Body weight changes in a large cohort of patients subjected to thyroidectomy for a wide spectrum of thyroid diseases.

OBJECTIVE: Patients undergoing thyroidectomy often complain of weight gain. The aim of this study was to longitudinally evaluate body-weight changes in patients thyroidectomized for euthyroid and hyperthyroid conditions in order to identify predictive factors.

METHODS: Anthropometric data and thyroid function parameters were retrospectively reviewed for 267 thyroidectomized patients before and 40 to 60 days and 9 months after surgery. Presurgery diagnoses included benign (Graves disease, nodular toxic goiter, nodular nontoxic goiter) and malignant (differentiated thyroid cancer) conditions.

RESULTS: Mean preintervention weight of the entire study group significantly increased (P<.0001) 9-months after thyroidectomy, from 70.8 ± 16.0 to 72.5 ± 16.4 kg. Body weight increased in 156 (58.4%) patients, decreased in 59 (22.1%) patients, and remained stable in 52 (19.5%) patients. A multiple regression model was constructed by entering the percentage of body-weight change 9 months postsurgery as the dependent variable and age, sex, presurgery body mass index, percentage of weight change 40 to 60 days postsurgery, presurgery thyroid-stimulating hormone (TSH) level, TSH level 40 to 60 days postsurgery, TSH level 9 months postsurgery, thyroid disease driving thyroidectomy, and type of surgical intervention as the covariates. No significant relationship was found for any of the covariates tested, with the exception of percentage of body-weight change at 40 to 60 days postsurgery (correlation coefficient, 0.869; [95% confidence interval, 0.692 to 1.046; P<.0001]).

CONCLUSION: Thyroidectomy is associated with a significant increase in body weight, which is not limited to patients with Graves disease. Postsurgery TSH levels do not account for subsequent body-weight changes. Short-term changes (40 to 60 days postsurgery) in body weight are highly predictive of the outcome at 9 months, suggesting that early factors related to thyroidectomy per se might play a role.