Effectiveness of Bariatric Surgery for Improving Thyroid Function and Reducing Levothyroxine Dose in Patients With Obesity and Overt Hypothyroidism

Background: Hypothyroidism is a major hormonal condition that affects more women than men in Saudi Arabia. Studies indicate a bidirectional link between hypothyroidism and obesity, which may improve following bariatric surgery (BS). The focus of this research is to assess how hypothyroidism patients' thyroid function and levothyroxine dosage are impacted by bariatric surgery. Methodology: This was an observational retrospective study conducted in two centres at Taif, Saudi Arabia. All morbidly obese patients who were diagnosed with overt hypothyroidism and underwent laparoscopic sleeve gastrectomy from January 2016 to December 2021 were included. The changes in the thyroid profile and the changes in the doses or cessation of levothyroxine were evaluated after the laparoscopic sleeve gastrectomy. Results: Our results demonstrate that a total of 70 patients dominated by women out of 1202 from both centers who meet our inclusion criteria showed a statistically significant decrease on comparison of clinical parameters (thyroid-stimulating hormone [TSH], free T4 [FT4], free T3 [FT3], levothyroxine [L-T4]) before and after BS. The average TSH levels were determined to be 4.45 ± 4.41 mIU/L prior to BS, and they significantly decreased (3.17 ± 2.77 mIU/L) following BS (p=0.009). When compared to before BS (13.17 ± 2.73 pmol/L), the mean FT4 levels after BS (11.63 ± 5.88 pmol/L) exhibited a significant decline (p=0.046). The mean FT3 levels before and after BS also were statistically significantly lower (1.94 ± 2.12 pg/mL) than before (2.75 ± 1.96 pg/mL), p=0.009. The mean L-T4 levels after BS considerably decreased from before BS (98.68 ± 56.18 mcg) to after BS (79.39 ± 41.49 mcg), p=0.046. Conclusion: Better thyroid profiles and lower levothyroxine dosage show that bariatric surgery improves hypothyroidism.