title: Prevalence of fatigue and chronic fatigue syndrome in a primary care practice.
abstract: BACKGROUND
  Our goals were to determine the prevalence of unusual, debilitating fatigue and the frequency with which it was associated with the chronic fatigue syndrome (CFS) or other physical or psychological illness in an outpatient clinic population.
  
  
  METHODS
  We prospectively evaluated a cohort of 1000 consecutive patients in a primary care clinic in an urban, hospital-based general medicine practice. The study protocol included a detailed history, physical examination, and laboratory and psychiatric testing.
  
  
  RESULTS
  Five patients who came because of CFS studies were excluded. Of the remaining 995, 323 reported fatigue, and 271 (27%) complained of at least 6 months of unusual fatigue that interfered with their daily lives. Of the 271, self-report or record review revealed a medical or psychiatric condition that could have explained the fatigue in 186 (69%). Thus, 85 (8.5%) of 995 patients had a debilitating fatigue of at least 6 months' duration, without apparent cause. Of these patients, 48 refused further evaluation, and 11 were unavailable for follow-up; 26 completed the protocol. Three of the 26 were hypothyroid, and one had a major psychiatric disorder. Of the remaining 22 patients, three met Centers for Disease Control and Prevention criteria for CFS, four met British criteria, and 10 met the Australian case definition. The point prevalences of CFS were thus 0.3% (95% confidence interval [CI], 0% to 0.6%), 0.4% (95% CI, 0% to 0.8%), and 1.0% (95% CI, 0.4% to 1.6%) using the Centers for Disease Control and Prevention, British, and Australian case definitions, respectively. These estimates were conservative, because they assumed that none of the patients who refused evaluation or were unavailable for follow-up would meet criteria for CFS.
  
  
  CONCLUSIONS
  While chronic, debilitating fatigue is common in medical outpatients, CFS is relatively uncommon. Prevalence depends substantially on the case definition used.
authors.affiliation: Department of Medicine, Brigham and Women's Hospital, Boston, Mass.
authors.forename: D W
authors.initials: DW
authors.lastname: Bates
authors.forename: W
authors.initials: W
authors.lastname: Schmitt
authors.forename: D
authors.initials: D
authors.lastname: Buchwald
authors.forename: N C
authors.initials: NC
authors.lastname: Ware
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.forename: E
authors.initials: E
authors.lastname: Thoyer
authors.forename: R J
authors.initials: RJ
authors.lastname: Kornish
authors.forename: A L
authors.initials: AL
authors.lastname: Komaroff
mesh_terms: D000328:Adult; D000553:Ambulatory Care; D001315:Australia; D002487:Centers for Disease Control and Prevention, U.S.; D003937:Diagnosis, Differential; D005221:Fatigue / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008487:Medical History Taking; D008875:Middle Aged; D010808:Physical Examination; D015995:Prevalence; D011320:Primary Health Care; D011446:Prospective Studies; D011581:Psychological Tests; D006113:United Kingdom; D014481:United States