Abstract Background Post-Thyroidectomy Permanent Hypoparathyroidism (PTPH) is associated with multiple complications and increased mortality. Distinguishing patients at risk of PTPH from those with transient hypocalcaemia is essential for enforcing their life-long follow-up and optimal treatment. Methods we retrospectively analysed two prospective cohorts of total thyroidectomies performed in a single center between 2014-2020 (derivation, N= 2102) and 2021-2024 (validation, N= 536). Postoperative hypocalcaemia was defined by calcium level below 80 mg/L, or the presence of clinical symptoms. PTPH was defined as the need for calcium and/or vitamin D to maintain normocalcemia and/or prevent symptoms, in the presence of abnormal PTH levels, 6 months after surgery. Results the number of patients presenting postoperative hypocalcaemia and PTPH were respectively 288 (13,7%) and 35 (1,7%) (derivation cohort), and 60 (11,2%) and 7 (1,3%) (validation cohort). 14 variables associated with PTHP were selected in the derivation cohort. We then identified two models with optimal performances. First, a complete model, including 12 variables, which achieved the best overall discrimination (AUC). Second, a simple model, based on calcium and PTH at one month, which achieved the highest specificity while maintaining 100% sensitivity. Both models achieved similar performances in derivation and validation cohorts. Conclusion we developed and validated a simple model based on serum calcium and PTH levels at one month, allowing the early and accurate prediction of PTPH among patients with post-thyroidectomy hypocalcaemia. The simplicity and reproducibility of this model make it suitable for clinical use as an early postoperative risk stratification tool.
Demory et al. (Fri,) studied this question.