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The prevalence of chronic fatigue syndrome/ myalgic encephalomyelitis: a meta-analysis


Senior Member
Don't think this has been posted yet. From Marshall et al in Australia.


26 March 2013.

Samantha Johnston,1 Ekua W Brenu,1 Donald Staines,1,2 Sonya Marshall-Gradisnik1
1Griffith Health Institute, School of Medical Sciences, National Centre for Neuroimmunology and Emerging Diseases, Griffith University, Parklands, QLD, Australia; 2Gold Coast Public Health Unit, Queensland Health, Robina, QLD, Australia

Purpose: To perform a meta-analysis to examine variability among prevalence estimates for CFS/ME, according to the method of assessment used.
Methods: Databases were systematically searched for studies on CFS/ME prevalence in adults that applied the 1994 Centers for Disease Control (CDC) case definition.1 Estimates were categorized into two methods of assessment: self-reporting of symptoms versus clinical assessment of symptoms. Meta-analysis was performed to pool prevalences by assessment using random effects modeling. This was stratified by sample setting (community or primary care) and heterogeneity was examined using the I2 statistic.
Results: Of 216 records found, 14 studies were considered suitable for inclusion. The pooled prevalence for self-reporting assessment was 3.28% (95% CI: 2.24–4.33) and 0.76% (95% CI: 0.23–1.29) for clinical assessment. High variability was observed among self-reported estimates, while clinically assessed estimates showed greater consistency.
Conclusion: The observed heterogeneity in CFS/ME prevalence may be due to differences in method of assessment. Stakeholders should be cautious of prevalence determined by the self-reporting of symptoms alone. The 1994 CDC case definition appeared to be the most reliable clinical assessment tool available at the time of these studies. Improving clinical case definitions and their adoption internationally will enable better comparisons of findings and inform health systems about the true burden of CFS/ME.


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The overall, pooled prevalence for self-reported CFS/ME was 3.48% (95% CI: 2.36–4.60) and high heterogeneity was observed (I 2 = 58%).

All samples were community-based.

The overall, pooled prevalence of CFS/ME detected with clinical assessment was low at 0.76% (95% CI: 0.23–1.29) and no heterogeneity was detected (I 2 = 0%).

It would be good to know the details of 'heterogeneity' and 'clinical assessment' but it looks like one would need to read the other studies to get the latter.

ETA: then again, maybe they mean this:

It is not uncommon for studies to apply further tools to help verify suspicions of CFS/ME, such as empirical criteria, 32 validated health surveys, 33 fatigue scores, 34 and depression scales. 35 Some studies have then proceeded with clinical diagnosis of CFS/ME.


Senior Member
Donald Staines

I think this fellow is worth keeping an eye on (in a good way). :)