Early Postoperative Intact Parathyroid Hormone Dynamics After Curative Parathyroidectomy for Sporadic Primary Hyperparathyroidism: Trajectories, Predictors of Eucalcemic PTH Elevation, and 18-Month Outcomes.

OBJECTIVE

Eucalcemic postoperative parathyroid hormone elevation (PePTH) after curative parathyroidectomy for sporadic primary hyperparathyroidism is common, yet its temporal profile and clinical significance remain unclear. Transient hypoparathyroidism also occurs after surgery, but the immediate course of intact PTH (iPTH) recovery is poorly defined. We therefore characterized day-by-day postoperative calcium, phosphate, and iPTH trajectories through postoperative day (POD) 5 and evaluated preoperative predictors of PePTH at 6 months and 18-month biochemical outcomes.

METHODS

In this prospective cohort study, 58 adults with sporadic primary hyperparathyroidism underwent curative minimally invasive parathyroidectomy with intraoperative PTH confirmation of cure and were followed for 18 months. Albumin-corrected calcium, phosphate, and iPTH were measured preoperatively; at 6 h; daily through POD5; and at 3, 6, 12, and 18 months. Three-variable model (iPTH, estimated glomerular filtration rate (eGFR), and beta-C-terminal telopeptide of type I collagen (β-CTX)) assessed via Firth logistic regression and AUROC.

RESULTS

IPTH reached a nadir at 6 h (median 12.1 pg/mL), re-entered the reference range by POD2, and stabilized by POD5, remaining similar at 3 months. Calcium normalized within 48 h, whereas phosphate rose from POD2 and stabilized by 3 months. PePTH occurred in 13/58 patients (22%). Higher baseline iPTH, lower eGFR, and higher β-CTX independently predicted PePTH (AUROC 0.81). During 18-month follow-up, biochemical recurrence occurred in 6/13 patients (46%) with PePTH and in 0/45 patients with normalized iPTH.

CONCLUSION

After curative parathyroidectomy, higher baseline iPTH, β-CTX, and lower eGFR identified patients at increased risk of PePTH at 6 months. PePTH was associated with biochemical recurrence through 18 months and may identify higher-risk postoperative phenotype requiring closer follow-up.