Adverse Outcomes in Patients With Hypothyroidism Undergoing Bariatric Surgery: A Retrospective Study Using TriNetX

Bariatric surgery (BS) effectively reduces obesity-related risks, but its outcomes in patients with preexisting hypothyroidism are unclear.

To evaluate the impact of preexisting hypothyroidism on adverse health outcomes following BS.

In this retrospective cohort study utilizing the TriNetX Global Collaborative Network database, patients with obesity who underwent BS or not, with and without hypothyroidism, were propensity score-matched. Short-term outcomes comprised mortality, readmission, ICU admission, and surgical and systemic complications. Long-term outcomes included mortality, major adverse events, bone health, and metabolic, renal, and neurological outcomes.

There were 5700 patients in each cohort (46.7 ± 12 years, 88% female). In the short term, patients with hypothyroidism exhibited higher risks of readmission (risk ratio [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 (hazard ratio [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.

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.