I asked CDC's Unger via email why is CDC using the antiquated
Oxford* definition in its partnership with HRSA (Health Resources and Services
Administration), along with Fukuda** and Canadian Consensus Criteria*** in its continuing education courses? The Oxford definition
requires only fatigue, unlike the other definitions of ME, which require
immune, neurologic and autonomic symptoms.
I also asked Unger:
- For
most CFS-literate physicians and patients, using all three definitions is
a problem. That’s because the Oxford definition requires only fatigue as a
symptom. In contrast, Fukuda requires fatigue and four other symptoms.* According to most CFS-literate physicians, the Canadian Consensus
Criteria (CCC) is the most accurate and thorough of these three
definitions, and requires the following: fatigue, post-exertional malaise
and/or fatigue, sleep dysfunction, and pain; two or more
neurological/cognitive manifestations and one or more symptoms from two of
the categories of autonomic, neuroendocrine and immune manifestations.**
Given the significant differences in
definitions, does CDC believe using all three definitions is problematic?
Why or why not?
- By
focusing on fatigue, the Oxford definition neglects other important
symptoms embraced by CCC, as well as other symptoms in the original Fukuda
definition. Fatigue is characteristic of many illnesses, from cancer and
heart disease to depression. Thus, with the Oxford definition, CFS
morphs into a vague disease—it’s only vague by the Oxford definition, not
by CCC. Using the Oxford definition makes it more difficult for
doctors to distinguish pathological fatigue of CFS from ordinary fatigue
and from illnesses that have fatigue as a symptom—and that’s most
illnesses. For all these reasons, Oxford is, in the view of most patients
and CFS-literate physicians, a woefully inadequate and inaccurate
definition. Does CDC understand the problems with the Oxford definition?
- Does
CDC want there to be confusion about the disease?
- If
CDC doesn’t want there to be confusion, why does it use all three vastly
different definitions in the HRSA CME courses?
- Over
and over again, CDC states in meetings and in its medical articles that
CFS is a poorly understood disease. Other researchers and clinicians look
to CDC for guidance. Does CDC understand that by using all three of these
vastly different definitions, CDC is causing the disease to be poorly
understood?
- The
CCC definition describes the illness that most patients and CFS-literate
physicians understand to be CFS. Given that using multiple definitions
results in confusion and heterogeneous populations, why not make this
critical change and use only CCC? Please explain why CDC won’t do
this.
CDC’s Response
Through its press office, CDC—I assume it was Unger, since I directed my questions to
her—replied:
CDC has
developed several CFS CME courses, including Diagnosis and Management of
Chronic Fatigue Syndrome (see http://www.cdc.gov/cfs/education/diagnosis/index.html) which was prepared in collaboration
with other CFS subject matter experts, including non-CDC clinicians in private
practice and academic settings. Among other things, this CDC CME course
provides information about multiple CFS case definitions, such as those
mentioned in your query. CDC uses the 1994 case definition, but recognizes
there are additional case definitions that can be useful. CDC is committed to
providing accurate, evidence-based CFS information that is relevant to various
audiences, including CFS patients, clinicians who treat CFS patients,
researchers, and others.
I believe this information
addresses the questions you asked. You may wish to contact HRSA directly
about questions regarding CME courses produced by that agency.
Thank you for your interest
in CDC’s CFS research program.
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-------------------
*Oxford definition
fatigue as the main symptom; definite onset and not lifelong; fatigue is severe, disabling and affects physical and mental function; fatigue should persist for 6 months or more and be present 50% of the time; other symptoms, especially myalgia, sleep and mood disturbance may be present.
**Fukuda definition:
Patients must have four of the following:
Self-reported impairment in short term
memory or concentration severe enough to cause substantial reduction in
previous levels of occupational, educational, social, or personal activities;
sore throat; tender cervical or axillary lymph nodes; muscle pain; multi-joint
pain without swelling or redness; headaches of a new type, pattern or severity;
unrefreshing sleep; post-exertional malaise (PEM) lasting more than 24 hours.
***
Canadian Consensus Criteria:
Neurological/Cognitive Manifestations:
Two or more of the following: confusion, impairment of concentration and
short-term memory consolidation, disorientation, difficulty within formation
processing, categorizing and word retrieval, and perceptual and sensory
disturbances—e.g., spatial instability and disorientation and inability to
focus vision. Ataxia, muscle weakness and fasciculations are common. There may
be overload phenomena: cognitive, sensory—e.g., photophobia and
hypersensitivity to noise—and/or emotional overload, which may lead to crash
periods and/or anxiety.
One or more symptoms from two of the
categories of autonomic, neuroendocrine and immune manifestations:
Autonomic Manifestations: orthostatic
intolerance neurally mediated hypotension (NMH), postural orthostatic
tachycardia syndrome (POTS), delayed postural hypotension; light-headedness;
extreme pallor; nausea and irritable bowel syndrome; urinary frequency and bladder
dysfunction; palpitations with or without cardiac arrhythmias; exertional
dyspnea.
Neuroendocrine Manifestations: loss
of thermostatic stability—subnormal body temperature and marked diurnal
fluctuation, sweating episodes, recurrent feelings of feverishness and cold
extremities; intolerance of extremes of heat and cold; marked weight
change—anorexia or abnormal appetite; loss of adaptability and worsening of
symptoms with stress.
Immune Manifestations: tender lymph
nodes, recurrent sore throat, recurrent flu-like symptoms, general malaise, new
sensitivities to food, medications and/or chemicals.