Researchers
Gemma Samms and Chris Ponting
Institution
University of Edinburgh
Publication
Samms, G.L., Ponting, C.P. Unequal access to diagnosis of myalgic encephalomyelitis in England. BMC Public Health 25, 1417 (2025). https://doi.org/10.1186/s12889-025-22603-9
Funding
This project is funded by ME Research UK. Funding for access to data was provided by the National Institute for Health and Care Research (NIHR) and Medical Research Council (MRC).
Key findings
- Using hospital data from England, the researchers estimate that 0.25% of men and 0.92% of women in the UK have a diagnosis of post-viral fatigue – the diagnosis with symptoms most closely matching ME/CFS.
- They suggest that if these rates were applied to the 68.3 million people in the UK in 2023, the number of people who would have a diagnosis of post-viral fatigue syndrome would be 403,922.
- Rates of post-viral fatigue syndrome vary by age, sex, GP practice, ethnicity and level of deprivation.
Background
Gemma Samms is a PhD student at the University of Edinburgh, whose research investigating genetic risk factors for ME/CFS using data from the DecodeME project is funded by ME Research UK.
Alongside her supervisor Professor Chris Ponting, who leads DecodeME, Gemma has published a study in the journal “BMC Public Health”. This article considers the number of people with a diagnosis of the medical code most closely matching the symptoms of ME/CFS in England (International Classification of Diseases (ICD)-10: G93.3 for “post viral fatigue syndrome”), and looks at whether rates of this diagnosis vary between different groups of the population.
The important study has been covered widely by news outlets including The Guardian, The Times (paywall), Mirror, University of Edinburgh, and msn.
Methods
The researchers used information recorded in hospital records – hospital episode statistics (HES) data – for 62,782,175 people in England between 1 April 1989 and 7 October 2023.
Using this dataset, the team were able to identify the number of people who had been diagnosed with the medical code for “post viral fatigue syndrome” (ICD-10: G93.3), the diagnostic code which, according to the authors, “best reflects ME/CFS symptoms“. They also looked at differences in rates of G93.3 diagnosis by characteristics such as sex and ethnicity.
It is essential to note that the HES data used by the researchers in this study only reflect information from hospital visits or outpatient appointments (secondary care), it does not capture those diagnoses made only in General Practice (GP) (primary care).
“HES is a curated data product containing details about admissions, outpatient appointments and historical accident and emergency attendances at NHS hospitals in England” – NHS England
Despite this, for the people in the HES dataset, information is provided on which GP practice they are registered with, and the integrated care board (ICB) – NHS organisations responsible for planning health services for their local population – the GP practice is associated with. Importantly, this information allowed the researchers to look for potential inequalities in G93.3 diagnosis rates by GP practice and ICB.
Results
On 7 October 2023, 100,055 people in England – 0.16% of the 62,782,175 individuals in the study – had been diagnosed with the ICD code most closely matching the symptoms of ME/CFS (G93.3).
Women in the study were almost four times more likely to have a diagnosis of G93.3 compared with men. There were 79,445 (0.25% of 31,297,675) females and 20,590 (0.065% of 31,481,510) males with a G93.3 diagnosis – a female to male ratio of approximately 4:1.
Interestingly, the female and male prevalence of a G93.3 diagnosis varied greatly across all the ICBs. For females, it was lowest in Northwest London at 0.086%, and highest in Cornwall at 0.82%; for males, it was lowest in Northeast London at 0.024%, and highest in the Isles of Scilly at 0.21%.
Prevalence of the diagnostic code G93.3 also varied by:
- Age: Prevalence peaked at about age 50 for females, and over a decade later for males. At ages 40–50 and 50–60, the female to male ratio peaked at an “exceptionally high value” of around 6:1.
- Ethnicity: Prevalence in those from white ethnic groups was 4.9-fold higher than those from “other-than-white” ethnic groups. Notably, those with Chinese, Asian/Asian British, or Black/Black British ethnicity were 11%, 11% to 19%, or 10% to 35%, respectively, less likely to have a G93.3 diagnosis.
- Level of deprivation: Prevalence of G93.3 diagnosis was lowest for those living in the three most deprived groups.
- GP practice: 3% of the GP practices included in the study did not have any registered ‘patients’ with the diagnostic code G93.3 – these GP practices are in the most deprived areas of England.
Discussion
In the discussion section of the paper, the authors take the G93.3 prevalence rates for males and females facing the least barriers to diagnosis in England (0.25% for males and 0.92% for females) and extrapolate them to the most recent UK population size of 68.3 million people.
This calculation suggests that if the prevalence rates for England apply to all people in the UK, 83,626 males (0.25% of 33.450 million males in the UK) and 320,296 females (0.92% of 34.815 million females in the UK) would be given a G93.3 diagnosis in their lifetime; i.e. 403,922 people in total. This would equate to a prevalence rate of approximately 0.6%.
Importantly, Samms and Ponting note that the estimate of 403,922 is 62% higher than the previous estimate of 250,000 people with ME/CFS quoted in the 2021 NICE guidelines for the diagnosis and management of the disease.
The study also identified that men, “other-than-white” ethnic groups, and those living in the most deprived areas are less likely to have a diagnosis of “post viral fatigue syndrome” compared with women, white ethnic groups, and those living in more affluent areas, respectively. In the paper, the authors summarise that:
“ME/CFS diagnosis in England is highest among older, white females, and lowest among younger other-than-white males, the variation is 50-fold between these categories”
What are the limitations of the study?
The data are from England rather than the whole of the UK
Although the prevalence rates calculated using data for England were extrapolated by the authors to provide an estimate of the number of people in the UK with the diagnostic code G93.3, prevalence rates vary by location, and the rates observed in England may not reflect those in Scotland, Wales or Northern Ireland.
The medical records are for a diagnosis for G93.3
This refers to “post-viral fatigue syndrome” rather than ME/CFS specifically. It is possible that not all those with a G93.3 diagnosis would meet more stringent ME/CFS diagnostic criteria.
Only those with a G93.3 diagnosis are included in the estimate
Many people with ME/CFS may be undiagnosed. It is likely that there are people yet to be diagnosed with ME/CFS (G93.3) who are not represented in the prevalence estimates calculated in this study. Regrettably, many people with ME/CFS experience a delay in diagnosis or misdiagnosis, and some – especially men with ME/CFS – have reported that they delay seeking medical help for symptoms due to the stigma associated with the disease.
The study period includes diagnoses made under both versions of the NICE guideline for ME/CFS
Unlike the updated 2021 guidelines, the 2007 version did not require either cognitive difficulties or unrefreshing sleep for a diagnosis of ME/CFS to be made. The 2007 guidelines were also less clear about the requirement for the cardinal symptom of ME/CFS – post-exertional malaise.
The data are from hospital and outpatient appointments only
The HES data used in the study do not include diagnoses made at GP practices that were not also recorded in hospital records, meaning the prevalence rate calculated in this study may be an underestimation. In the paper, the authors state that in the UK Biobank only 28% of those with an “ME/CFS code” in their GP records also have the code G93.3 in their hospital records. Despite this, “post viral fatigue syndrome” may be relatively less commonly diagnosed in the primary care setting.
The accuracy of HES data relies on how clearly and correctly information is recorded
Accuracy and completeness of information recorded in medical records can vary between clinicians, over time, and by location.
Prevalence estimates are likely to be an underestimate
Due to the limitations of the hospital data used, the researchers suggest that the prevalence estimates calculated in the study are likely to underestimate the number of people with ME/CFS.
Conclusion
In this paper, the authors calculate updated prevalence rates for ME/CFS of 0.25% for men and 0.92% for women, based on hospital data from England. If these figures are applied to the UK population of 68.3 million in 2023, this suggests that 403,922 people (0.6% of the population) in the UK would have a G93.3 diagnosis in their lifetime.
Samms and Ponting note that while it is possible not all those with a G93.3 diagnosis would meet more stringent diagnostic criteria for ME/CFS, this may not change the estimated prevalence rate. According to the researchers, even if half of those with a G93.3 diagnosis did not meet more stringent diagnostic criteria for ME/CFS, the “reduction could be offset by those diagnosed in primary or private health care“.
Importantly, the results also highlight that there may be inequalities in ME/CFS diagnosis rates in England – the prevalence of the diagnostic code G93.3 clearly varied by age, ethnicity, level of deprivation, and GP practice. Notably, it was those in “underserved groups” – populations that receive less than adequate access to resources, services, or representation – who had the lowest rates of diagnosis.
More research is needed to identify why rates of G93.3 diagnosis appear to be significantly lower in underserved groups, especially as research has suggested some of the ethnic groups with low diagnostic rates observed in the study by Samms and Ponting may actually have a higher risk of ME/CFS.
ME Research UK notes that it is important that, where appropriate, researchers work with people from underserved groups, following relevant patient and public involvement guidelines such as the UK Standards for Public Involvement, to identify research methods that are the most suitable, inclusive and accessible for these populations.
It is also essential that researchers consider how intersectionality – the idea that where people belong to more than one underserved group, they may face multiple disadvantages – may impact on ME/CFS diagnostic rates and barriers to diagnosis.
