Chronic fatigue diagnosis

A new study on chronic fatigue syndrome may hold two lessons for healthcare providers.

Many patients should not be diagnosed with CFS because they have exclusionary psychiatric and medical conditions. And those who are properly diagnosed have a high rate of depression, anxiety and other psychiatric comorbidities.

"Based on our study, not all medical and psychiatry providers are familiar with all of the exclusionary conditions for CFS," Dr Ann Vincent, who led the study at the Mayo Clinic in Rochester, Minnesota.

"Fatigue has multiple causes that need to considered by a provider. Some of those causes will be exclusionary for a CFS diagnosis" according to the 1994-CFS case definition, Dr Vincent says.

The study "highlights the importance of a thorough psychiatric evaluation at the time of diagnosis so that clinical management can focus on identification and treatment of psychiatric disorders and decrease the overall symptom burden," she and her colleagues wrote in the abstract for a presentation to the American Psychiatric Association.

The study

The Centres for Disease Control and Prevention were also involved in the study, and a CDC researcher presented the results at the conference last week in Honolulu, Hawaii. Only Dr Vincent, however, was cleared to speak with the press.

Dr Vincent's team studied 686 patients seen from 1998-2002 who were diagnosed with CFS or had a symptom of fatigue coupled with muscle pain, sleep problems or other conditions.

They excluded 100 (14.5%) for psychiatric disorders and 510 (74.3%) for medical conditions that made them ineligible to meet the case definition for CFS.

For example, the psychiatric disorders included substance abuse within two years of the CFS diagnosis (7%) and bipolar disorder (4%). Examples of exclusionary medical conditions included obstructive sleep apnea and congestive heart failure, Dr Vincent says.

The researchers then placed the remaining patients into two groups. There were 52 who had CFS, and 24 who had "insufficient fatigue" (ISF), meaning they met some, but not all of the criteria for CFS.

By the numbers, depression afflicted 67% of the CFS group, 42% of the ISF group and 33% of age- and sex-matched controls (P=0.001). Anxiety affected 52% of the CSF group, 58% of the ISF group and 21% of controls (P<0.001).

"CFS cases, as compared to controls, had more depression and anxiety, which is similar to what is seen in many other chronic illness," Dr Vincent says.

Other disorders studied included somatoform disorder and dysthymia, but their rates did not differ significantly between the groups.

The patients studied are part of the Rochester Epidemiology Project, which pools medical records from providers and residents in Olmsted County, Minnesota, allowing for disease etiology and outcome studies in a defined population.

(Reuters Health, Rob Goodier, May 2011)

Read more:

Depression condition centre

Bipolar disorder

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