title: A population-based study of the clinical course of chronic fatigue syndrome.
abstract: BACKGROUND
  Chronic fatigue syndrome (CFS) presents a challenge for patients, health care providers, and health insurance groups because of its incapacitating nature, unknown cause, and poorly understood prognosis. We conducted a longitudinal population-based study to characterize the clinical course of CFS.
  
  
  METHODS
  Sixty-five CFS subjects were identified from a random-digit-dialing survey of Wichita, Kansas residents and followed for up to 3 years. We evaluated changes in CFS classification (partial or total remission, alternative medical or psychiatric diagnoses), CFS case-defining criteria, wellness scores, hours of activities and sleep, and treatments used to reduce fatigue. Associations between risk factors and outcomes were determined by use of logistic regression and generalized estimating equations models.
  
  
  RESULTS
  Only 20%-33% of the subjects were classified as having CFS at follow-up, 56.9% ever experienced partial or total remission, 10% sustained total remission, and 23.1% received alternative diagnoses, of which 20% were sleep disorders. Higher fatigue severity scores and total number of symptoms were negatively associated with ever remitting. Duration of illness < or = 2 years was positively associated with sustained remission. Unrefreshing sleep persisted in at least 79% of the subjects across all periods but, as with most of the CFS symptoms, tended to be less frequent over time. The number of activities affected by fatigue decreased over time, while wellness scores increased. At any follow-up, more than 35% of subjects reporting reduced fatigue used complementary and alternative medicine therapies, and of those subjects, at least 50% thought these therapies were responsible for reducing their fatigue.
  
  
  CONCLUSIONS
  The clinical course of CFS was characterized by an intermittent pattern of relapse and remission. Remission rates documented by our population-based study were similar to those reported in clinical studies. Shorter illness duration was a significant predictor of sustained remission, and thus early detection of CFS is of utmost importance. The persistence of sleep complaints and identification of sleep disorders suggest that CFS subjects be evaluated for sleep disturbances, which could be treated.
authors: Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. ran7@cdc.gov
authors: Rosane
authors: R
authors: Nisenbaum
authors: James F
authors: JF
authors: Jones
authors: Elizabeth R
authors: ER
authors: Unger
authors: Michele
authors: M
authors: Reyes
authors: William C
authors: WC
authors: Reeves
mesh_terms: D000328:Adult; D000368:Aged; D003627:Data Interpretation, Statistical; D015673:Fatigue Syndrome, Chronic / Q000145:classification* / Q000150:complications / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D007615:Kansas; D008297:Male; D008875:Middle Aged; D012075:Remission, Spontaneous; D012720:Severity of Illness Index; D017678:Sex Distribution; D012893:Sleep Wake Disorders / Q000150:complications; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires