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

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.

Critical Approach to Hypothyroid Patients With Persistent Symptoms

Hypothyroidism is a common condition, and numerous studies have been published over the last decade to assess the potential risks associated with this disorder when inappropriately treated. The standard of care for treatment of hypothyroidism remains levothyroxine (LT4) at doses to achieve biochemical and clinical euthyroidism. However, about 15% of hypothyroid patients experience residual hypothyroid symptoms. Some population-based studies and international population-based surveys have confirmed dissatisfaction with LT4 treatment in some hypothyroid patients. It is well established that hypothyroid patients treated with LT4 exhibit higher serum thyroxine:triiodothyronine ratios and can have a persistent increase in cardiovascular risk factors. Moreover, variants in deiodinases and thyroid hormone transporter genes have been associated with subnormal T3 concentrations, persistent symptoms in LT4-treated patients, and improvement in response to the addition of liothyronine to LT4 therapy. The American (ATA) and European Thyroid Association (ETA) guidelines have recently evolved in their recognition of the potential limitations of LT4. This shift is reflected in prescribing patterns: Physicians' use of combination therapy is prevalent and possibly increasing. Randomized clinical trials have recently been published and, while they have found no improvement in treating hypothyroid patients, a number of important limitations did not allow generalizability. Meta-analyses have reported a preference rate for combination therapy in 46.2% hypothyroid patients treated with LT4. To promote discussions about an optimal study design, the ATA, ETA, and British Thyroid Association have recently published a consensus document. Our study provides a useful counterpoint on the controversial benefits of treating hypothyroid patients with combination therapy.

Pre-surgery dietician counseling can prevent post-thyroidectomy body weight gain: results of an intervention trial

PURPOSE

It is widely accepted that patients experience weight gain after total thyroidectomy, and preventive measures should be recommended.

METHODS

A prospective study was designed to assess the efficacy of a dietetic intervention to prevent post-thyroidectomy weight gain in patients undergoing surgery for both benign and malignant thyroid conditions. Patients undergoing total thyroidectomy were prospectively and randomly assigned to receive a personalized pre-surgery diet counseling (GROUP A) or no intervention (GROUP B), according to a 1:2 ratio. All patients underwent follow-up with body-weight measurement, thyroid function evaluation and lifestyle and eating habits assessment at baseline (T0), 45 days (T1) and 12 months (T2) post-surgery.

RESULTS

The final study group encompassed 30 patients in Group A and 58 patients in Group B. The two groups were similar in terms of age, sex, pre-surgery BMI, thyroid function and underlying thyroid condition. The evaluation of body weight variations showed that patients in Group A did not experience significant body weight changes at either T1 (p = 0.127) nor T2 (p = 0.890). At difference, patients in Group B underwent a significant body weight increase from T0 to both T1 (p = 0.009) and T2 (p = 0.009). TSH levels were similar in the two groups, both at T1 and T2. Lifestyle and eating habits questionnaires failed to register any significant difference between the two groups, apart from an increase in sweetened beverages consumption in Group B.

CONCLUSIONS

A dietician counseling is effective in preventing the post-thyroidectomy weight gain. Further studies in larger series of patients with a longer follow-up appear worthwhile.

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.

Total Thyroidectomy and Subsequent Weight Gain in Pediatric Populations

OBJECTIVE

To evaluate weight gain in children post-thyroidectomy and identify predictors.

METHODS

Charts from patients at a tertiary health care facility who underwent total thyroidectomy from 2014 to 2020 were reviewed for Body Mass Index z-scores (BMIz) at the time of thyroidectomy and at 1 and 2-year post-operation intervals. Patient demographic information, comorbidities, pre- and postoperative thyroid stimulating hormone, and postoperative free T4 levels were also extracted. Patients with other known endocrine abnormalities, chronic kidney disease, or without sufficient follow-up were excluded.

RESULTS

A total of 56 patients (ages 3-17 years old) met the inclusion criteria (n = 17 Graves' disease; n = 39 presumed cancer). Over the first year, average BMIz significantly increased in patients with Graves' disease (∆BMIz = 0.45 ± 0.77, p = 0.03), Hispanic ethnicity (∆BMIz = 0.43 ± 0.68, p = 0.004), Medicaid/no insurance coverage (∆BMIz = 0.33 ± 0.74, p = 0.038), age <13 years at thyroidectomy (∆BMIz = 0.35 ± 0.68, p = 0.016), and persistent postoperative hypothyroidism (∆BMIz = 0.41 ± 0.41, p = 0.012). These changes remained significant after the second year. Age at thyroidectomy correlated negatively with ∆BMIz only after the first year (r = -0.40, p = 0.002). Regression analysis, controlling for Graves' status, persistent postoperative hypothyroidism, and insurance coverage, identified age at thyroidectomy as a significant predictor of ∆BMIz after the first year (b = -0.06, p = 0.004) and Hispanic ethnicity as a significant predictor after the second year (b = 0.60, p = 0.003).

CONCLUSION

A small increase in BMIz post-thyroidectomy was observed across several patient subgroups. Younger age at thyroidectomy and Hispanic ethnicity were associated with increased BMIz in the first 2 years post-thyroidectomy.

LEVEL OF EVIDENCE

Level 4 - Historically controlled cohort Laryngoscope, 133:1518-1523, 2023.

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.

Duration of antithyroid drug treatment may predict weight gain after radioactive iodine therapy in patients with Graves' disease

Background

Weight gain post-radioiodine (RAI) treatment is observed in patients with hyperthyroid Graves’ disease. Previous studies, mostly in Caucasian patients, demonstrated excessive weight gain averaging 5–7 kg from initial presentation.

Aim

The aim of this study was to determine the extent and risk factors of weight gain in Thai patients with RAI-treated Graves’ disease.

Methods

This was a 5-year retrospective study of patients with hyperthyroid Graves’ disease who received RAI treatment during 2016–2020. The proportion and associated risk factors of weight gain ≥5% in patients who was followed for at least 3 months when compared with weight at RAI administration were analyzed.

Results

There were 347 patients with Graves’ disease (females 81.0%, mean age 38.8 ± 12.1 years, BMI 23.3 ± 4.0 kg/m²) who were treated with RAI. Almost all RAI-treated patients (91.9%) eventually developed hypothyroidism. During the median follow-up period of 25 months, 73.1% of them had weight gain. The mean weight change was +2.5 ± 4.9 kgs when compared with weight at the time RAI administration and +3.4 ± 6.5 kgs when compared with recalled body weight before the onset of hyperthyroidism. The proportion of patient in the obesity class I (BMI 25.0–29.9 kg/m²) increased from 23.6% to 28.0% and obesity class II (BMI ≥30.0 kg/m²) increased from 5.2% to 8.9%. Duration of antithyroid drug treatment less than 6 months after the diagnosis of hyperthyroidism was the only factor associated with weight gain ≥5%.

Conclusions

Weight gain post-RAI treatment was common, and a significant proportion of patients went on to develop obesity. Early intervention with weight management support should be employed in patients with less than 6 months of antithyroid drug treatment before RAI.

Inflammasome activation as a link between obesity and thyroid disorders: Implications for an integrated clinical management

Obesity is strongly associated with chronic low-grade inflammation. Obese patients have an increased risk to develop thyroid autoimmunity and to became hypothyroid, suggesting a pathogenetic link between obesity, inflammation and autoimmunity. Moreover, type 2 diabetes and dyslipidemia, also characterized by low-grade inflammation, were recently associated with more aggressive forms of Graves' ophthalmopathy. The association between obesity and autoimmune thyroid disorders may also go in the opposite direction, as treating autoimmune hyper and hypothyroidism can lead to weight gain. In addition, restoration of euthyroidism by L-T4 replacement therapy is more challenging in obese athyreotic patients, as it is difficult to maintain thyrotropin stimulation hormone (TSH) values within the normal range. Intriguingly, pro-inflammatory cytokines decrease in obese patients after bariatric surgery along with TSH levels. Moreover, the risk of thyroid cancer is increased in patients with thyroid autoimmune disorders, and is also related to the degree of obesity and inflammation. Molecular studies have shown a relationship between the low-grade inflammation of obesity and the activity of intracellular multiprotein complexes typical of immune cells (inflammasomes). We will now highlight some clinical implications of inflammasome activation in the relationship between obesity and thyroid disease.