunological abnormalities. The etiology remains unclear. A low-molecular-mass (37 kDa) isoform of RNase L has been described in peripheral blood mononuclear cell (PBMC) extracts, and the ratio of two isoforms of RNase L (37 kDa/83 kDa) has been proposed as a potential biochemical marker of CFS. In a prospective case-control study, we tested whether the RNase L 37-kDa/83-kDa ratio could discriminate a SFC population.

We compared the ratio of RNase L isoforms in PBMCs from 11 patients with CFS (6 women and 5 men; mean age +/- standard deviation, 43.2 +/- 13.8 years) and PBMCs from 14 healthy well-matched volunteers (10 women and 4 men; age, 39.1 +/- 11.6 years). A ratio of RNase L of 0.4 used as a threshold allowed diagnosis of CFS with high sensitivity (91%; 95% confidence interval [CI], 57 to 99%) and specificity (71%; 95% CI, 41 to 90%). The positive and negative prognostic values were 71% (95% CI, 41 to 90%) and 91% (95% CI, 57 to 99%), respectively.

In the absence of acute infection or chronic inflammation, a high RNase L ratio could distinguish CFS patients from healthy volunteers. Additional large studies and follow-up studies are required to confirm the stability of this high ratio of RNase L isoforms in a CFS group.

Comment in: 37-Kilodalton/83-kilodalton RNase L isoform ratio in peripheral blood mononuclear cells: analytical performance and relevance for chronic fatigue syndrome. [Clin Diagn Lab Immunol. 2005]

 

Source: Tiev KP, Demettre E, Ercolano P, Bastide L, Lebleu B, Cabane J. RNase L levels in peripheral blood mononuclear cells: 37-kilodalton/83-kilodalton isoform ratio is a potential test for chronic fatigue syndrome. Clin Diagn Lab Immunol. 2003 Mar;10(2):315-6. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC150526/ (Full article)

 

Psychiatric adjustment in chronic fatigue syndrome of childhood and in juvenile idiopathic arthritis

Abstract:

BACKGROUND: High rates of psychopathology and of personality problems have been reported in children and adolescents with chronic fatigue syndrome (CFS). It is not clear whether this is consequent on the experience of chronic physical ill health. We compare psychiatric adjustment in children with CFS and in children suffering from another chronic physical disorder (juvenile idiopathic arthritis or JIA).

METHOD: Our sample consisted of 28 children with CFS and 30 with JIA attending tertiary paediatric centres (age range, 11 to 18 years, mean 15, S.D. 2.3). In order to assess psychiatric status and functioning, we used the K-SADS psychiatric interviews, CGAS and Harter Self-Esteem Questionnaire with child subjects; behavioural questionnaires (CBCL) and child personality assessment interviews (PAS) with parent informants.

RESULTS: Psychiatric disorders in the year prior to interview had been present significantly more commonly in the CFS group (72% v. 34% in JIA) and were more impairing to them (CGAS scores of 45 v. 77). Most common diagnoses in both groups were depressive and anxiety disorders. Personality problems were also significantly more frequent in CFS subjects (48% disorder and 26% difficulty v. 11% and 11% in JIA). There were few differences between the two groups in self-esteem.

CONCLUSIONS: Psychopathology and personality problems are common in children and adolescents with severe forms of CFS and cannot be explained strictly through the experience of chronic physical illness.

Comment in: Costs, correlates and consequences of fatigue in children and adults. [Psychol Med. 2003]

 

Source: Rangel L, Garralda ME, Hall A, Woodham S. Psychiatric adjustment in chronic fatigue syndrome of childhood and in juvenile idiopathic arthritis. Psychol Med. 2003 Feb;33(2):289-97. http://www.ncbi.nlm.nih.gov/pubmed/12622307

 

The economic cost of chronic fatigue and chronic fatigue syndrome in UK primary care

Abstract:

BACKGROUND: Chronic fatigue and chronic fatigue syndrome are most often encountered in primary care settings. Given the disabling nature of chronic fatigue it may have a substantial impact on service use and costs as well as on employment. This study estimates this impact.

METHOD: Patients presenting to general practitioners with unexplained chronic fatigue were recruited to the study. Service use over a 3 month period was measured and lost employment recorded. These data were used to estimate economic costs. Patients with chronic fatigue syndrome were compared to patients with only chronic fatigue using a multiple regression model with sample differences controlled.

RESULTS: The mean total cost of services and lost employment across the sample was Pound Sterling1906 for the 3-month period with formal services accounting for 9.3% of this figure. Service use was higher for patients with chronic fatigue syndrome compared to those with chronic fatigue alone. Total 3-month costs were on average higher for chronic fatigue syndrome (Pound Sterling3515 v. Pound Sterling1176) but when sample differences were taken account of the mean difference was reduced to Pound Sterling1406 (P = 0.086). Over 90% of the cost was accounted for by care provided by friends and family members and by lost employment. Patients with dependants had significantly higher costs than those with none and costs were also significantly higher for greater levels of functional impairment.

CONCLUSION: Chronic fatigue imposes substantial economic costs on society, mainly in the form of informal care and lost employment. Treatments need to be developed which recognize these impacts.

Comment in: Costs, correlates and consequences of fatigue in children and adults. [Psychol Med. 2003]

 

Source: McCrone P, Darbishire L, Ridsdale L, Seed P. The economic cost of chronic fatigue and chronic fatigue syndrome in UK primary care. Psychol Med. 2003 Feb;33(2):253-61. http://www.ncbi.nlm.nih.gov/pubmed/12622304

 

Assessment of cortisol response with low-dose and high-dose ACTH in patients with chronic fatigue syndrome and healthy comparison subjects

Abstract:

A reduced secretion of cortisol has been proposed as a possible explanation of the symptoms in chronic fatigue syndrome. However, the evidence of hypocortisolism in chronic fatigue syndrome is conflicting.

In order to simultaneously assess possible alterations in adrenocortical sensitivity and secretory adrenal reserve, the authors administered both low-dose and high-dose ACTH to a group of 18 chronic fatigue syndrome patients and 18 age- and gender-matched healthy comparison subjects.

No response differences for salivary and plasma cortisol were detectable after administration of either low-dose or high-dose ACTH, indicating that primary adrenal insufficiency is unlikely to play a significant role in the etiology of chronic fatigue syndrome.

 

Source: Gaab J, Hüster D, Peisen R, Engert V, Heitz V, Schad T, Schürmeyer T, Ehlert U. Assessment of cortisol response with low-dose and high-dose ACTH in patients with chronic fatigue syndrome and healthy comparison subjects. Psychosomatics. 2003 Mar-Apr;44(2):113-9. http://www.ncbi.nlm.nih.gov/pubmed/12618533

 

AIDS and CFS/ME: a tale of two syndromes

Abstract:

Both HIV/AIDS and chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) presented major challenges for medicine, science and society. This article explores what could have impeded investigation of–and specifically pharmaceutical engagement with–CFS/ME, in contrast to the impressive achievements seen in HIV/AIDS. It explores the obstruction of mind-body dualism in a historical context, and examines some of the possible obstacles to pharmaceutical enquiry. Nothing of real substance is identified that would justify the lack of investment and interest in solutions for patients with CFS/ME.

Comment in: AIDS and CFS/ME. [Clin Med (Lond). 2003]

 

Source: Pinching AJ. AIDS and CFS/ME: a tale of two syndromes. Clin Med (Lond). 2003 Jan-Feb;3(1):78-82. http://www.ncbi.nlm.nih.gov/pubmed/12617422