The prevalence and possible significance of thyroid disorders to Chronic Fatigue Syndrome patients diagnosed in CFS specialty clinics.
*Lucinda Bateman, Nancy Klimas, Daniel Peterson, Susan M. Levine, Donna Felsenstein, Gail H. Ironson and the CFI Study Group**
Objectives:
Examine the occurrence and/or treatment of thyroid conditions in CFS patients diagnosed in CFS specialty clinics.
Methods:
Data from the Chronic Fatigue Initiative (CFI) were analyzed to assess how many patients are diagnosed with a thyroid condition, taking levothyroxine, and/or have abnormal thyroid stimulating hormone (TSH) results compared to age, gender and regionally matched healthy control subjects.
The study cohort has 405 subjects, 203 with CFS and 202 matched controls, divided evenly across five CFS Clinics in the U.S (Salt Lake City, Miami, Incline Village, New York, Boston), collected between Dec 2011 and Dec 2012
Results:
Hypothyroidism is listed as a diagnosis in 30% versus 7% (p=.000), hyperthyroidism in 3% versus 0% (p = .014), and thyroiditis in 7% versus 0% (p = .001) of CFS patients versus matched healthy controls.
Levothyroxine is taken by 23% of CFS patients versus 5% of controls.
Of all subjects on levothyroxine (n=51), 23 reported they are significantly improved, 16 somewhat improved, 12 unchanged, and no one reported being somewhat worse or significantly worse on this treatment.
There was no difference in effectiveness of levothyroxine for CFS patients (n=42) vs. controls (n=9). (The effectiveness data are from the medication history in the core questionnaire).
TSH lab values are available from 199 CFS and 199 control subjects.
There is no difference between the mean TSH values of CFS patients and controls (including 42 CFS patients and 9 Control subjects taking levothyroxine).
Of the total cohort (on or off levothyroxine) 14% of the CFS patients had abnormal TSH (16 low, 12 high) and 7% of the health controls had abnormal TSH (7 low and 7 high).
Conclusions:
The diagnosis of thyroid disorders and treatment with thyroid hormone is much higher in CFS patients than the normal population.
This may be from the detection and treatment of subclinical hypothyroidism (defined as a TSH 5-10 with normal T4) during a vigorous diagnostic search for underlying chronic illness, but the background rate in the general population is 3-8%, as is reflected in our control subjects.
It is possible that patients are receiving chronic thyroid hormone supplementation without a true diagnosis of thyroid disease in an attempt to treat CFS symptoms, a practice that does not have established long term efficacy or safety.
The data may also suggest an underlying mechanism of illness in CFS that leads to primary or secondary hypothyroidism.
Because the main causes of hypo- and hyperthyroidism in the general population are auto-immune, further analysis of these findings may lead to better understanding of CFS pathophysiology and to more effective treatments.
*Lucinda Bateman, MD. Director, Fatigue Consultation Clinic. 1002 E. South Temple, Suite 408, Salt Lake City, Utah 84108.
lbateman@fcclinic.com
**The CFI Cohort Recruitment Study Group includes:
Nancy Klimas, MD, Nova Southeastern University and Miami VA Hospital,
Lucinda Bateman, MD, Fatigue Consultation Clinic, SLC Utah
Dan Peterson, MD, Simmaron Research Institute, Nevada
Donna Felsenstein, MD, Harvard Medical School, Boston MA
Susan M. Levine, MD, New York City, NY
Anthony L. Komaroff, MD, Harvard Medical School, Boston MA
Mady Hornig, MD, Center for Infection and Immunity, Columbia University Mailman School of Public Health
W. Ian Lipkin, MD, Center for Infection and Immunity, Columbia University Mailman School of Public Health
Statistical team:
Gail Ironson, MD, PhD, University of Miami Elizabeth Balbin, University of Miami and Miami VA Hospital
Aundrea Carter, University of North Carolina, Greensboro
Korinne Chu, Physicians for Peace, Norfolk, VA
Serology
Mary Ann Fletcher, PhD, Nova Southeastern University and Miami VA Hospital