Intravenous Calcium Supplementation in Patients with Secondary Hyperparathyroidism after Total Parathyroidectomy: Serum Phosphorus as an Indicator

Background: Intravenous calcium supplementation (ICS) regimen after parathyroidectomy (PTX) mostly relies on immediate serum calcium level(SC-ICS) to adjust the dose and maintenance time of calcium supplementation, and there is a lack of standardized treatment regimen, with a wide range of individual variations, and the short-term/long-term efficacy and safety are still unclear. In this study, we propose a serum phosphorus level-guided ICS(SP-ICS) regimen to improve the efficiency and recurrence rate of hypocalcemia treatment after PTX. Methods: This study retrospectively analyzed the clinical data of 36 cases of SHPT patients with total parathyroidectomy (tPTX). According to ICS is divided into serum calcium-guided ICS regimen (SC-ICS) and serum phosphorus-guided ICS regimen (SP-ICS). Both groups of patients were allowed to have a free diet after the operation, and oral calcium and osteotriol supplementation were given. The occurrence of (Hungry Bone Syndrome) HBS and hypocalcemia after surgery was recorded in all patients. Results: A total of 36 cases were recruited in the respective cohort (18 cases in SC-ICS and 18 ones in SP-ICS). There was no significant difference in the baseline data between the two groups. Postoperative serum PTH and serum calcium levels were significantly decreased in both groups and hypocalcemia occurred in all patients. Compared with the SC-ICS group, the SP-ICS group had a longer postoperative hospitalization [9.5 (7.25,12.75) vs 5.0 (5.0,9.5), p=0.015] and a greater cumulative dose of 10% GN supplementation (540 ml±100 ml vs 190 ml±50 ml, p=0.039 ). At 6 month postoperative follow-up, one case died of hypocalcemia in the SC-ICS group, and the incidence of hypocalcemia was lower in the SP-ICS group than in the SC-ICS group (8.3% vs. 27.3%, p=0.022), and at one-year postoperative follow-up, the incidence of hypocalcemia was lower in the SP-ICS group than in the SC-ICS group (8.3% vs. 50%, p=0.024). Conclusion: Both SC-ICS and SP-ICS can effectively correct hypocalcemia after tPTX, and the dose and duration of calcium supplementation of SP-ICS regimen is higher than that of SC-ICS regimen, and SP-ICS regimen significantly reduces the incidence of long-term hypocalcemia and the risk of lethal hypocalcemia, and improves the quality of patient survival.