Time Trends in Thyroid Hormone Changes Following Bariatric Surgery: A Systematic Review and Meta-Analysis

Area of Science:

• Endocrinology
• Metabolic Surgery
• Obesity Medicine

Background:

• Bariatric surgery's impact on thyroid function is variable.
• Obesity affects thyroid hormone levels and metabolism.
• Understanding postsurgical thyroid changes is crucial for patient management.

Purpose of the Study:

• To conduct a meta-analysis on time-dependent changes in thyroid hormones after bariatric surgery.
• To evaluate alterations in TSH, FT4, and FT3 levels in patients with obesity.

Main Methods:

• Systematic literature search of PubMed, Embase, and Scopus databases.
• Meta-analysis of 57 observational studies (8,030 participants) with random-effects modeling.
• Meta-regression and subgroup analyses to assess influencing factors.

Main Results:

• Significant reductions in TSH and FT3 observed at 6 months and 1 year post-surgery.
• Reductions in TSH and FT3 became non-significant beyond 1 year.
• No significant changes in FT4 levels were noted across follow-up periods.

Conclusions:

• Bariatric surgery induces significant, but temporary, reductions in TSH and FT3.
• FT4 levels remain largely unchanged post-bariatric surgery.
• Further research is needed to elucidate mechanisms and optimize thyroid health.