Prevalence and Predictors of Postoperative Hypoparathyroidism: A Multicenter Observational Study

Background/Objectives: Hypoparathyroidism (HPT) is a common complication following thyroid surgery with an incidence reaching up to 29%, potentially resulting in significant long-term morbidity. To improve its early identification and patient outcomes, we investigated the prevalence and predictors of postoperative HPT. Methods: This retrospective, multicenter observational study included patients who underwent thyroid surgery from 2016 to 2022 in four centers located in Saudi Arabia's Eastern Province. We analyzed demographic data, underlying thyroid or parathyroid conditions, surgical indications, types of procedures, pathology results, and preoperative corrected calcium and vitamin D levels, along with postoperative corrected calcium and parathyroid hormone (PTH) levels. For data analysis, IBM Statistical Package for the Social Sciences (SPSS) Statistics 22 was used, with categorical variables presented as frequencies/percentages and non-normal continuous variables as the median/first quartile (Q1) and third quartile (Q3). Associations were tested with chi-square/Fisher exact tests, medians with Mann-Whitney U-tests, and odds ratios (ORs) with 95% confidence intervals (CIs) via multivariate analysis with statistical significance set at p < 0.05. Results: A total of 679 cases were included. The median age of patients was 43 years (with 48.9% of them aged 41-60 years), and 82% were female. HPT occurred in 228 cases (35.3%), with 115 (81.0%) experiencing transient HPT and 27 (19.0%) permanent HPT. Multivariate analysis identified total thyroidectomy (OR 2.7, p = 0.005), completion thyroidectomy (OR 8.4, p = 0.004), and low immediate postoperative PTH level (OR 3.1, p < 0.001) as independent predictors of HPT. Central lymph node dissection (CLND; OR 4.03, p = 0.004) and low postoperative PTH level (OR 2.56, p = 0.049) were significant predictors of permanent HPT. Conclusions: Key predictors of HPT include surgical extent and low postoperative PTH level, while CLND and low postoperative PTH level are the strongest predictors of permanent HPT. Careful assessment of these risks when determining the extent of surgery and avoiding unnecessary aggressive procedures can help to minimize the occurrence of HPT. Measuring the PTH level immediately after surgery may aid in identifying high-risk patients for early intervention and appropriate follow-up.