The Role of Delayed Diagnosis in the Development of Severe ME/CFS

Approximately 25% of people with ME/CFS can be categorised as severely affected i.e. they are wheelchair-bound, house-bound, or bed-bound and presenting with a multitude of complex symptoms that dramatically affect quality of life, to such an extent that the level of impairment in severe ME/CFS is more extreme than in end-stage renal disease and heart disease.

Of particular concern to the ME Alliance is the role of diagnostic delay in the development of severe ME.

Research epidemiologist Dr Derek Pheby has carried out a study of risk factors which might be involved in the development of severe ME/CFS. Data obtained from questionnaires received from 124 severely affected people with ME/CFS was compared to a control group of 619 mild or moderately affected.

A key finding from analysis of the results is that severity is linked to the length of time before a diagnosis was made:  Those who were ill for more than a year before receiving a diagnosis from a doctor were more likely to be severely ill than those who waited less than a year. Only 27% of severe cases were diagnosed within a year compared to 54% of those who were mild or moderately affected.


ME Alliance, ME/CFS Diagnosis: “Delay Harms Health Early diagnosis: why is it so important? A report from the M.E. Alliance”, Dr Charles Shepherd.

Derek Pheby and Lisa Saffron, “Risk factors for severe ME/CFS“, Biology and Medicine, 2009, 1 (4): 50-74.


Why early diagnosis is important

Doctors and diagnosis – or not

How should a diagnosis be made?

Diagnosis in acute onset ME/CFS

Diagnosis in gradual onset ME/CFS

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