Risk factors of recurrent secondary hyperparathyroidism after adequate primary surgical treatment

BACKGROUND: Secondary hyperparathyroidism (SHPT) is a common condition in patients with end-stage renal disease (ESRD) who are on dialysis. Parathyroidectomy is a treatment for patients when medical therapy has failed. Recurrence may occur and is indicated for further surgery in the era of improved quality of care for ESRD patients. METHODS: We identified, 1060 patients undergoing parathyroidectomy from January, 2011 to June, 2020. After excluding patients without regular check-up at our institute, primary hyperparathyroidism, or malignancy, 504 patients were enrolled. Sixty-two patients (12.3%, 62/504) were then excluded due to persistent SHPT even after the first parathyroidectomy. We aimed to identify risk factors for recurrent SHPT after the first surgery. RESULTS: During the study period, 20% of patients who underwent parathyroidectomy at our institute (in, 2019) was due to recurrence after a previous parathyroidectomy. There were 442 patients eligible for analysis of recurrence after excluding patients with the persistent disease (n = 62). While 44 patients (9.95%) had recurrence, 398 patients did not. Significant risk factors for recurrent SHPT within 5 years after the first parathyroidectomy, including dialysis start time to first operation time < 3 years (p = 0.046), postoperative PTH >106.5 pg/mL (p < 0.001), and postoperative phosphorus> 5.9 mg/dL (p = 0.016), were identified by multivariate analysis. CONCLUSIONS: The starting time of dialysis to first operation time < 3 years in the patients with dialysis, postoperative PTH> 106.5 pg/mL, and postoperative phosphorus> 5.9 mg/dL tended to have a higher risk for recurrent SHPT within 5 years after primary treatment.