"Troubles of Chronic Fatigue Syndrome Start With Defining It" NYT

Discussion in 'Fibromyalgia Main Forum' started by tansy, Mar 5, 2011.

  1. tansy

    tansy New Member


    Published: March 4, 2011

    When reports emerged 30 years ago that young gay men were suffering
    from rare forms of pneumonia and cancer, public health investigators
    scrambled to understand what appeared to be a deadly immune disorder:
    What were the symptoms? Who was most susceptible? What kinds of
    infections were markers of the disease?

    They were seeking the epidemiologist’s most essential tool — an
    accurate case definition, a set of criteria that simultaneously
    include people with the illness and exclude those without it. With
    AIDS, investigators soon recognized that injection-drug users,
    hemophiliacs and other demographic groups were also at risk, and the
    case definition evolved over time to incorporate lab evidence of
    immune dysfunction and other refinements based on scientific advances.

    “If you recognize something is happening, you need a case definition
    so you can count it,” said Andrew Moss, an emeritus professor of
    epidemiology at the University of California, San Francisco, and an
    early AIDS investigator. “You need to know whether the numbers are
    going up or down, or whether treatment and prevention work. And if you
    have a bad case definition, then it’s very difficult to figure out
    what’s going on.”

    Once a disease can be diagnosed reliably through lab tests, creating
    an accurate case definition becomes easier. But when an ailment has no
    known cause and its symptoms are subjective — as with chronic fatigue
    syndrome, fibromyalgia and other diseases whose characteristics and
    even existence have been contested — competing case definitions are
    almost inevitable.

    Now a new study of chronic fatigue syndrome has highlighted how
    competing case definitions can lead to an epidemiologic “Rashomon” —
    what you see depends on who’s doing the looking — and has stoked a
    fierce debate among researchers and patient advocates on both sides of
    the Atlantic.

    The study, published last month in The Lancet, reported that exercise
    and cognitive-behavioral therapy could help people with the illness.
    Advocates and some leading experts dismissed the findings and said the
    authors’ case definition was largely to blame.

    The British scientists who conducted the research identified study
    participants based largely on a single symptom: disabling and
    unexplained fatigue lasting at least six months. But many researchers,
    especially in the United States, say that definition takes in many
    patients whose real illness is not the syndrome but depression — which
    can often be eased with psychotherapy and exercise.

    The Lancet authors “have written their case definition to include both
    people with major depressive disorders and patients who clearly have
    received an insult to their immune systems and are depressed because
    they can no longer do things that they used to,” said Dr. Andreas
    Kogelnik, an infectious disease specialist in Mountain View, Calif.,
    who treats many people with chronic fatigue syndrome.

    In studying the condition, he and other researchers exclude patients
    whose only symptom is fatigue, however disabling, and instead rely on
    a case definition that includes other cognitive, neurological and
    physiological symptoms. Those symptoms, they believe, indicate a
    complex immune system disorder possibly caused by a virus or another

    Since 2009, studies have produced contradictory results over whether
    viruses related to mouse leukemia are associated with chronic fatigue
    syndrome, which is also called myalgic encephalomyelitis. A recent
    study found that people with the illness have distinct proteins in
    their spinal fluid, raising hope that a diagnostic test can someday be

    No case definition is perfect; every disease has outliers. But whether
    a definition is broadly or narrowly drawn can profoundly affect the
    statistics vital for public health planning.

    A recent study of workers, for example, found that 2.5 percent to 11
    percent suffered from carpal tunnel syndrome, depending on whether the
    case definition required reported symptoms, a physical exam, a nerve
    test or a combination of the three. Another study found that rates of
    acute gastroenteritis doubled when a looser case definition was used.
    If researchers filter their perceptions through different lenses —
    that is, case definitions that generate study populations varying in
    size and characteristics — it is hard to know whether they are
    studying the same phenomenon, overlapping ones or completely unrelated
    ailments. Determining whether findings from one study can be
    extrapolated to other patients becomes difficult at best.

    “You have to really define the characteristics, and everybody has to
    use the same criteria, because otherwise you’re calling something an
    apple and someone else is really looking at a peach and calling it an
    apple,” said Dr. Anita Belman, a neurologist at Stony Brook University
    who conducts research on pediatric multiple sclerosis.

    No one disputes that many people with chronic fatigue syndrome also
    suffer from depression. The question is which came first. Are patients
    depressed because a terrible disease has robbed them of their lives,
    or is the illness itself a somatic expression of an underlying

    To researchers who believe that chronic fatigue syndrome is merely a
    psychological condition, that distinction may not seem important. But
    it matters deeply to those convinced it is a viral disease, who say
    the exercise therapy advised by the Lancet study can cause major
    relapses in people with chronic fatigue syndrome — a claim supported
    by some patient surveys.

    The single-symptom case definition used by the Lancet authors, known
    as the Oxford criteria, was developed in Britain in 1991. Like the
    team that conducted the current study, the 1991 group included
    prominent mental health professionals.

    But many scientists and clinicians view a multisymptom case definition
    published in 1994 by the Centers for Disease Control and Prevention in
    the United States as the international standard.

    In addition to six months of unexplained, disabling fatigue, the
    C.D.C. definition requires at least four of eight common symptoms:
    cognitive problems, sleep disorders, muscle pain, joint pain,
    headaches, tender lymph nodes, sore throat and what is called
    “postexertional malaise”— a relapse that occurs after even minimal

    In 2005, the agency unveiled an “empirical” case definition that
    recommended specific screening questionnaires and cutoff scores for
    measuring fatigue, physical dysfunction and other symptoms. Critics
    challenged these newer guidelines on the same grounds as the Oxford
    criteria, arguing that the questionnaires and scoring methods were too

    In contrast, a 2003 case definition from Canada is considered the most
    restrictive and is preferred by many patients. It elevates
    postexertional malaise to a central role in the illness and requires a
    range of neurological, cognitive, endocrine or immunological symptoms.
    In 2009, researchers from DePaul University in Chicago reported that
    38 percent of patients in a study sample suffering from depression
    alone were given misdiagnoses of chronic fatigue syndrome using the
    C.D.C. screening tools but not the narrower Canadian definition.

    The study suggests that the disease centers’ “empirical case
    definition has broadened the criteria such that some individuals with
    a purely psychiatric illness will be inappropriately diagnosed” with
    chronic fatigue syndrome, wrote Leonard A. Jason, a professor of
    community psychology at DePaul, and his colleagues. The authors also
    noted that using the new screening tools, the C.D.C. had greatly
    increased its estimate of the prevalence of the illness, to 2.5
    percent of the population, or four million Americans.

    So the question remains: can therapy and exercise help patients with
    chronic fatigue syndrome, as the Lancet study reported?

    Yes, apparently — if the illness is identified with a case definition
    relying on fatigue alone. But does the evidence from that study prove
    that these strategies would help patients identified as having chronic
    fatigue syndrome through very different criteria? That is a much
    tougher argument to make.
  2. quanked

    quanked Member

    A thorough examination of defining CFIDS/ME.

    In some ways, at least through my present mind fog and exhaustion, it seems pretty simple--everyone needs to be using the same definition to study a problem otherwise, as the article states, the studies will have some very different outcomes. I will not even dare go into biases of the researchers in the CFIDS/ME domain.

    This dd is sure getting a lot of press and it seems to be getting saner and more focused.
  3. mbofov

    mbofov Active Member

    Thanks, Tansy. A meaningful definition is crucial if we are ever going to make any progress toward understanding this dd, and I firmly believe that "post-exertional malaise" has to be central to any such definition. No other illness has bone-crushing fatigue whose onset occurs some 12 to 24 hours after exertion, and then lasts for days.

  4. tansy

    tansy New Member

    for research and trials on Tx is crucial if we are to move forward.

    Quanked it's not only necessary for researchers to use the same definition, it's also necessary for them to use one that does not rely on chronic fatigue for 6 months or more. Other chronic illnesses, life style factors, burn out, and mental health conditions cause chronic fatigue too.

    Mary I agree; many of us do not describe our PEM, and the exacerbation of classic symtpoms, as fatigue because they involve so much more.

    The construct of CFS has been our biggest hurdle.

    Take care, Tansy. x
    [This Message was Edited on 03/11/2011]
  5. slowdreamer

    slowdreamer New Member

    Great article thanks..Have been saying this stuff for yeaaars!!!

    I actually think some good (in Oz at least) will come out of the focus on the Pace trial..
    I was at the DOcs again...(burn is coming along nicely) and I think they are mostly getting it,,i.e. the diagnosis mixup..

    Also spoke to a young DOc who said

    "At Medical school we are taught to know everything but there is so much we don't know"

    ..She also said Tetanus vaccine was not an option..

    Also Tansy I went to a PSych last week who has had CFS herself... Conversation was on anothe r planet...and so very helpful.
  6. tansy

    tansy New Member

    That's good, was pleased to read your wound is healing and your psyh appt went well. The definition used in the UK for ther PACE trial isn't fit for purpose but brings financial and career rewards for those who insist on using it.
  7. tansy

    tansy New Member

    Studying a Fatigue Illness (1 Letter)


    followed by -

    "The writers are the principal investigators of the PACE trial.

    David Tuller replies: The article asked whether findings among a population defined by one set of criteria would apply to populations defined by “very different criteria.”

    In this study, all participants were first defined, identified and selected not by different criteria but by the same criteria, the so-called Oxford criteria used in Britain. Subgroups within that already screened population who also meet secondary criteria are not easily compared to patients who have not been screened, since an unknown number who met the secondary criteria might not have met the study’s criteria for inclusion.

    ***The gold standard for making comparisons across groups of patients identified by three varying case definitions would be a study with three completely separate cohorts, not one large sample with two embedded subgroups." ***

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