Chronic fatigue syndrome is characterized by disabling fatigue that is not associated with work load or other medical diagnosis. Patients also present with concurrent symptoms such as sore throat, sleep disturbances, dizziness, increased sensitivity (e.g. light and sound) and muscle and joint pain, and headaches.
The Norwegian Knowledge Centre for Health Services was commissioned by the Norwegian Directorate of Health to review the current evidence related to effect of treatment, rehabilitation and care for people with chronic fatigue syndrome.
- Work and school participation: cognitive behavioural therapy may be associated with some improvements in work and school participation.
- Fatigue: cognitive behavioural therapy or exercise therapy is likely to reduce fatigue compared to usual care or relaxation/ straining. With regard to pharmacological treatment, the quality of evidence is in general very limited.
- Quality of life: cognitive behavioural therapy is likely to improve the quality of life compared with standard care or other psychotherapies. The effect of exercise therapy is not statistically significant compared to standard treatment. The effect of exercise therapy is not statistically significant. But the effect estimate is uncertain. In the best case, exercise therapy is associated with large positive effects, worst case exercise therapy is associated with a small or no difference in quality of life.
- The quality of evidence is too poor or lacking to allow conclusion regarding the effect of dietary supplements and alternative treatment.
- There is a need to review clinical effectiveness studies on care as well as rehabilitation.
Based on a prevalence of 0.2 to 0.4 %, there are approximately 10000 to 200000 residents with chronic fatigue syndrome in Norway. Chronic fatigue syndrome is diagnosed on the basis of different sets of diagnostic criteria, which have in common that other diagnosis be associated with chronic fatigue should be excluded. The main symptom is persistent fatigue which reduces activity level and participation. Concurrent symptoms such as impaired memory, loss of concentration, sore throat, muscle and joint pains, headaches and sleep disturbances often appear. These symptoms can result in severe functional disability, and some patients are bedridden.
The Norwegian Knowledge Centre for Health Services was commissioned by the Norwegian Directorate of Health to prepare an updated an overview of evidence regarding treatment, rehabilitation, and care of those who have chronic fatigue syndrome. Moreover, we publish three separate memoranda regarding: diagnostic criteria, ongoing published trials and research published in scientific journals the last ten years with Professor Kenny De Meirleir on the list of authors.
Searches for systematic reviews on the effect of treatment for patients with chronic fatigue syndrome were completed in February 2011. We searched the following databases: Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessments Database, MEDLINE, PsycINFO, Amed, EMBASE , CINAHL, SveMed and BMJ Clinical Evidence. If we identified several systematic reviews on the same topic, we included the most recent systematic review with the highest quality. Assessment of methodological quality, data extraction and assessment of the overall quality of the evidence was done independently by two authors. We evaluated treatment effect with respect on three pre-defined outcomes: employment status, fatigue, and health-related quality of life.
We have synthesised results from five systematic reviews summarising 35 relevant primary studies with a total of 2474 participants:
Back to work or school
One systematic review included two small primary studies reporting "back to school or work”. Both primary studies measured the effect of cognitive behavioural therapy (CBT) focusing on increased activity versus standard treatment during a 12-month follow-up period. One study showed increased employment status in the CBT group (RR=3.2, 95 % CI 1.5 to 6.8). Results reported from the other study show no difference in the recorded days of absence from work between the CBT and the control group (MD = 4.4 days, 95% CI -50.1 to 58.8). The quality of the evidence was assessed as respectively low and very low.
One systematic review included nine primary studies and reported that cognitive behavioural therapy (CBT) in short and long term (12-month follow-up) as compared to standard treatment (six primary studies) or other forms of psychotherapy (four primary studies) was likely to contribute to less fatigue. The quality of this evidence is moderate. Another systematic review included data from seven primary studies showing that graded exercise therapy is likely to decrease level of fatigue compared to relaxation and stretching (moderate quality evidence). The review cites one primary study reporting long-term effect (52 weeks) of exercise therapy on fatigue, showing no statistically significant differences between the exercise and control groups (low quality evidence). A third systematic review reports results from four primary studies of various pharmacological treatments. None of the pharmacological treatments are more effective than placebo measured on the level of fatigue, and adverse effects are reported.
Health-related quality of life
One systematic review cites one primary study measuring compares cognitive behaviour therapy (CBT) with standard treatment or other forms of psychotherapy and shows a slight improvement in quality of life (EuroQol). The effect lasted six months after treatment (MD 8.0 points, 95% CI 0.7 to 15.3). The quality of the evidence is low. One systematic review looking at exercise therapy included five primary studies, and concluded that exercise therapy does not lead to statistically significant changes in quality og life (SF-36 physical function)at short-term (12-15 weeks) (MD 7.1 points 95% CI -0.5 to 14.6) or at long-term (52 weeks) (MD 9.0 points, 95% CI -1.0 to 19.0). However, the confidence intervals are wide ranging from a large positive effect to no effect. Thus, the effectiveness of exercise therapy is uncertain, and we can’t out-rule a positive effect of exercise therapy on health-related quality of life.
Need for more evidence
In the case of non-pharmacological supplements and alternative therapy, the quality of the evidence is too poor to allow firm conclusions. We did not find systematic reviews examining the effect of care or rehabilitation, about the most seriously ill people with chronic fatigue syndrome nor children and adolescents.
With regard to the effects of cognitive behavioural therapy and graded exercise therapy, our results correspond well to what was presented in the report: ”Diagnostisering og behandling av kronisk utmattelsessyndrom/myalgisk encefalopati (CFS/ME)” (translated to English: “Diagnosis and treatment of chronic fatigue syndrome/myalgic encephalopathy (CFS/ME)) from 2006. Both strategies may contribute to reduced fatigue and may perhaps increase quality of life, but less is known about how cognitive behaviour therapy and exercise therapy effect on employment status. For drug therapy, immunotherapy, nutritional supplements and alternative therapies the 2006 report conclude that evidence is lacking, and it does not seem to have accumulated evidence in the mean time that contribute to changes in these conclusions. It should be emphasized that the current report is based on other systematic reviews, and as a consequence, we have not included primary studies published after the search dates reported in the reviews we are citing.
The primary studies we refer to in this report have used different sets of diagnostic criteria, including the Centre for Disease Control and Prevention (CDC) 1994 criteria, Oxford 1991 criteria, and Australian 1990 criteria. Theoretically, diagnostic criteria can help us define selected and more homogeneous groups of patients, and there is a possibility that treatment effect will vary between studies using different sets of diagnostic criteria. Currently we see no signs that this is the case, but as more studies become available, it will be possible to conduct more comprehensive analysis concerning the relationship between the use of different sets of diagnostic criteria and observed treatment effect. None of the studies includes severely ill patients or children and young people.
Cognitive behavioural therapy and graded exercise therapy is likely to be effective for people with chronic fatigue syndrome. For other treatment strategies the quality of evidence is very low or even non-existing implying that more research is needed before we can make firm conclusions about treatment effect.