Factors Associated with Hypoparathyroidism and Vocal Cord Paralysis Following Thyroid Surgery: A Multicenter Cross-Sectional Analysis of 3,365 Cases

Postoperative hypocalcemia caused by hypoparathyroidism and vocal cord paralysis remain common complications following thyroid surgery. Sex and metabolic comorbidities may influence their occurrence. We conducted a multicenter cross-sectional analysis using anonymized data from 3,365 patients (1,517 hemithyroidectomies and 1,848 thyroidectomies) treated at 27 German hospitals between 2019 and 2024. Primary outcomes were postprocedural hypoparathyroidism and vocal cord paralysis, identified via ICD-10 codes. Associations with age, sex, obesity, diabetes, thyroid pathology, and surgical extent were analyzed using multivariable logistic regression. Postoperative hypoparathyroidism was more frequent after thyroidectomy (3.6%) than hemithyroidectomy (0.3%). Female sex was positively associated with postoperative hypoparathyroidism (odds ratio: 2.30; 95% confidence interval: 1.11-4.77), while obesity was inversely associated with postoperative hypoparathyroidism (odds ratio: 0.15; 95% confidence interval: 0.04-0.63). Vocal cord paralysis was observed in 1.7% of hemithyroidectomy and 1.0% of thyroidectomy cases. Factors significantly or tendentially associated with vocal cord paralysis included malignant neoplasm (odds ratio: 4.00; 95% confidence interval: 1.37-11.64), diffuse goiter (odds ratio: 4.94; 95 % confidence interval: 0.86-28.37), parathyroidectomy (odds ratio: 3.47; 95% confidence: 1.04-11.59), and diabetes mellitus (odds ratio: 3.09; 95% confidence: 0.98-9.74). Individual risk profiling and intraoperative neuromonitoring are critical to improving outcomes after thyroid surgery.