Predictors of permanent hypoparathyroidism following total thyroidectomy: a retrospective analysis

BACKGROUND:
Hypoparathyroidism (HPT) is a significant potential complication following thyroidectomy. Identifying predictors can aid in risk stratification, management, and potentially prevention.


OBJECTIVE:
To determine clinical and biochemical predictors of permanent HPT in post-thyroidectomy patients.


DESIGN:
Single-center, retrospective cohort study


SETTINGS:
Tertiary care center in Saudi Arabia


PATIENTS AND METHODS:
We conducted a retrospective analysis of 1085 patients who underwent total thyroidectomy from 2015 to 2022. Patients who developed postoperative HPT were categorized into transient and permanent HPT groups. Demographic, surgical, and biochemical variables were analyzed. Multivariable logistic regression was used to identify independent predictors of permanent HPT, using transient HPT as the reference.


MAIN OUTCOME MEASURES:
Identification of independent predictors associated with permanent HPT.


SAMPLE SIZE:
1085 patients, 264 with postoperative HPT


RESULTS:
We had 264 patients (24.3%) who developed postoperative HPT: 207 (19.1%) had transient and 57 (5.2%) had permanent HPT. Independent predictors of permanent HPT included thyroid cancer (Odds ratio, OR 2.08, 95% Confidence Interval, CI 1.03–4.17), autoimmune thyroid disease (OR 2.01, 95% CI 1.00–4.08), increased thyroid weight (OR 1.52 per 1 SD increase, 95% CI 1.08–2.14), and longer hospital stay (≥7 days) (OR 3.53, 95% CI 1.87–6.68). Preoperative vitamin D deficiency was identified as the only modifiable risk factor (OR 2.25, 95% CI 1.17–4.32). A postoperative parathyroid hormone (PTH) level ≤1.52 pmol/L within 24 hours was strongly associated with the risk of permanent HPT.


CONCLUSION:
Permanent HPT is significantly associated with preoperative vitamin D deficiency, thyroid malignancy, autoimmune thyroid disease, and greater thyroid weight. A postoperative PTH level ≤1.52 pmol/L is a reliable early biochemical predictor. Risk-based stratification may support individualized patient management and follow-up planning.


LIMITATIONS:
This was a single-center, retrospective study, limiting generalizability, in addition to the heterogeneity in surgeon experience and the time of PTH measurements post-operatively.