CONTACT: BECKY SOGLIN
2130 Medical Laboratories
Iowa City IA 52242
(319) 335-6660; fax (319) 335-8034
Release: Jan. 11, 2000
UI study helps clarify chronic fatigue definition and prognostic factors
IOWA CITY, Iowa -- People with chronic fatigue usually don't know why they
have the fatigue, when they will get better or how to treat the fatigue. However,
a recent University of Iowa study identifies prognostic characteristics for
improvement of chronic fatigue.
The study found that certain patient characteristics helped predict which
individuals with chronic fatigue would improve, said Arthur J. Hartz, M.D.,
Ph.D., UI professor of family medicine and the study's principal investigator
and lead author. The study also raised questions about the current definition
of chronic fatigue syndrome, a subclassification of unexplained chronic fatigue.
"We found that only some of the symptoms used to define chronic fatigue
syndrome provide information about fatigue prognosis," said Hartz, who
is also director of research in the UI department of family medicine.
In contrast to previous studies, the UI-led investigation examined patients
who had idiopathic, or unexplained, chronic fatigue rather than only patients
with the more narrowly labeled chronic fatigue syndrome. As a result, the
study was able to compare the prognoses for chronic fatigue patients who had
certain factors to the prognoses for chronic fatigue patients who did not
have these factors.
"Most researchers have assumed that there is a special type of chronic
fatigue called chronic fatigue syndrome," explained Hartz. "But
there has been little empirical basis for the definition, making it somewhat
subjective. It's important to better subclassify chronic fatigue for both
research and clinical care purposes."
Unexplained chronic fatigue substantially impairs a person's quality of
life but has no known medical or lifestyle cause. The investigators found
that people with poor memory or poor concentration and symptoms not currently
used to define chronic fatigue syndrome -- including backaches, indigestion,
other stomach or intestinal problems or discomfort, mild fever or chills,
dizziness and unexplained muscle weakness -- were less likely to recover from
The investigation also showed that less frequent sleep disruption, fewer
hours sleeping overall and being married were also associated with fatigue
The study involved 199 Wisconsin patients with unexplained chronic fatigue
lasting six or more months. The UI team collaborated with investigators at
the Medical College of Wisconsin in Milwaukee and the George Washington School
of Public Health in Washington, D.C.
The researchers evaluated questionnaires completed by participants, primarily
women ages 30 to 55, to assess changes over a two-year period. Participants
included members of the Wisconsin Chronic Fatigue Syndrome Association.
Chronic fatigue syndrome was first defined in 1988, then redefined in 1994.
It is defined as idiopathic chronic fatigue plus any four of eight symptoms
-- despite the lack of empirical support for the definition, Hartz explained.
Those symptoms include: fatigue lasting more than 24 hours following exercise;
memory or concentration problems; tiredness upon waking in the morning; a
sore throat; tender cervical or axillary lymph nodes; muscle aches; joint
pain; and headaches.
Hartz said the lack of empirical evidence for chronic fatigue syndrome may
contribute to the lack of success in developing an effective laboratory test
to identify people with the condition.
"There are no hard findings," he said. "Periodically, a laboratory
test is reported to diagnose chronic fatigue syndrome, but so far these tests
have not been substantiated. It will be difficult to develop the test before
the condition is well defined."
Chronic fatigue is frustrating for patients and physicians alike because
patients often do not respond to medication, said Hartz, who also investigates
conventional and alternative treatment methods for unexplained chronic fatigue.
He noted that physicians sometimes assume chronic fatigue is simply depression.
The relationship between depression and fatigue has always been of great
interest, he said. "Although depression may cause fatigue, there is considerable
evidence that depression is not the cause for many people with unexplained
chronic fatigue," he said.
However, the UI-led study shows a linkage, Hartz added. Depression scores
improved for many patients whose fatigue improved, not just for those who
had been severely depressed.
"Although depression may underlie the fatigue for some patients, it
is also possible that the fatigue may underlie the depression, or a third
problem may underlie both," he said. "When this other problem improves,
both the fatigue and depression may improve."
Hartz concluded, "The more information we have to classify patients
with chronic fatigue, the better able we will be to focus the research, which
can lead to improved clinical care."
The chronic fatigue findings appeared in the November/December issue of
the Archives of Family Medicine. In addition to Hartz, the UI research team
included Suzanne Bentler, research associate in family medicine.
The study was funded in part by a grant from the American Academy of Family
University of Iowa Health Care describes the partnership between the
UI College of Medicine and the UI Hospitals and Clinics and the patient care,
medical education and research programs and services they provide.