Early intact PTH (iPTH) is an early predictor of postoperative hypocalcemia for a safer and earlier hospital discharge: an analysis on 260 total thyroidectomies

Davide Inversini, Stefano Rausei, Cesare Carlo Ferrari, Francesco Frattini, Angkoon Anuwong, Hoon Yub Kim, Xiaoli Liu, Chei-Wei Wu, Wen Tian, Renbin Liu, Gianlorenzo Dionigi


Background: Hypocalcemia is the most frequent complication after thyroidectomy. Serum calcium levels are reliable only 48–72 hours postoperatively. Early intact PTH (iPTH) has been proposed as early predictor of postoperative hypocalcemia. Our aim is to assess the ability of iPTH in predicting postoperative hypocalcemia.
Methods: Two hundred and sixty patients underwent thyroidectomy with postoperative iPTH evaluation. The iPTH samplings were early performed after thyroidectomy. The calcium levels were dosed postoperatively. Age, sex, clinical diagnosis, obesity, comorbidities, previous neck surgery, preoperative therapy, type of surgery, dissectors used, lymphadenectomy, post-operative complications, reoperation and histological diagnosis were considered. The primary end-point was the postoperative hospital stay. The secondary end-points were serum calcium and iPTH. Three iPTH cut-offs were tested to assess which was the best value (10.0, 15.0, and 20.0 pg/mL).
Results: The iPTH cut-off value of 10.0 pg/mL was the most accurate and specific for hypocalcemia. Comparing the iPTH value with the different values of calcium respectively 24 and 48 hours after surgery, a statistically stronger association with the serum calcium levels 48 hours postoperatively has been shown. iPTH ≥10 pg/mL 3–6 hours after surgery was strongly correlated to early discharge.
Conclusions: The correlation of iPTH with hypocalcemia is significant since a few hours after surgery and the value of iPTH ≥10 pg/mL is able to select those patients for a safe and early discharge. The use of the iPTH might avoid unnecessary extensions of hospitalization.