Evolution of subclinical hypothyroidism and its relation with glucose and triglycerides levels in morbidly obese patients after undergoing sleeve gastrectomy as bariatric procedure

BACKGROUND

There is an increased prevalence of subclinical hypothyroidism (SCH) in patients with obesity. It is unclear if this biochemical abnormality may be a secondary phenomenon of obesity or a real hypothyroid state.

METHODS

A retrospective study of all the morbidly obese patients undergoing laparoscopic sleeve gastrectomy as bariatric procedure between October 2007 and November 2012 was performed. Weight loss, body mass index (BMI) and excess weight loss, baseline glucose, lipid profiles, and TSH levels were obtained before operation and postoperative determinations at 3, 6, and 12 months after surgery.

RESULTS

Sixty patients were included. Prevalence of subclinical hypothyroidism was 16.7% preoperatively, 10% at 3 months, 3.3% at 6 months, and 1.7% at 12 months. A significant correlation could be established between TSH decrease and weight loss at 12 months (Pearson 0.603; p = 0.007). TSH decrease showed a significant correlation with glucose and glycated hemoglobin decrease from 6th month onwards. Referring to lipid profile, an association of TSH decrease with total cholesterol, LDL cholesterol, or HDL cholesterol could not be determined. A significant association between TSH decrease and triglycerides and cardiovascular risk index triglycerides/HDL cholesterol reductions could also be established 12 months after surgery.

CONCLUSIONS

SCH is usually corrected after bariatric surgery, while there are no significant changes in total or LDL cholesterol. This suggests that, in morbidly obese subjects, SCH is, in most patients, just a consequence of the abnormal fat accumulation and not a real hypothyroid state.