Wichita Clinical Study

The Wichita Clinical Study was a research study conducted by William Reeves and his CFS program department at the Centers for Disease Control & Prevention. From December 2002 to July 2003 in Wichita, Kansas, USA, a 2-day in-hospital clinical assessment study was undertaken. The main objective of the study was to characterize the physiologic status of subjects with CFS, and to test the application of the 1994 CFS criteria to standardized reproducible criteria.

The complete data set is available on the CDC Wichita Clinical Study Data Access website.

The study enrolled 227 people and classified them into five study groups based on specific criteria:


 * CFS group - patients who met the 1994 CFS international case definition, also known as the Fukuda criteria case definition
 * CFS-MDDm group - patients who met the 1994 CFS international case definition except that a major depressive disorder with melancholic features was identified
 * ISF group - patients who are chronically fatigued but not meeting the CFS case definition because of insufficient number of symptoms or fatigue severity
 * ISF-MDDm group - patients who are chronically fatigued but with an insufficient number of symptoms or fatigue severity and a major depressive disorder with melancholic features
 * NF group - patients who are non-fatigued controls matched to CFS subjects on age, race/ethnicity, sex, and body mass index

The conclusion of the Wichita Clinical Study published in 2005 stated: "The empirical definition includes all aspects of CFS specified in the 1994 case definition and identifies persons with CFS in a precise manner that can be readily reproduced by both investigators and clinicians."

In 2006, Reeves spoke at The National Press Club as part of a Chronic Fatigue Syndrome Awareness Campaign. Using results from the Wichita Clinical Study, he stated:"When we completed the medical workups of people in Wichita to confirm that they had CFS, we found that only half of those with the illness had consulted a physician for the illness. We found that only 16 percent had been diagnosed and treated for CFS...We found that a quarter of the people with CFS are either unemployed or receiving disability...We’ve documented, as have others, that the level of functional impairment in people who suffer from CFS is comparable to multiple sclerosis, AIDS, end-stage renal failure, [or] chronic obstructive pulmonary disease. The disability is equivalent to that of some well-known, very severe medical conditions.”