Body weight change is unpredictable after total thyroidectomy

Thyroidectomy Effects on the Body Mass Index and Thyroid-Stimulating Hormone: A Systematic Review and Meta-Analysis

Thyroidectomy is common and is performed for malignancy, goiters with pressure symptoms, and certain types of Grave's disease. Weight and body mass index (BMI) following thyroidectomy were discussed controversially. This meta-analysis aimed to assess weight and BMI following thyroidectomy. A systematic literature search was conducted in PubMed, Medline, and Google Scholar with interest in articles that assessed body weight and BMI following total or subtotal thyroidectomy. The search engine was limited to the period from inception up to January 2024. Keywords "total thyroidectomy", "subtotal thyroidectomy", "Graves' disease", "multinodular goiter", "differentiated thyroid carcinoma", and "toxic nodules" were used. Out of the 634 articles retrieved, 89 full texts were screened, and only six studies (five retrospective and one prospective cohort) fulfilled the inclusion and exclusion criteria. No differences were evident regarding weight and BMI before and after thyroidectomy (odds ratio: -0.63, 95%CI: -1.50 to -0.24, P-value for the overall effect: 0.15; and odds ratio: -0.12, 95% CI: -0.41 to -0.16, P-value for the overall effect: 0.40 respectively). No heterogeneity was observed (I2 for heterogeneity: 0.0%). No association between thyroidectomy (when performed for differentiated thyroid carcinoma and hyperthyroidism), weight, and BMI was found. Further studies assessing thyroid-stimulating hormone (TSH) levels, radioactive iodine therapy, and thyroxine dose are needed.

Body composition changes following total thyroidectomy: A one-year follow-up study

INTRODUCTION

Thyroid hormones play an important role in body weight regulation. In this study, we investigated which body composition parameters cause a change in body weight after total thyroidectomy.

MATERIALS AND METHOD

We performed a retrospective cohort study of a prospectively maintained database of patients who underwent total thyroidectomy. Demographics, thyroid function tests, indications for surgery, final pathology, and postoperative thyroid status were collected. Body composition analyses measured by the bioelectrical impedance analysis method were recorded at two-time points, 12 months apart.

RESULTS

Forty-four patients were included in the study with a mean age of 51.6 years. There were statistically significant increases in weight (p=0.049), body mass index (p=0.021), and fat mass (p=0.001) over time. While 12 patients (27.3%) lost or maintained weight, 32 patients (72.7%) gained weight. There was no significant difference in age, sex, preoperative thyroid function tests, postoperative thyroid status, or pathology between those who gained weight and those who did not. Although changes in all body composition parameters were higher in males than in females, these differences were not significant overall. Multivariable regression analysis revealed a significant positive relationship between increase in fat mass and baseline free-T₃ (p=0.041) and found that lower baseline percent body fat was a significant factor for greater fat mass gain (p=0.016). However, no predictors of change in weight were identified.

CONCLUSION

We conclude that total thyroidectomy results in a significant change in body weight and fat mass. Higher free-T₃ and lower percent body fat at baseline were significant factors of fat mass gain.

Weight Gain and Asthenia Following Thyroidectomy: Current Knowledge from Literature Review

BACKGROUND

Thyroidectomy is a common procedure all over the world. Its complication rate is low, but some patients complain of weight gain and/or asthenia. The aim of this review is to investigate the correlation between thyroidectomy and weight change and asthenia.

MATERIALS AND METHODS

Seven papers concerning weight gain and four concerning asthenia were found.

RESULTS

Weight gain would seem to be more related to the change in habits after surgery. Asthenia seems to be more linked to endocrine mechanisms not yet clarified although a deficiency of triiodothyronine and its metabolites could explain some of its aspects.

CONCLUSION

Patients who are candidates for thyroidectomy should be adequately informed of the onset of both possible implications of the surgical act in terms of weight gain and chronic asthenia.

Association between Thyroid Cancer and Weight Change: A Longitudinal Follow-Up Study

BACKGROUND

The purpose of this study was to evaluate body mass index (BMI) and systolic blood pressure (SBP)/diastolic blood pressure (DBP) between Korean adults who underwent thyroidectomy and comparison groups.

METHODS

Data were included from the Korean National Health Insurance Service-Health Screening Cohort (2002-2015). BMI and SBP/DBP were measured before thyroidectomy, 1 and 2 years after thyroidectomy (n = 1995 in study I, n = 2162 in study II), comparing 1:4 matched participants (n = 7980 in study I, n = 8648 in study II). The paired t-test and linear mixed model were used to identify the differences between groups.

RESULTS

DBP in both thyroid cancer II and comparison II group were significantly lower after thyroidectomy than before thyroidectomy. However, the interaction effect of thyroidectomy in study I and study II did not reach statistical significance.

CONCLUSION

BMI, SBP and DBP were not significantly different between the thyroidectomy group and the matched comparison group.

Weight Gain After Thyroidectomy: A Systematic Review and Meta-Analysis

CONTEXT

Weight gain is a major driver of dissatisfaction and decreased quality of life in patients with hypothyroidism. Data on the changes in body weight following thyroidectomy are conflicting.

OBJECTIVE

To perform a systematic review of the literature and a meta-analysis of weight changes following total thyroidectomy.

DATA SOURCES

Literature search on PubMed.

STUDY SELECTION

Studies in English published between September 1998 and May 2018 reporting post-thyroidectomy weight changes.

DATA EXTRACTION

Data were reviewed and compared by 3 investigators; discrepancies were resolved by consensus. Meta-analyses were performed using fixed and random effect models. Univariable and multivariable meta-regression models for weight change were implemented against study follow-up, gender, and age. Exploratory subgroup analyses were performed for indication for surgery.

DATA SYNTHESIS

Seventeen studies (3164 patients) with 23.8 ± 23.6 months follow-up were included. Severe heterogeneity across studies was observed. Using a random effect model, the estimated overall weight change was a gain of 2.13 kg, 95% confidence interval (CI; 0.95, 3.30). Age was negatively associated with weight change (β = -0.238, P < 0.001). In subgroup analyses, weight gain was more evident in patients undergoing thyroidectomy for hyperthyroidism: 5.19 kg, 95% CI (3.21, 7.17) vs goiter or malignancy 1.55 kg, 95% CI (0.82, 2.27) and 1.30 kg, 95% CI (0.45, 2.15), respectively.

CONCLUSIONS

Patients undergoing thyroidectomy experience possible mild weight gain, particularly younger individuals and those with hyperthyroidism as the indication for surgery. Prospective studies directed to assess the pathophysiology of weight gain post-thyroidectomy, and to test novel treatment modalities, are needed to better characterize post-thyroidectomy weight changes.

Weight change in patients with differentiated thyroid carcinoma after total thyroidectomy versus lobectomy

Purpose

Thyroid hormone is an important hormone in maintaining metabolism and homeostasis in the body. There exists a common perception among patients that thyroid surgery will cause weight gain. Prevention of any undesired weight gain could be important for the maintenance of well-being in most patients. Our study compares changes in body mass index (BMI) and weight after total thyroidectomy or lobectomy in thyroid cancer patients.

Methods

A total of 967 patients with differentiated thyroid carcinoma were enrolled in the study, from March 2011 to July 2016 at Chung-Ang University Hospital. Exclusion criteria were less than lobectomy, modified radical neck dissection, recurred operation, and combined operation for other causes. Primary endpoints were change in body weight and BMI at 2 years after surgery. A subgroup analysis was performed for patients with significant weight change.

Results

There were no differences between both groups in BMI after 2 years of thyroid operation. Thyroid stimulating hormone (TSH) levels were not significantly different. Fifteen percent of patients showed significant change in body weight after 2 years of operation. The subgroup analysis of these patients showed no significant differences in gender, age, or extent of operation between those who had gained weight compared to those who had lost weight. There were also no differences in postoperative TSH levels, levothyroxine supplementation, or radioactive iodine treatment.

Conclusion

There was a minimal postoperative increase in mean BMI over the years in patients undergoing thyroidectomy for differentiated thyroid cancer. However, weight change did not differ in those undergoing thyroid lobectomy or total thyroidectomy.

Weight gain following treatment of hyperthyroidism-A forgotten tale

Hyperthyroidism causes weight loss in the majority, but its effect is variable and 10% of patients gain weight. Its treatment usually leads to weight gain and some studies have reported an excess weight regain. However, there is considerable inter-individual variability and a differential effect on body weight by different treatments, with some studies reporting more weight increase with radioiodine, and perhaps surgery, compared with anti-thyroid drugs. The excess weight regain may relate to treatment-induced hypothyroidism. Furthermore, the transition from hyperthyroidism to euthyroidism may unmask, or exacerbate, the predisposition that some patients have towards obesity. Other risk factors commonly implicated for such weight increase include the severity of thyrotoxicosis at presentation and underlying Graves' disease. Conflicting data exist whether lean body mass or fat mass or both are increased post-therapy and whether such increments occur concurrently or in a sequential manner; this merits clarification. In any case, clinicians need to counsel their patients regarding this issue at presentation. Limited data on the effect of dietary interventions on weight changes with treatment of hyperthyroidism are encouraging in that they cause significantly lesser weight gain compared to standard care. More research is indicated on the impact of the treatment of hyperthyroidism on various anthropometric indices and the predisposing factors for any excessive weight gain. Regarding the impact of dietary management or other weight loss interventions, there is a need for well-designed and, ideally, controlled intervention studies.