Adverse outcomes in patients with hypothyroidism undergoing bariatric surgery: A retrospective study using TriNetX

Context Bariatric surgery (BS) effectively reduces obesity-related risks, but its outcomes in patients with preexisting hypothyroidism are unclear. Objective To evaluate the impact of preexisting hypothyroidism on adverse health outcomes following BS. Design A retrospective cohort study utilizing the TriNetX Global Collaborative Network database. Setting Healthcare organizations. Patients Patients with obesity who underwent BS or not, with and without hypothyroidism were propensity score-matched. Exposure Treated hypothyroidism versus healthy thyroid. Main outcome measures The short-term outcomes comprised mortality, readmission, ICU admission, and surgical and systemic complications. The long-term outcomes included mortality, major adverse events, bone health, and metabolic, renal, and neurological outcomes. Results There were 5,700 patients in each cohort (46.7±12 years, 88% female). In the short term, patients with hypothyroidism exhibited higher risks of readmission (RR:1.25;CI:1.14-1.36), incisional hernia (RR:1.56;CI:1.12-2.18), and biliary diseases (RR:1.39;CI:1.05-1.86). In the long term, patients with hypothyroidism had higher risks of incident cerebrovascular events (HR:1.25;CI:1.00-1.55), diabetes (HR:1.39;CI:1.12-1.74), and dyslipidemia (HR:1.20;CI:1.02-1.42). There were also higher risks of fall (HR:1.20;CI:1.02-1.40), osteoporosis (HR:1.30;CI:1.07-1.58), polyneuropathy (HR:1.34;CI:1.08-1.66), hypoglycemia (HR:1.51;CI:1.23-1.87), as well as iron (HR:1.17;CI:1.04-1.31) and vitamin B (HR:1.34;CI:1.20-1.49) deficiencies. Hypothyroidism-associated risks of poor outcomes were higher in patients who underwent gastric bypass. Compared to the nonsurgical care, patients with hypothyroidism who underwent BS showed a lower risk of obesity-related outcomes but a higher risk of iron and vitamin B deficiencies, osteoporosis, and hypoglycemia. Conclusion Preexisting hypothyroidism in bariatric patients increases the risks of adverse outcomes. However, the risk of obesity-related outcomes is decreased in this population when compared to nonsurgical care.