Iatrogenic Subclinical Hyperthyroidism Does Not Promote Weight Loss

Among patients who have undergone total thyroidectomy, do those with thyroid cancer being kept iatrogenically subclinical hyperthyroid (SCH) differ from euthyroid patients in long-term weight change?

In a retrospective study, medical records identified 291 patients who had undergone a thyroidectomy for differentiated thyroid cancer or benign thyroid disease. Weight, thyroid-stimulating hormone, and levothyroxine dose were measured presurgery and 1, 2, and 3 years postsurgery.

Of 291 patients, 147 were in the SCH group and 144 were in the euthyroid group. At all 3 years both groups gained weight from baseline, but the two groups did not differ in weight change from baseline at any time period: year 1 (SCH mean 0.4% ± 6.2% weight gain vs euthyroid group mean 2.2% ± 6.6% weight gain; P = 0.12), year 2 (SCH mean 1.1% ± 9.1% weight gain vs euthyroid mean 2.9% ± 7.8% weight gain; P = 0.22), and year 3 (SCH mean 2.6% ± 9.2% weight gain vs euthyroid mean 3.1% ± 11.1% weight gain; P = 0.49).

Among total thyroidectomy patients, weight change did not differ between SCH patients and euthyroid patients at years 1 through 3. As such, the use of levothyroxine to induce SCH did not lead to long-term weight change when compared with euthyroid patients.