Case definitions integrating empiric and consensus perspectives

Abstract

Background: There has been considerable controversy regarding how to name and define the illnesses known as myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). The Institute of Medicine (IOM) report has proposed new clinical criteria and a new name for this illness, but aspects of these recommendations have been scrutinized by patients and scientists. Purpose: It is possible that both empiric and consensus approaches could be used to help settle some of these diagnostic challenges. Using patient samples collected in the USA, Great Britain, and Norway (N = 556), the current study attempted to categorize patients using more general as well as more restricted case definitions. Results: Overall, the outcomes suggest that there might be four groupings of patients, with the broadest category involving those with chronic fatigue (N = 62), defined by six or more months of fatigue which cannot be explained by medical or psychiatric conditions. A second category involves those patients who have chronic fatigue that can be explained by a medical or psychiatric condition (N = 47). A third category involves more specific criteria that have been posited both by the IOM report, Canadian Clinical Case criteria, ME-ICC criteria and a more empiric approach. These efforts have specified domains of substantial reductions of activity, post-exertional malaise, neurocognitive impairment, and sleep dysfunction (N = 346). Patients with these characteristics were more functionally impaired than those meeting just chronic fatigue criteria, p < .05. Finally, those meeting even more restrictive ME criteria proposed by Ramsay, identified a smaller and even more impaired group, p < .05. Conclusion: It is important that scientists world-wide develop consensus on how to identify and classify patients using clinical and research criteria, and ultimately develop subtypes within such categories.

Keywords:

• myalgic encephalomyelitis
• chronic fatigue syndrome
• case definition

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors appreciate the funding provided by NIAID [grant numbers AI 49720 & AI 055735].

Notes on contributors

Leonard A. Jason

Leonard A. Jason is the Director of the Center for Community Research and Professor of Psychology at DePaul University.

Stephanie McManimen

Stephanie McManimen is a research assistant at the Center for Community Research.

Madison Sunnquist

Madison Sunnquist is currently a graduate student in the Clinical-Community Psychology doctoral program at DePaul University.

Abigail Brown

Abigail Brown is currently a graduate student in the Clinical-Community Psychology doctoral program at DePaul University.

Jacob Furst

Jacob Furst is a professor in the College of Computing and Digital Media at DePaul University.

Julia L. Newton

Julia L. Newton is the Dean of Clinical Medicine and Clinical Professor of Ageing and Medicine at Newcastle University in the UK.

Elin Bolle Strand

Elin Bolle Strand is the Managing Director at Oslo University Hospital.