Factors associated with late recurrence after parathyroidectomy for primary hyperparathyroidism

Background: A recent study with unusually lengthy follow-up after surgery for primary hyperparathyroidism reported higher recurrence rates than previously appreciated. We sought to identify specific factors associated with late recurrence after seemingly curative parathyroidectomy. Methods: Prospectively collected data were retrieved for patients who had surgical treatment of sporadic primary hyperparathyroidism with >= 3-year follow-up (3-17.6 years). Recurrence was defined by 6 months of eucalcemia with subsequent hypercalcemia and a high or unsuppressed parathyroid hormone. Recurrent patients were compared with cured patients (defined by consistent eucalcemia). Results: Among 261 patients, 28 (10.7%) had recurrence and 233 (89.3%) were cured. The mean time to recurrence was 77 months (range 13-170). The mean final intraoperative parathyroid hormone (49.0 pg/mL vs 37.5 pg/mL, P < .01), 6-month calcium levels (9.6 mg/dL vs 9.2 mg/dL, P = .02) and mean 6-month parathyroid hormone levels (86.5 pg/mL vs 59.6 pg/mL, P = .04) were higher for recurrence. By multivariable analysis, 6-month calcium >= 9.7 and eucalcemic elevation of the parathyroid hormone at 6 months were independently associated with recurrent primary hyperparathyroidism. Conclusion: Long-term follow-up after apparent curative surgery for primary hyperparathyroidism identified a high late recurrence rate (10.7%), up to 17 years later. A 6-month calcium >9.7 mg/dL and eucalcemic parathyroid hormone elevation at 6 months may be associated with recurrence, and such findings may help guide management. (C) 2019 Published by Elsevier Inc.