SAT-745 Characterization of Permanent Post-surgical Hypoparathyroidism: Incidence, Morbidity, and Predictors of Remission in a Retrospective Cohort From a Hospital in Costa Rica

Abstract Disclosure: J.E. Esquivel Vargas: None. A.B. Santos Rojo: None. A. Hong Lo: None. A.L. Piedra Pacheco: None. L.F. Moya Porras: None. F. Ruiz Salazar: None. Introduction: Hypoparathyroidism is the most common complication of thyroidectomy, characterized by inadequate production of parathyroid hormone (PTH) to maintain normal serum calcium levels. Various risk factors have been identified, but predictors of remission remain poorly established. This condition involves significant morbidity, and its treatment should focus on preventing complications and normalizing biochemical control. This study represents the first characterization of patients with post-surgical hypoparathyroidism in Costa Rica. Methodology: An observational, retrospective, descriptive study based on medical records was conducted. Clinical, biochemical, morbidity, treatment parameters, and predictors of remission were analyzed in patients with permanent post-surgical hypoparathyroidism treated at Hospital México (San José, Costa Rica) between 2018 and 2023. Results: A sample of 110 patients with permanent post-surgical hypoparathyroidism was obtained from a total of 502 thyroidectomies performed during the specified period, with an incidence rate of 22%. Women accounted for 84% of the sample, with a median age of 51 years. Preoperative thyroid cancer diagnosis was present in 75% of the cases, where total thyroidectomy was the most frequently performed procedure. Initial biochemical values showed mean serum calcium levels of 7.49 mg/dL (normal range 8.5–10.5 mg/dL), phosphate 4.97 mg/dL (normal range 2.5–4.5 mg/dL), PTH 6.68 pg/mL (normal range 15–65 pg/mL), 25-OH vitamin D 29.1 ng/mL (normal range 30–100 ng/mL), and urinary calcium excretion 185.5 mg/24h (normal range 100–300 mg/24h). An improvement in biochemical control was observed when comparing final values. A remission state was achieved in 28.2% of the patients, with a median recovery time of 2.45 years. Predictors of remission included initial serum calcium levels (p=0.000), PTH (p=0.016), and initial serum phosphate levels (p=0.013). Additionally, initial serum phosphate levels were identified as a predictor of morbidity (p=0.0271) associated with elevated calcium-phosphate product levels. Conclusions: Permanent post-surgical hypoparathyroidism is a common complication in our setting, significantly impacting quality of life and associated morbidity. This study highlights the importance of early detection and proactive management of hypoparathyroidism to reduce morbidity and promote remission of this condition in this region. Presentation: Saturday, July 12, 2025