The impact of weight reduction following laparoscopic sleeve gastrectomy on thyroid-stimulating hormone level in obese patients with subclinical hypothyroidism: A 3-year retrospective study

Background: The effect of weight-reducing surgeries on thyroid function in morbid obese patients was evaluated byseveral studies. However, because of the variability of the techniques and the degrees of hypothyroidism, their resultswere inconsistent. So, our aim in this study was to evaluate the effect of laparoscopic sleeve gastrectomy (LSG) on thyroidfunction in obese patients with subclinical hypothyroidism (SH) seeking weight reduction as it is considered the mostcommon weight-reducing surgery performed and compare its results with malabsorptive procedures.Patients and Methods: This is a retrospective study evaluating all obese patients that underwent different weightreducingprocedures with a preoperative diagnosis of SH from June 2020 to June 2023, evaluating the thyroid function inobese patients after surgery.Results: One hundred thirty-four (9.3%) out of the 1450 morbidly obese patients that underwent LSG (82/813), Rouxen-Y gastric bypass (RYGB) (41/397) and mini-gastric bypass (MGB) (11/240) during the study period were found tohave SH during the preoperative investigations. Hypothyroidism improved in 50 (60.9%) patients and completely resolvedin 20 (24.3%) patients, while 11 (13.4%) patients experienced no improvement, and one (1.4%) patient developed overthypothyroidism following LSG after 1 year of follow up. Hypothyroidism improved in 16 (39%) patients and completelyresolved in 23 (56%) patients, while two (5%) patients experienced no improvement following RYGB after 1 year offollow-up. Hypothyroidism improved in four (36.3%) patients and completely resolved in six (54.5%) patients, while one(9.2%) patient experienced no improvement following MGB after 1 year of follow-up. The mean excess weight loss after1 year of surgery was 43.7% after LSG, 49.2% after RYGB, and 50.1% after MGB.Conclusion: Obesity itself has a significant impact on thyroid function, and different bariatric surgeries produce asignificant improvement of SH.