History of Roux-en-Y Gastric Bypass Increases Risk of Symptomatic Hypocalcemia After Total Thyroidectomy

Background: Roux-en-Y gastric bypass (RYGB) has been performed as a means for patients to lose weight through both a restrictive and malabsorptive process. This malabsorption can lead to nutritional deficiencies, especially those that require the duodenum for absorption. RYGB has been thought to increase the risk of hypocalcemia after total and completion thyroidectomy, although the literature remains limited. Methods: A retrospective cohort study was performed analyzing a high-volume endocrine surgery practice. Patients who had a history of RYGB and total or completion thyroidectomy were included. These patients were compared to controls who underwent the same procedures but did not have a history of RYGB. Rates of postoperative hypocalcemia, length of stay, emergency department visits, and readmissions were compared between groups. Categorical variables were compared with Fisher exact test or the chi-square test. Continuous variables were compared with Welch’s t-test and Mann–Whitney U test when appropriate. Results: There were 22 patients with a history of RYGB who underwent thyroidectomy compared to 551 controls. Patients with a history of RYGB had significantly lower preoperative calcium (p < 0.01) and significantly more postoperative transient symptomatic hypocalcemia (41% vs. 20%, p = 0.03). This was accompanied by a longer postoperative length of stay, and although not significant, there was a higher trend in emergency department visits and readmissions. Conclusions: Patients who undergo total thyroidectomy after RYGB are at an increased risk of transient hypocalcemia in the postoperative setting.