Background: There are few data on the natural history and prognosis of persons with chronic fatigue (CF) or CF syndrome (CFS). Therefore, we compared functional outcomes in patients with each condition and tested the validity of various prognostic indicators.
Methods: Four hundred forty-five (89%) of 498 consecutive referral patients were surveyed an average of 1.5 years after an initial evaluation. Data from the initial evaluation were used to predict outcomes.
Results: Sixty-four percent of all patients reported improvement, but only 2% reported complete resolution of symptoms. Patients initially diagnosed as having CFS reported greater symptom severity and lower level of functioning at follow-up than did patients with CF. Major depression predicted unemployment in the CF group. Older age, longer duration of illness, and a lifetime history of dysthymia predicted less improvement in the CF group. Current dysthymia predicted less improvement for the CFS group.
Conclusions: The case definition of CFS according to the Centers for Disease Control and Prevention identifies chronically fatigued patients with poorer prognosis. In a tertiary care setting, recovery from CF or CFS is rare, but improvement is common. Prognostic indicators vary for the two groups, but the coexistence of dysthymia suggests poorer outcomes generally.