PTH Gradient as a Predictor of Post Thyroidectomy Hypocalcemia.

Area of Science:

• Endocrinology
• Surgical Complications
• Biochemistry

Background:

• Post-thyroidectomy hypocalcemia is a frequent complication.
• Current methods using single post-thyroidectomy parathyroid hormone (PTH) levels may inaccurately predict hypocalcemia.
• This study investigates the utility of the PTH gradient in predicting hypocalcemia.

Purpose of the Study:

• To evaluate the percentage change in preoperative and postoperative PTH (PTH gradient) as a predictor of post-thyroidectomy hypocalcemia.
• To determine the optimal PTH gradient cutoffs for predicting mild, severe, and clinical hypocalcemia.

Main Methods:

• Forty-one thyroidectomy patients had PTH measured preoperatively, at 1-hour postoperatively (PTH0), and at 1-day postoperatively (PTH1).
• PTH gradient (PTHG0, PTHG1) was calculated as the percentage change from preoperative to postoperative PTH levels.
• Hypocalcemia was classified as mild or severe based on corrected calcium levels and clinical presentation.

Main Results:

• Twenty-four-hour (24.3%) and 26.8% (11) of patients experienced mild and severe hypocalcemia, respectively.
• Both PTH0 and PTH1 gradients were significantly associated with hypocalcemia risk (P=0.006 and P=0.002).
• The PTH0 gradient demonstrated the highest predictive accuracy for hypocalcemia (AUC 0.855), while the PTH1 gradient was better for severe/clinical hypocalcemia (AUC 0.844).

Conclusions:

• The PTH gradient is a more reliable predictor of post-thyroidectomy hypocalcemia than single PTH measurements.
• A PTH0 gradient cutoff of 60% predicts hypocalcemia, and a PTH1 gradient >75% indicates a high risk of severe/clinical hypocalcemia.