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Summer 2003 

Research News
The latest information on research, treatment and diagnosis of CFIDS and related disorders
Terms in bold type appear in the CFIDS Glossary box.

Dual treatment shows no benefit
A new study from Belgium reports that combining hydrocortisone and fludrocortisone therapy to treat CFS symptoms was not effective in a six-month trial.

Urine samples from many CFS patients show lower-than-normal levels of cortisol, a stress-related hormone also called hydrocortisone. It’s not known whether low cortisol is a cause of CFS symptoms, or an effect triggered by other abnormalities.

In the past, researchers have attempted to treat CFS symptoms by supplementing the body with hydrocortisone. The results have been mixed, and there have been reported side effects that include a suppression of natural cortisol production.

Fludrocortisone, a synthetic hormone known by the brand name Florinef, is sometimes used to treat orthostatic intolerance. But at least two previous studies have shown that Florinef does not significantly alleviate CFS symptoms.

The latest research involved 80 CFS patients who met the 1994 Fukuda criteria for CFS. The patients were given a daily treatment that included both fludrocortisone and hydrocortisone. The treatments were randomized and double-blinded over six months, so that neither the patients nor the researchers knew who was receiving the drugs and who was receiving a placebo treatment. After the treatment period, researchers found no difference between the treatment group and the placebo group in terms of patient-reported fatigue or overall well-being.

The study appeared in the June 15 issue of the American Journal of Medicine.

CFS-vaccine link probed
The Brighton Collaboration has launched an initiative to develop assessment guidelines for patients who have an onset of a CFS-like illness after being vaccinated.

An international working group of experts in CFS and vaccine safety has been assembled; Association President & CEO Kim Kenney is a member. The group will: conduct a literature review; define various levels of diagnostic certainty for evaluating possible CFS cases that follow vaccination; and write guidelines for data collection, analysis and presentation to enhance comparability across research and clinical settings. The process is expected to take about a year; all meetings are held by conference call.

The Brighton Collaboration was begun by the Centers for Disease Control and Prevention in 2001. So far, nine case definitions with guidelines have been written. CFS was selected as a topic based on sporadic reports of CFS-like illness following Rubella and hepatitis B vaccines. Brighton staff emphasize that the group’s interest in a particular condition does not imply a causal link between vaccines and that illness.

Wichita study reaches med journal
Research results from a large population-based study of CFS patients in Kansas have been published in an international medical journal.

In July, Archives of Internal Medicine featured a paper called “Prevalence and incidence of chronic fatigue syndrome in Wichita, Kan.” The multi-year study was conducted by the Centers for Disease Control and Prevention (CDC) in conjunction with other research teams.

In the study, more than 30,000 households were contacted and screened for people with CFS-like symptoms. Researchers gave questionnaires and/or medical examinations to a group of 7,162 residents, then re-checked their status after one year. The results showed that the overall rate of CFS in the general population is about 235 per 100,000 residents (95% confidence interval, 142–327).

The prevalence of CFS was higher among women (373 per 100,000) than men (83 per 100,000). These figures roughly correspond to earlier prevalence studies done on smaller groups. The new report concludes that “Chronic fatigue syndrome constitutes a major public health problem.”

The Wichita study began in 1997 and took four years to complete. CDC teams have recently conducted thorough medical examinations and numerous research tests on more than 400 city residents who were tracked during this period, including those with and without CFS. Results from these examinations are expected to be published over the next several years. Wichita was chosen as a test site because the makeup of its population is representative of the overall U.S. population.

“Intriguing” result from Lyndonville study
A new study related to the Lyndonville, N.Y., outbreak of CFS shows that environmental and genetic factors may combine to cause the illness in susceptible individuals.

The study looks at aspects of the immune systems in 90 people with CFS and 50 healthy controls. Included in the study were people from Lyndonville, where scores of residents developed CFS in the mid-1980s. Other subjects, who came from Buffalo, N.Y., were used for comparison.

Study authors said they discovered an “intriguing outcome” when looking at the cytotoxic T-cell levels in the patient groups. This type of T-cell attacks body cells that are infected or have become malignant. The CFS patients who lived in Lyndonville during the outbreak showed an increased level of the T-cells, as did the CFS patients from Buffalo.

But the non-CFS controls from Lyndonville also showed higher T-cell counts, while the non-CFS Buffalo controls did not.

This could indicate that some agent was present in Lyndonville that caused the residents’ immune systems to gear up for a fight. It’s possible, the authors say, that residents who developed CFS were predisposed in some unknown way to develop CFS, while those who remained healthy had the ability to fight off the illness.

The Buffalo residents with CFS may have been exposed to the same agents as the people in Lyndonville — although the whole city apparently did not receive the same exposure.

The study was published in the journal Cytometry Part B: Clinical Cytometry (53B, 2003).

CFIDS Glossary: Terms You Need to Know

Confidence interval: In statistics, a range of figures in which the true value being sought most likely resides. This is expressed in terms of percentage. The term “95 percent confidence interval” means that the true value will be within the given range 95 percent of the time.

For instance: A report says that 300 people out of 100,000 have CFS (95 percent confidence interval: 250-350). This means there’s a 95 percent chance that the figure is somewhere between 250 and 350 people.

Fukuda criteria: Another term for the 1994 International Research Case Definition of Chronic Fatigue Syndrome. This is the most commonly used criteria for identifying CFS cases for use in research studies. Although not originally intended for use by physicians to diagnose CFS in individual patients, it is often used for this purpose. Keiji Fukuda of the Centers for Disease Control and Prevention was the lead author of the definition.

Population-based study: As the name implies, a study that seeks information by looking at the residents of a particular geographic region. These studies can be particularly useful in determining the prevalence of a disease. By taking a representative sample of the population, scientists can imply how many people are affected by a given condition. This sampling method helps avoid conclusions that are biased by subjects’ differing access to medical care, as often occurs with clinic-based studies.

If you have suggestions for terms to include in future editions of the glossary, please send them to: chronicle@cfids.org, or to The CFIDS Association of America, P.O. Box 220398, Charlotte, NC 28222-0398, Attention: Chronicle.