Clinical Thyroidology® for the Public
Summaries for the Public from recent articles in Clinical Thyroidology
Table of Contents | PDF File for Saving and Printing
HYPOTHYROIDISM
Thyroid hormone treatment after weight loss surgery
Clinical Thyroidology® for the Public
Summaries for the Public from recent articles in Clinical Thyroidology
Table of Contents | PDF File for Saving and Printing
HYPOTHYROIDISM
Thyroid hormone treatment after weight loss surgery
BACKGROUND
Hypothyroidism, or underactive thyroid, is treated by thyroid hormone replacement to return thyroid hormone levels to the normal range. In many cases, the dose of thyroid hormone required to treat hypothyroidism is related to the patient’s weights. Significant weight gain (ie 30-50+ pounds) can increase the thyroid hormone dose requirements. Similarly, significant weight loss can decrease the thyroid hormone dose needed to get the thyroid levels into the normal range. Weight loss/ bariatric surgery usually leads to significant weight loss relatively quickly after surgery. As such, weight loss surgery is frequently the best treatment for severe obesity with medial complications. The 2 most common types of bariatric surgery are sleeve gastrectomy (SG) and gastric bypass (GB). Along with the weight loss, patients with hypothyroidism frequently need to decrease their thyroid hormone dose.
This study was done to evaluate the change in thyroid hormone dosing in hypothyroid patients who are undergoing weight loss surgery.
THE FULL ARTICLE TITLE
Barzin M et al. Thyroid hormone replacement dosing after bariatric surgery in patients with primary hypothyroidism and severe obesity: Tehran Obesity Treatment Study. Thyroid. Epub 2024 Aug 19. doi: 10.1089/ thy.2024.0073. PMID: 39155815.
SUMMARY OF THE STUDY
A total of 1030 hypothyroid patients undergoing weight loss surgery were followed for 3 years. The study was called the Tehran Obesity Treatment Study. Thyroid hormone blood levels were measured before the surgery and at several points after surgery. All patients were treated with levothyroxine and the dose was calculated after each testing. Of the1030 hypothyroid patients, 707 had SG and 323 GB.
Overall, there was greater weight loss after GB than after SG. While TSH and T4 values did not change in the GB group, TSH levels decreased in the SG group over time. The overall average levothyroxine dose did not vary significantly after the third year in either group. However, it was shown that 56.1% of SG patients experienced a dose reduction, while only 33.3% of their GB counterparts did so. Surprisingly, 9.1% of patients that had SG and 24.4% of those that had GB had levothyroxine dose increases, while 34.8% of the SG patients and 42.2% pf GB patients stayed on a stable dose, respectively. In both groups, the levothyroxine doses returned to a stable level after the first year of follow-up.
WHAT ARE THE IMPLICATIONS OF THIS STUDY?
The results of this study show that thyroid hormone doses need to be adjusted in >50% of patients after weight loss surgery and are more common after sleeve gastrectomy than gastric bypass. Surprisingly, while most of the dose changes are a decrease in dose, as many as 25% of patients may need a dose increase. Also, most of the dose changes occur in the 1st year after surgery. Thus, it is important to keep adjustment of thyroid hormone dose in mind while patients lose significant weight during the first year after surgery.
— Vibhavasu Sharma, MD
ATA RESOURCES
Hypothyroidism (Underactive): https://www.thyroid.org/hypothyroidism/
Thyroid Hormone Treatment: https://www.thyroid.org/thyroid-hormone-treatment/
ABBREVIATIONS & DEFINITIONS
Hypothyroidism: a condition where the thyroid gland is underactive and doesn’t produce enough thyroid hormone. Treatment requires taking thyroid hormone pills.
Thyroid Hormone Therapy: patients with hypothyroidism are most often treated with Levothyroxine in order to return their thyroid hormone levels to normal
Bariatric Surgery: weight loss surgery that is very effective in patients with severe obesity and medical complications. The 2 most common types of bariatric surgery are sleeve gastrectomy and gastric bypass.