CHRONIC FATIGUE AND THE CHRONIC-FATIGUE-SYNDROME - PREVALENCE IN A PACIFIC-NORTHWEST HEALTH-CARE SYSTEM

Objectives: To investigate the point prevalence of the chronic fatigue syndrome and unexplained debilitating chronic fatigue in a community- based sample of persons and to describe demographic, clinical, and psy chosocial differences among those with the chronic fatigue syndrome, t hose with chronic fatigue, and healthy controls. Design: Prospective c ohort study. Setting: A health maintenance organization in Seattle, Wa shington. Participants: A random sample of 4000 members of the health maintenance organization was surveyed by mail for the presence of chro nic fatigue. Measurements: Persons with chronic fatigue were evaluated using a questionnaire that requested information about medical histor y and fatigue and related symptoms; validated measures of functional s tatus and psychological distress; a physical examination; and standard ized blood tests. A structured psychiatric interview was done in perso ns who appeared to meet the original Centers for Disease Control and P revention (CDC) criteria for the chronic fatigue syndrome. Participant s completed self-report measures at 12 and 24 months. Those with chron ic fatigue were reevaluated in person 1 year after study enrollment. R esults. 3066 (77%) of the 4000 members surveyed responded. Chronic fat igue was reported by 590 persons (19%). Of these, 388 (66%) had a medi cal or psychiatric condition that could account for the fatigue. Of th e 74 persons (37%) with chronic fatigue who were enrolled in the study , only 3 met the CDC criteria for the chronic fatigue syndrome. The re maining 71 persons were designated as having chronic fatigue alone. Se venty-four healthy, age- and sex-matched controls who were drawn from the same sample but who denied having chronic fatigue were also studie d. Demographic characteristics were similar in persons with the chroni c fatigue syndrome, persons with chronic fatigue atone, and controls. Those with the chronic fatigue syndrome or chronic fatigue alone had m ore frequent cervical and axillary adenopathy, poorer functional statu s, and greater psychological distress than controls. Women and minorit ies were not overrepresented among cases with chronic fatigue. Conclus ions: Using different assumptions about the likelihood that persons wh o did not participate in the study had the chronic fatigue syndrome, t he estimated crude point prevalence of the syndrome in this community ranged from 75 to 267 cases per 100 000 persons. The point prevalence of chronic fatigue alone was strikingly higher; it ranged from 1775 to 6321 cases per 100 000 persons.