Evaluating case diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): toward an empirical case definition

Abstract

Purpose

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is an illness characterized by a variety of symptoms including post-exertional malaise, unrefreshing sleep, and cognitive impairment. A variety of case definitions (e.g., the Canadian Consensus Criteria (CCC), the Myalgic Encephalomyelitis International Consensus Criteria (ME-ICC), and the Institute of Medicine (IOM) criteria) have been used to diagnose patients. However, these case definitions are consensus-based rather than empirical.

Materials and methods

The aim of the current study was to evaluate the validity of the aforementioned case definitions by factor analyzing a large, international sample (N = 2308) of ME/CFS symptom data. We performed primary and secondary exploratory factor analyses on the DePaul Symptom Questionnaire's 54-item symptom inventory. These results were compared to the CCC, the ME-ICC, and the IOM criteria.

Results

We identified seven symptom domains, including post-exertional malaise, cognitive dysfunction, and sleep dysfunction. Contrary to many existing case criteria, our analyses did not identify pain as an independent factor.

Conclusions

Although our results implicate a factor solution that best supports the CCC, revisions to the criteria are recommended.

Implications for rehabilitation

• ME/CFS is a chronic illness with no consensus regarding case diagnostic criteria, which creates difficulty for patients seeking assistance and disability benefits.

• The current study compared three commonly used case definitions for ME/CFS by factor analyzing symptomological data from an international sample of patients.

• Our results suggest three primary and four secondary symptom domains which differed from all three case definitions.

• These findings could help reduce barriers to care for those disabled with ME/CFS by guiding the development of an empirically-based case definition.

Keywords:

• Myalgic encephalomyelitis/chronic fatigue syndrome
• chronic illness
• case definitions
• diagnostic criteria
• factor analysis

Acknowledgements

The authors acknowledge the contributions of Julia L. Newton, Elin Bolle Strand, Jesus Castro-Marrero, and Ruud Vermeulen, as well as the Solve ME/CFS Initiative, which approved the use of de-identified Solve ME/CFS BioBank registry data.

Informed consent: Informed consent was obtained from all participants involved in the study.

Disclosure statement

The authors disclose no conflicts of interest.

Data availability statement

The data presented in this study are available from the corresponding author upon reasonable request.

Additional information

Funding

Research reported in this publication was supported by the National Institute Of Neurological Disorders And Stroke of the National Institutes of Health under Award Number R01NS111105. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.