Objective
To estimate the prevalence and incidence of chronic fatigue syndrome in Olmsted County, Minnesota using the 1994 Case Definition and describe exclusionary and comorbid conditions observed in patients who presented for evaluation of long standing fatigue.
Patients and Methods
Retrospective chart review of potential cases identified from January 1, 1998- December 31, 2002 using the Rochester Epidemiology Project, a population-based database. Patients were classified as having chronic fatigue syndrome if the medical record review documented fatigue of 6 months’ duration, at least 4 of 8 chronic fatigue syndrome-defining symptoms, and symptoms interfered with daily work or activities. Patients not meeting all of the criteria were classified as “insufficient/idiopathic fatigue.”
Results
Of 686 potential patients identified, 151 (22%) met criteria for chronic fatigue syndrome or insufficient/idiopathic fatigue. The overall prevalence and incidence of chronic fatigue syndrome and insufficient/idiopathic fatigue were 71.34 and 13.16, and 73.70 and 13.58 per 100,000 persons, respectively. 70% of potential cases had an exclusionary condition and, almost half the patients who met either criterion had at least 1 non exclusionary comorbid condition.
Conclusion
The incidence and prevalence of chronic fatigue syndrome and insufficient/idiopathic fatigue are relatively low in Olmsted County. Careful clinical evaluation to identify whether fatigue could be attributed to exclusionary or co morbid conditions rather than chronic fatigue syndrome itself will ensure appropriate assessment for patients without chronic fatigue syndrome.