Long-term outcome of patients with elevated parathyroid hormone levels after successful parathyroidectomy for sporadic primary hyperparathyroidism.

HYPOTHESIS: Untreated long-term elevated parathyroid hormone (PTH) levels after successful parathyroidectomy may predict recurrent hyperparathyroidism (HPT). Although elevated PTH levels have been reported in eucalcemic patients after parathyroidectomy for sporadic primary HPT, the long-term clinical significance of this finding remains unclear.

DESIGN: Retrospective case series.

SETTING: Tertiary referral center.

PATIENTS: Five hundred seventy-six consecutive patients with HPT.

INTERVENTION: Parathyroidectomy guided by intraoperative monitoring of PTH levels.

MAIN OUTCOME MEASURES: Overall incidence of elevated PTH levels (measurements of >or= 70 pg/mL at any time during follow-up) and recurrent HPT (hypercalcemia and elevated PTH levels more than 6 months after parathyroidectomy).

RESULTS: Of the 505 patients who underwent successful parathyroidectomy in this series and were followed up for more than 6 months, 337 (66.7%) consistently had PTH levels within the reference range, and 168 (33.3%) had elevated PTH levels. Of the 168 patients with elevated PTH levels, only 8 (4.8%) developed recurrent disease. The earliest recurrence occurred 2 years postoperatively. Factors associated with elevated PTH levels included advanced age, higher preoperative PTH levels, and mild postoperative renal insufficiency.

CONCLUSION: Although one-third of the patients had elevated PTH levels after successful parathyroidectomy, most of these patients with elevated PTH levels (95%) will achieve long-term eucalcemia.