Elsevier

Mayo Clinic Proceedings

Volume 87, Issue 12, December 2012, Pages 1145-1152
Mayo Clinic Proceedings

Original article
Prevalence, Incidence, and Classification of Chronic Fatigue Syndrome in Olmsted County, Minnesota, as Estimated Using the Rochester Epidemiology Project

https://doi.org/10.1016/j.mayocp.2012.08.015Get rights and content

Abstract

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

We conducted a retrospective medical record review of potential cases of chronic fatigue syndrome identified from January 1, 1998, through 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 that interfered with daily work or activities. Patients not meeting all of the criteria were classified as having insufficient/idiopathic fatigue.

Results

We identified 686 potential patients with chronic fatigue, 2 of whom declined consent for medical record review. Of the remaining 684 patients, 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 per 100,000 persons and 13.16 per 100,000 person-years vs 73.70 per 100,000 persons and 13.58 per 100,000 person-years, respectively. The potential cases included 482 patients (70%) who had an exclusionary condition, and almost half the patients who met either criterion had at least one nonexclusionary 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 comorbid conditions rather than chronic fatigue syndrome itself will ensure appropriate assessment for patients without chronic fatigue syndrome.

Section snippets

Patients and Methods

This study was approved by the institutional review boards of Mayo Clinic and Olmsted Medical Center. We reviewed the records of Olmsted County residents seen between 1998 and 2002 who participated in the REP and granted permission for review of their medical records.

Results

Using the medical indexing of the REP, we identified 686 possible cases of CFS based on ICD-9/H-ICDA codes (Figure). Two patients declined consent for medical record review; review of the medical records of the remaining 684 patients identified 482 (70%) with an exclusionary condition (Table 2). Of the remaining 202 patients, we classified 76 as meeting criteria for CFS, 75 as meeting criteria for ISF, and 51 as having neither (Figure). Of the 76 cases that met CFS criteria, 50 (66%) were

Discussion

We used ICD-9 and H-ICDA codes from the REP in conjunction with medical record review to classify patients with CFS according to international research criteria.1 The codes accurately identified 66% of patients with CFS, which reflects a high level of knowledge and awareness of CFS among health care professionals in Olmsted County. Of note, 70% of patients who met symptom criteria had a current exclusionary condition. The most common exclusionary conditions were obstructive sleep apnea,

Conclusion

We found that CFS and ISF could be identified by medical record review and that the incidence and prevalence of CFS and ISF are relatively low in the Olmsted County population but are within prevalence ranges cited in other studies. One explanation for the low incidence is identification of patients who fulfill diagnostic criteria for a syndrome but who have an underlying exclusionary disease process that is readily identifiable or that is evolving. Such an outcome may be attributed to the

Acknowledgments

The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the US Department of Health and Human Services, the US Food and Drug Administration, the Centers for Disease Control and Prevention, the Center for Translational Science Activities at Mayo Clinic, the National Center for Research Resources, or the National Institutes of Health.

Dr Vincent had full access to all the data in the study and takes responsibility for the integrity of the

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  • Cited by (0)

    Grant Support: This study was supported in part by grants from the Centers for Disease Control and Prevention (200-2009-M-32507, FP00055021·02), the Rochester Epidemiology Project (R01-AG034676; Principle Investigators: Walter A. Rocca, MD, MPH, and Barbara P. Yawn, MD, MSc), and the Center for Translational Science Activities at Mayo Clinic (this center is funded in part by a grant [RR024150] from the National Center for Research Resources, a component of the National Institutes of Health).

    Author Contributions: Ann Vincent, MD—Design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript. Dana J. Brimmer, PhD, MPH—Design and conduct of the study; analysis and interpretation of the data; and preparation, review, or approval of the manuscript. Mary O. Whipple, BA—Design and conduct of the study; collection, management, and preparation, review, or approval of the manuscript. James F. Jones, MD—Design and conduct of the study; interpretation of the data; and preparation, review, or approval of the manuscript. Roumiana Boneva, MD, PhD—Design and conduct of the study; interpretation of the data; and preparation, review, or approval of the manuscript. Brian D. Lahr, MS—Statistical analysis; interpretation of the data; and preparation, review, or approval of the manuscript. Elizabeth Maloney, DrPh, MS—Design and conduct of the study; interpretation of the data; and preparation, review, or approval of the manuscript. Jennifer L. St. Sauver, PhD—Design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript. William C. Reeves, MD, MS—Design and conduct of the study; interpretation of the data; and preparation, review, or approval of the manuscript.

    Dr Maloney is now with the Center for Drug Evaluation and Research, Office of Surveillance and Epidemiology, Division of Epidemiology II, US Food and Drug Administration, Silver Spring, MD. Dr Reeves is now with the Division of Behavioral Surveillance, Centers for Disease Control and Prevention, Atlanta, GA.

    Data Previously Presented: These data were presented in part at the annual meeting of the American Psychiatric Association, Honolulu, HI, May 14-19, 2011.

    Died [August 3, 2012].

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