Re: Body weight change is unpredictable after total thyroidectomy

Abstract

Re: Body weight change is unpredictable after total thyroidectomyWe read with interest the article by Glick et al. 1 assessing predictors for body weight change after total thyroidectomy in 79 patients. They found no predictors and in particular preoperative thyroid status did not predict weight gain after surgery. This observation is in contradiction with a larger study performed by Bel Lassen et al. 2 comparing weight gain after total thyroidectomy for multi-nodular goitre between patients with preoperative euthyroidism (n = 151) and with subclinical hyperthyroidism (n = 74). Body mass index gain was significantly greater in the subclinical hyperthyroid group than in the euthyroid group (1.11 AE 0.17 versus 0.33 AE 0.16 kg/ m 2 ; P = 0.003) and in the multivariate analysis, the preoperative serum TSH value was the main predictive factor for the increase in body weight.Methodological factors may explain why TSH or thyroid status did not predict weight change in the study of Glick et al.(1) The low number of patients and the heterogeneity of the preoperative diagnosis: patients with Graves' disease have probably been treated by antithyroid drugs preoperatively which makes it difficult to interpret thyroid status; patients with a diagnosis of thyroid cancer may have been psychologically affected and may have modified their diet. In our study, we included only patients with benign multi-nodular goitre free of treatment (antithyroid drug or thyroxine). (2) The definition of preoperative hyperthyroidism: TSH <0.3 mU/L is a consensual definition but patients treated with antithyroid drugs means that patients treated with antithyroid drug have been classified as hyperthyroid even with normal TSH value. (3) In the post-operative period, patients have been largely undertreated (mean TSH >5 mU/L). Therefore, we believe that the data presented in the article by Glick et al. do not allow to draw conclusions on possible predictors for weight change after thyroidectomy. References 1. Glick R, Chang P, Michail P, Serpell JW, Grodski S, Lee JC. Body weight change is unpredictable after total thyroidectomy. ANZ J. Surg. 2018; 88: 162-6. 2. Bel Lassen P, Kyrilli A, Lytrivi M, Ruiz Patino M, Corvilain B. Total thyroidectomy: a clue to understanding the metabolic changes induced by subclinical hyperthyroidism?Response to Re: Body weight change is unpredictable after total thyroidectomyWe thank Bel Lassen et al. 1 for their interest in our publication. 2 We also congratulate them for their work on this topic. 3 We acknowledge the concerns raised by Bel Lassen et al. 1 regarding patient numbers and heterogeneity (both surgical indication and treatment status). These limitations have been acknowledged within the manuscript.We appreciate Bel Lassen et al. pointing out the finding that post-operatively, on average, patients seemed to have been undertreated with thyroxine. In fact, patients without postoperative weight gain were far more undertreated (mean TSH: 5.9) than those who gained weight (mean TSH: 2.9). This finding is counteri...