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Open Access Highly Accessed Research article

Prevalence of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in three regions of England: a repeated cross-sectional study in primary care

Luis C Nacul12*, Eliana M Lacerda1, Derek Pheby3, Peter Campion4, Mariam Molokhia5, Shagufta Fayyaz1, Jose CDC Leite6, Fiona Poland6, Amanda Howe6 and Maria L Drachler6

Author affiliations

1 Department of Nutrition and Public Health Interventions Research, London School of Hygiene and Tropical Medicine (LSHTM), Keppel Street, London, WC1E 7HT, UK

2 Foundation for Genomics and Population Health (PHGF), Cambridge, CB1 8RN, UK

3 National ME Observatory Project Coordinator, and Bucks New University, Queen Alexandra Road, High Wycombe, Buckinghamshire, HP11 2JZ, UK

4 Hull-York Medical School, University of Hull, Hull, HU6 7RX, UK

5 Department of Primary Care and Public Health Sciences, Division of Health and Social Care Research. Kings College, London, SE1 3QD, UK

6 University of East Anglia, Norwich, NR47TJ, UK

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Citation and License

BMC Medicine 2011, 9:91  doi:10.1186/1741-7015-9-91

Published: 28 July 2011

Abstract

Background

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) or chronic fatigue syndrome (CFS) has been used to name a range of chronic conditions characterized by extreme fatigue and other disabling symptoms. Attempts to estimate the burden of disease have been limited by selection bias, and by lack of diagnostic biomarkers and of agreed reproducible case definitions. We estimated the prevalence and incidence of ME/CFS in three regions in England, and discussed the implications of frequency statistics and the use of different case definitions for health and social care planning and for research.

Methods

We compared the clinical presentation, prevalence and incidence of ME/CFS based on a sample of 143,000 individuals aged 18 to 64 years, covered by primary care services in three regions of England. Case ascertainment involved: 1) electronic search for chronic fatigue cases; 2) direct questioning of general practitioners (GPs) on cases not previously identified by the search; and 3) clinical review of identified cases according to CDC-1994, Canadian and Epidemiological Case (ECD) Definitions. This enabled the identification of cases with high validity.

Results

The estimated minimum prevalence rate of ME/CFS was 0.2% for cases meeting any of the study case definitions, 0.19% for the CDC-1994 definition, 0.11% for the Canadian definition and 0.03% for the ECD. The overall estimated minimal yearly incidence was 0.015%. The highest rates were found in London and the lowest in East Yorkshire. All but one of the cases conforming to the Canadian criteria also met the CDC-1994 criteria, however presented higher prevalence and severity of symptoms.

Conclusions

ME/CFS is not uncommon in England and represents a significant burden to patients and society. The number of people with chronic fatigue who do not meet specific criteria for ME/CFS is higher still. Both groups have high levels of need for service provision, including health and social care. We suggest combining the use of both the CDC-1994 and Canadian criteria for ascertainment of ME/CFS cases, alongside careful clinical phenotyping of study participants. This combination if used systematically will enable international comparisons, minimization of bias, and the identification and investigation of distinct sub-groups of patients with possibly distinct aetiologies and pathophysiologies, standing a better chance of translation into effective specific treatments.