Risk and Protective Factors of Postoperative and Persistent Hypoparathyroidism after Total Thyroidectomy in a Series of 1965 Patients

Background: Postoperative hypoparathyroidism (HypoPTH) is the most common complication following total thyroidectomy. Several risk factors have been identified, but data on postoperative follow-up are scarce. Methods: The study focused on 1965 patients undergoing surgery for benign and malignant thyroid diseases at a tertiary-level academic center. Anamnestic, biochemical, surgical, pathological, and follow-up data were evaluated. HypoPTH was defined by a serum concentration of PTH < 10 pg/mL on the first or the second post-operative day. Persistent HypoPTH was defined by the need for calcium/active vitamin D treatment > 12 months after surgery. Results: Postoperative HypoPTH occurred in 542 patients. Multivariate analysis identified the association of central lymph-nodal dissection, reduced preoperative PTH levels, a lower rate of parathyroid glands preserved in situ, and longer duration of surgery as independent risk factors. At a median follow-up of 47 months, HypoPTH regressed in 443 patients (more than 6 months after surgery in 7%) and persisted in 53 patients. Patients receiving a lower dose of calcium/active vitamin D treatment at discharge (HR 0.559; p < 0.001) or undergoing prolonged, tailored, and direct follow-up by the operating endocrine surgeon team had a significantly lower risk of persistent HypoPTH (2.4% compared to 32.8% for other specialists) (HR 2.563; p < 0.001). Conclusions: Various patient, disease, and surgeon-related risk factors may predict postoperative HypoPTH. Lower postoperative calcium/active vitamin D treatment and prolonged, tailored follow-up directly performed by operating endocrine surgeons may significantly reduce the rate of persistent HypoPTH.