Systemic Exertion Intolerance Disease (SEID).
The mysterious disease known as chronic fatigue syndrome (CFS) has long defied classification, because the symptoms vary greatly in the millions of people who are affected by it. Now, a panel commissioned by the US Department of Health and Human Services (HHS) has produced what is sure to be an influential report on how the disease should be diagnosed. The guidelines come with a new moniker: systemic exertion intolerance disease (SEID).
The report, released by the US Institute of Medicine (IOM) on 10 February, says that the new name better reflects the key symptom of the disease, the body’s inability to tolerate any exertion. It argues that other symptoms, such as cognitive impairment, are secondary. But some experts are already challenging the changes.
Leonard Jason, a psychologist at DePaul University in Chicago, Illinois, expects that patient advocacy groups will find fault with the name, and feel that they were not adequately consulted. “As a community psychologist who values citizen participation in critical decisions, I think this was a strategic mistake,” he says.
By contrast, members of the IOM panel say that the name should help people who are affected by the disease, the existence of which has long been doubted and even mocked. “If I never hear another person say ’I’m chronically fatigued too’, it won’t be too soon,” says committee chair Ellen Wright Clayton, an expert on law and genetics at Vanderbilt University in Nashville, Tennessee.
Research has shown that even many physicians are sceptical about the existence of CFS, and most do not know how to diagnose it. More specific criteria should address that problem. “That will in the end get more people cared for and treated,” says Peter Rowe, a paediatrician and chronic-fatigue expert at Johns Hopkins Children’s Center in Baltimore, Maryland, and a member of the IOM panel.
The report also attempts to simplify the diagnostic criteria, addressing concerns that previous definitions were too complex. For instance, people who have a mental illness can be diagnosed with SEID; they had been excluded from a CFS diagnosis because fatigue is also a symptom of depression.
Patients and researchers are universally thrilled about one aspect of the report: its definitive statement that the disease is real, not psychological. It even recommends that SEID be entered into the International Classification of Diseases, the book that physicians around the world use to make diagnoses. A patient at the IOM press conference described that as “the best thing that’s happened to me” since her CFS diagnosis years ago.
Still, Derek Enlander, a physician in New York City who specializes in chronic fatigue syndrome, worries that the revised criteria are too broad, and will result in too many patients being diagnosed. And the new name, he says, is bound to confuse patients, physicians and researchers, especially those who are not familiar with the condition.
Enlander says that the HHS, which spent US$1 million on the report, is likely to adopt the new definition. But the debate over the diagnostic criteria is sure to continue. “This is round one,” Jason says.
The prevalence of fibromyalgia varied by as much as fourfold, depending on which of three different American College of Rheumatology diagnostic criteria sets was used, a new study reveals.
The findings were published online January 28 in Arthritis & Rheumatology by Gareth T. Jones, PhD, from the University of Aberdeen, United Kingdom, and colleagues.
The investigators compared the 1990 American College of Rheumatology fibromyalgia classification criteria, the 2010 American College of Rheumatology preliminary diagnostic criteria, and the modified 2010 American College of Rheumatology criteria in 104 individuals who had scored positively for possible fibromyalgia on screening questionnaires and were subsequently examined.
The 1990 criteria include a history of chronic widespread pain plus pain on digital palpation in 11 or more of 18 specific sites.
The 2010 provisional classification differed from the 1990 definition by operationalizing the measurement of chronic widespread pain and by eliminating the requirement for a tender point exam, substituting an assessment of fatigue, waking unrefreshed, cognitive symptoms, and somatic symptoms in general. A patient is classified as having fibromyalgia if he or she has high levels of pain plus moderate levels of symptoms or moderate levels of pain plus high levels of symptoms, symptoms present at a similar level for 3 months, and no disorder that would otherwise explain the pain.
In 2011, a modification of the 2010 criteria was proposed that relies on self-reported pain and a simplified self-reported version of somatic symptoms for use in clinical and epidemiologic studies.
Of the 104 study participants, 31% met at least one of the three ACR fibromyalgia criteria: 11 met the 1990 definition, 7 met the 2010 criteria, and 27 met the modified 2010 criteria. There was not a lot of overlap, as only four individuals (12.5%) met all three sets of criteria and only nine (28%) met more than one.
Overall, the prevalence of fibromyalgia was 1.7% (95% confidence interval [CI], 0.7% – 2.8%) with the 1990 criteria, 1.2% (95% CI, 0.3% – 2.1%) with the 2010 criteria, and 5.4% (95% CI, 4.7% – 6.1%) with the modified 2010 criteria. Moreover, the female:male ratios were 13.7:1 for the 1990, 4.8:1 for the 2010, and 2.3:1 for the modified 2010 criteria.
“The current study is the first to compare all 3 sets of classification criteria in a general population sample, and our findings do not support previous claims that the modified 2010 criteria do not result in inflated prevalence estimates,” Dr Jones and colleagues write.
In addition to identifying a greater proportion of men, the modified 2010 criteria also appear to be influenced more by somatic symptoms than by pain, they note.
“Most importantly, operationalization of any new criteria must be clear and unambiguous, as well as immediately implementable. This is not currently the case. Both the ACR 2010 criteria and the ACR modified 2010 criteria are currently considered ‘preliminary,’ and we strongly recommend that the ACR consider these important issues in deciding whether to confirm these proposed criteria for use in future clinical practice and/or research,” they conclude.
This study was supported by the University of Aberdeen Development Trust. The authors have disclosed no relevant financial relationships.