Body weight change is unpredictable after total thyroidectomy

Background: There is a common perception that total thyroidectomy causes weight gain beyond expected age-related changes, even when thyroid replacement therapy induces a euthyroid state. The aim of this study was to determine whether patients who underwent total thyroidectomy for a wide spectrum of conditions experienced weight gain following surgery. Methods: We retrospectively studied 107 consecutive total thyroidectomy patients treated between January 2013 and June 2014. Medical records were reviewed to determine underlying pathology, thyroid status, use of antithyroid drugs and preoperative weight. Follow-up data were obtained from 79 patients at least 10 months post-operatively to determine current weight, the type of clinician managing thyroid replacement therapy and patient satisfaction with post-thyroidectomy management. Results: The cohort was 73% female, with a mean age of 55.8 ± 15.7 years and a mean preoperative weight of 78.8 ± 17.5 kg. Commonest pathologies were multinodular goitre, Graves' disease, thyroid cancer and Hashimoto's thyroiditis. Preoperatively, 63.2% of patients were hyperthyroid. Mean weight change at follow-up was a non-significant increase of 0.06 ± 6.9 kg (P = 0.094). Weight change was not significant regardless of preoperative thyroid function status. This study did not demonstrate any significant differences in clinical characteristics (including post-operative thyroid-stimulating hormone) between the group with >2% weight gain and those who did not. Conclusions: This study did not reveal significant weight gain following thyroidectomy for a wide spectrum of pathologies. Specifically, preoperative hyperthyroidism, female gender and use of antithyroid medications do not predict weight gain after thyroid surgery.