Persistent/Recurrent Primary Hyperparathyroidism: Does the Number of Abnormal Glands Play a Role?

BACKGROUND: Persistent/recurrent hyperparathyroidism occurs in 2%-5% of patients with sporadic primary hyperparathyroidism (PHPT). In this study, the incidence and time to recurrence in patients with single-gland disease (SGD), double adenomas (DAs), or four-gland hyperplasia (FGH) at initial parathyroidectomy were compared.

METHODS: This retrospective review included adult patients with sporadic PHPT who underwent initial parathyroidectomy with intraoperative parathyroid hormone monitoring (IOPTH) from 1/2000 to 12/2016 with ≥6 mo follow-up. An abnormal parathyroid was defined by a gland weight of ≥50 mg. A concurrent serum calcium >10.2 mg/dL and parathyroid hormone >40 pg/mL was defined as persistent PHPT if present <6 mo and recurrent PHPT if present ≥6 mo postoperatively after initial normocalcemia.

RESULTS: Of 1486 patients, 1203 (81%) had SGD, 159 (11%) DA, and 124 (8%) FGH. Among the 3 groups, there was no difference in the percent decrease from the baseline or time of excision to final postexcision IOPTH levels between groups (79% versus 80% versus 80%, respectively; P = 0.954) or in the proportion of patients with a final IOPTH ≥40 (22% versus 18% versus 14%; P = 0.059). Overall, 22 (1.5%) had persistent PHPT and 26 (1.7%) had recurrent PHPT. Persistent PHPT was more frequent with DAs (6; 3.8%) than other groups (SGD: 16, 1.3%; FGH: 0; P = 0.02). At median follow-up of 33 mo (IQR, 18-60), there was no difference in recurrence rate (1.6% versus 2.5% versus 2.4%; P = 0.57) or median time (mo) to recurrence (SGD: 59 [IQR, 21-86], DAs: 36 [IQR, 29-58], FGH: 23 [IQR, 17-40]; P = 0.46).

CONCLUSIONS: Recurrent PHPT occurred in 1.7% of patients who underwent curative initial parathyroidectomy, with no difference in incidence or time to recurrence between groups based on the number of glands removed. Patients with DA more commonly had persistent PHPT, raising the possibility of unrecognized FGH.