AACE ePoster Library

Introduction: The standard of care for treatment of patients with autoimmune thyroiditis is repletion with levothyroxine to within the “normal” range. This is known to prevent serious complications of hypothyroidism including weight gain, and at the extreme, myxedema coma. While the normal TSH range includes the 95% confidence intervals, it is not known if there is an association between weight and TSH when the TSH is within this interval. Although patients often associate even treated hypothyroidism with difficulty losing weight, our hypothesis is that there is no difference in BMI between healthy controls versus those with treated hypothyroidism with similar TSH. We did speculate that patients with treated hypothyroidism with a TSH in the upper half of normal would have a BMI greater than those with treated hypothyroidism and a TSH in the lower half of the normal range.

Methods: We conducted a chart review of patients seen within the Cooper Health System from January 1 to August 31, 2014. The initial group of 878 treated hypothyroid patients and 386 euthyroid controls was culled to 250 treated hypothyroid patients and 163 euthyroid controls, after exclusions. Data collected included age (18-60 years-old included in the study), gender, race, height, weight, diabetes history, smoking history, and for those on treatment, type and dose of thyroid hormone. The data was analyzed for significance using Welch-Satterthwaite analysis, pooled analysis, and Fisher’s exact test.

Results: Hypothyroid and control groups were similar in height, weight, BMI, and number of diabetic patients. There were more females, Caucasians, and non-smokers in the hypothyroid group. The average TSH was slightly higher in the treated hypothyroid patients versus the non-hypothyroid controls (2.06 v. 1.73, P < 0.01). There was no significant relationship between TSH and BMI in the treated hypothyroid patients or the euthyroid controls (BMI did not increase with increasing TSH within the normal range).

Conclusion: The fact that there is no significant relationship between BMI and TSH in patients with treated hypothyroidism suggests that there may not be a benefit in terms of weight reduction in keeping the TSH in hypothyroid patients in the lower half of the normal range. In addition, patients should be counseled that hypothyroidism, if properly treated, is unlikely to significantly contribute to weight gain. Other factors, such as nutrition and exercise counseling, should be offered to these patients.