Beyond myalgic encephalomyelitis/chronic fatigue syndrome: an IOM report on redefining an illness.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a multisystem and often long-lasting disorder, with manifestations that can cause substantial morbidity and can severely impair patients’ health and wellbeing. It is estimated that between 836 000 and 2.5 million individuals are affected in the United States.1,2 Patients with ME/CFS are typically unable to perform their normal activities, and as many as one-fourth are homebound or bedridden, sometimes for extended periods.3 As a result, the personal and social effects and ramifications of this disease are enormous. However, ME/CFS is poorly accepted and poorly understood, and the characteristics necessary to make the diagnosis are contested. Patients’ concerns are often met with dismay and skepticism, if not outright dismissal. Clinicians, in turn, are confronted by competing definitions, which were usually developed for research and are quite complex and difficult to implement in a busy clinical practice. Patients who are fortunate enough and persistent enough to receive a correct diagnosis frequently report long delays before their disorder was identified. It is almost certainly the case that the majority of affected patients are never diagnosed. This is unfortunate because effective symptom management is often available, whereas the wrong interventions can make symptoms worse. Making the diagnosis is essential for providing appropriate care. To that end, the Department of Health and Human Services (HHS), together with the National Institutes of Health, US Social Security Administration, US Food and Drug Administration, Centers for Disease Control and Prevention, and Agency for Healthcare Research and Quality, tasked the Institute of Medicine (IOM) to develop “evidence-based clinical diagnostic criteria for ME/CFS for use by clinicians, using a consensusbuilding methodology,” with input from patients and clinicians; to “recommend whether new terminology for ME/CFS should be adopted”; and to create plans for disseminating these conclusions to clinicians. To meet its charge, the IOM committee heard testimony from patients, clinicians, and researchers, carefully reviewed almost one thousand public comments, and conducted a comprehensive literature review. Currently available evidence permitted the committee, in its newly released report,4 to identify symptoms and findings that collectively identify the disorder for which a new name was proposed, as discussed below. These criteria are set forth in the accompanying Box. To assist with diagnosis, the committee developed an algorithm incorporating these criteria as well as an extensive list of findings on history, physical examination, and, when needed to clarify symptoms, tests that support the diagnosis. Further details, including recommended checklists, are contained in the committee’s report.4 The committee called on HHS to develop focused, evidence-based tools that will help clinicians make this diagnosis efficiently. Patients with ME/CFS, like many other patients, often have comorbid conditions that clinicians also must be prepared to identify and treat. The committee concluded that a new name— systemic exertion intolerance disease—was warranted to capture the essence of this disorder until causation and pathophysiology are better delineated by research. Although patients differ in their triggers and manifestations, the salient feature of this disorder is that any kind of exertion—physical, cognitive, emotional— can adversely affect these patients in many aspects of their biological function and in their lives, frequently severely and often for a prolonged period. “Myalgic encephalomyelitis,” for which many people who provided input to the IOM study through testimony and public comments advocated, simply does not describe this disorder. “Chronic fatigue syndrome” fails to depict the complexity of this disease and is also unacceptable to many patients and their advocates, who reported that this term leads clinicians and others to belittle or even dismiss their VIEWPOINT