Hypocalcemia after thyroidectomy in patients with a history of bariatric surgery.

Background: Hypocalcemia is a common complication after total thyroidectomy. Previous bariatric surgery could be a higher factor risk for hypocalcemia due to alterations in calcium absorption and vitamin D deficiency.

Objectives: To evaluate incidence and factors involved in the risk of hypocalcemia (transient and permanent) and the postoperative outcomes of these patients after total thyroidectomy.

Setting: University hospital in Paris, France.

Methods: All patients who had previously undergone obesity surgery (i.e., Roux-en-Y gastric bypass, sleeve gastrectomy, or adjustable gastric band) who had a total thyroidectomy from 2006 to 2015 were included. No patient was lost to follow-up. Each patient was matched 1:1 with a patient who had no previous bariatric surgery for age, gender, body mass index, and year of surgery.

Results: Forty-eight patients were identified (43 female; mean age 48.9±9.2 yr). Nineteen patients (40%) had a postoperative hypocalcemia: transient in 14 patients (29.2%) and permanent in 5 patients (10.4%). No significant predictive clinical or biochemical factors were found for hypocalcemia risk, except for the type of bariatric procedure: Bypass surgery had a 2-fold increased risk of hypocalcemia compared to others procedures (60% versus 30%, P = .05). In the matched pair analysis, the risk of hypocalcemia was significantly higher in patients with previous bariatric surgery than in the matched cohort (40% versus 15%, P = .006).

Conclusion: Patients with previous bariatric surgery have an increased risk for hypocalcemia after total thyroidectomy, especially after Roux-en-Y gastric bypass. Careful and prolonged follow-up of calcium, vitamin D, and parathyroid hormone levels should be suggested for these patients.