Justified follow-up: a final intraoperative parathyroid hormone (ioPTH) Over 40 pg/mL is associated with an increased risk of persistence and recurrence in primary hyperparathyroidism.

Abstract

After parathyroidectomy for sporadic primary hyperparathyroidism (PHPT), overall rates of persistence/recurrence are extremely low. A marker of increased risk for persistence/recurrence is needed. We hypothesized that final intraoperative parathyroid hormone (FioPTH) ≥40pg/mL is indicative of increased risk for disease persistence/recurrence, and can be used to selectively determine the degree of follow-up. A retrospective review of PHPT patients undergoing parathyroidectomy with ioPTH monitoring was performed. An ioPTH decline of 50% was the only criteria for operation termination. Patients were grouped based on FioPTH of <40, 40-59, and >60pg/mL. Between 2001 and 2012, 1,371 patients were included. Mean age was 61±0.4years, and 78°% were female. Overall persistence rate was 1.4°%, with a 2.9°% recurrence rate. Overall, 976 (71°%) patients had FioPTH <40, 228 (16.6°%) had FioPTH 40-59, and 167 (12.2°%) had FioPTH ≥60. Mean follow-up was 21±0.6months. Patients with FioPTH <40 were younger, with lower preoperative serum calcium, PTH, and creatinine (all p≤0.001). Patients with FioPTH <40 had the lowest persistence rate (0.2%) versus patients with FioPTH 40-59 (3.5%) or FioPTH ≥60 (5.4%; p<0.001). Recurrence rate was also lowest in patients with FioPTH <40 (1.3 vs. 5.9 vs. 8.2%, respectively; p<0.001). Disease-free status was greatest in patients with FioPTH <40 at 2years (98.5 vs. 96.8 vs. 90.5%, respectively) and 5years (95.7 vs. 72.3 vs. 74.8%, respectively; p<0.01). Patients with FioPTH <40pg/mL had lower rates of persistence and recurrence, than patients with FioPTH 40-59, or ≥60. Differences became more apparent after 2years of follow-up. Patients with FioPTH ≥40pg/mL warrant close and prolonged follow-up.