Pediatric Increased Risk and Nonlinear Age‐Dependent Risk of Hypoparathyroidism After Total Thyroidectomy: A 1914‐Patient Cohort Study

BACKGROUND: Post-thyroidectomy hypoparathyroidism is the most common complication of total thyroidectomy and a key indicator of surgical quality. The influence of age on postoperative risk, across the spectrum from pediatric to adult patients, remains incompletely defined. METHODS: Retrospective cohort study of 1914 consecutive patients undergoing primary total thyroidectomy for Graves' disease or differentiated thyroid carcinoma at a high-volume center, comprising 87 pediatric (< 18 years) and 1827 adult (≥ 18 years) patients operated on by the same endocrine surgical team. Transient and permanent hypoparathyroidism were defined according to the 2025 ESES/AAES/IAES consensus, with permanent disease confirmed biochemically beyond 12 months. Multivariable models were adjusted for surgical indication and lymph node dissection; within adults, age was modeled with restricted cubic splines followed by an age-band analysis. Pediatric histopathology was reviewed for inadvertent parathyroid excision. RESULTS: Transient hypoparathyroidism occurred in 29.9% of pediatric and 17.2% of adult patients (P = 0.004) and permanent hypoparathyroidism in 3.4% and 0.4% (P = 0.011). After adjustment, pediatric age remained independently associated with transient (OR 1.86, 95% CI 1.15-3.01) and permanent hypoparathyroidism (OR 5.74, 95% CI 1.35-20.02). Other surgical complications did not differ between groups. Inadvertent parathyroid excision was uncommon and accounted for only 1 pediatric hypoparathyroidism case, implicating devascularization rather than gland removal. Among adults, age showed a non-linear association with transient hypoparathyroidism, with increased risk at 40-50 years (OR 1.50, 95% CI 1.15-1.96; P = 0.003), particularly in differentiated thyroid carcinoma. CONCLUSIONS: Pediatric patients undergoing primary total thyroidectomy are at increased risk of postoperative hypoparathyroidism independent of surgical indication and extent, even under uniform high-volume surgical conditions, with devascularization the likely mechanism. In adults, risk varies non-linearly with age. These findings support age as a determinant of postoperative endocrine outcomes.