Persistently Elevated PTH After Parathyroidectomy at One Year: Experience in a Tertiary Referral Center

Context/Objective: Increased PTH after successful parathyroid surgery represents a clinical conundrum. We aimed to determine the prevalence of persistently elevated PTH (PePTH) postsurgery, along with predisposing factors. Design: and Setting: Patients >= age 18 with parathyroidectomy performed at University of North Carolina Hospitals for primary hyperparathyroidism (PHPT) over a 12-year period were identified from the Carolina Data Warehouse. Clinical and demographic characteristics were collected, transformed, and analyzed. Results: Five hundred seventy patients met initial criteria for PHPT, and of those 407 had postoperative values. One hundred forty-four had laboratory results within 3 to 18 months post operatively. There was no clinical difference between those with and without long-term laboratory follow-up. Presurgery, patients had average calcium of 11 mg/dL and PTH 125.4 pg/mL. Ninety-seven percent of patients had normalized calcium after surgery, but 30% had PePTH, which can be predicted at 3 months. Patients with PePTH (persistent elevation of PTH) after surgery did not differ from those with normalized PTH in terms of sex, age, body mass index, or excised gland weight; presurgery 25-vitamin D was slightly lower, but not abnormal (26 +/- 15 vs 36 +/- 11). The presurgical PTH was significantly higher (P< 0.001) in those with PePTH (156.5 pg/mL compared with presurgical level of 102.5 in those whose PTH normalized). Conclusions: Nearly one-third of PHPT patients have elevated PTH levels postsurgery in a tertiary hospital setting. At presentation, patients with PePTH tend to have higher PTH relative to calcium levels. Whether PePTH after surgical treatment of PHPT has pathological consequences is unknown.