Risk factors for hypocalcemia after parathyroidectomy in maintenance hemodialysis patients with secondary hyperparathyroidism / 中华肾脏病杂志

ABSTRACT

Objective:To explore the risk factors of hypocalcemia and the correlation between calcium supplementation and clinical parameters after parathyroidectomy (PTX) in maintenance hemodialysis patients with secondary hyperparathyroidism (SHPT), and to analyze the effect of calcium supplementation after PTX on the long-term prognosis of patients.Methods:This study was a single-center retrospective study. The patients who underwent PTX in maintenance hemodialysis patients with SHPT in the Huashan Hospital affiliated to Fudan University from October 2014 to March 2021 were retrospectively enrolled. Total PTX with auto transplantation or total PTX alone were the surgical procedures. According to the postoperative requirement of calcium in the first week, the patients were divided into two groups: high calcium supplement (>16.05 g/week) group and low calcium supplement group (≤16.05 g/week). According to the average serum calcium level in the first week after operation, the patients were divided into hypocalcemia group (≤2.1 mmol/L) and non-hypocalcemia group (>2.1 mmol/L) and the differences of clinical parameters between the two groups were compared. The correlation between clinical parameters and the postoperative calcium requirement was examined through Pearson or Spearman correlation analysis. The influencing factors for hypocalcemia after PTX were examined through logistic regression analysis. The survival curve was made by Kaplan-Meier method, and the difference of cumulative survival rate between the two groups was compared by log-rank test.Results:A total of 98 maintenance hemodialysis patients with SHPT were enrolled. The levels of serum calcium, phosphorus, and intact parathyroid hormone (iPTH) after the operation decreased significantly than those of preoperation (all P<0.05). Multiple linear regression analysis showed age ( β=-0.160, P=0.030), iPTH ( β=0.004, P=0.025) and C-reactive protein ( β=0.186, P=0.011) were correlated with postoperative calcium requirement. Preoperative alkaline phosphatase ( OR=1.002, 95% CI 1.000-1.004, P=0.018) and hemoglobin ( OR=0.977, 95% CI 0.954-1.000, P=0.048) independently predicted the occurrence risk of postoperative hypocalcemia through multivariate logistic regression analysis. The recurrence rate of high calcium supplement group was higher than that of low calcium supplement group (10.26% vs 0, P=0.023) and there was no significant difference in all-cause mortality between the two groups (17.95% vs 5.08%, P=0.086). The recurrence rate between the hypocalcemia group and non-hypocalcemia group was no significantly different (8.3% vs 1.8%, P=0.451) and there was no significant difference in all cause mortality between the two groups (12.5% vs 12.7%, P=1.000). Kaplan-Meier survival curve showed that the cumulative survival rate between the two groups was no significantly different (log-rank test χ2=0.147, P=0.702). Conclusions:PTX is a safe and effective therapeutic method to reduce the level of iPTH and improve the metabolism of calcium and phosphorus in SHPT patients. Age, iPTH and C-reactive protein are correlated with the postoperative requirement of calcium in the first week. Preoperative alkaline phosphatase and hemoglobin are independent risk factors for postoperative hypocalcemia. Correcting preoperative electrolyte disorder, improving infection and anemia can reduce the incidence of hypocalcemia after PTX.