Risk factors for developing hungry bone syndrome after parathyroidectomy for secondary hyperparathyroidism

Background: Parathyroidectomy is recommended for patients with secondary hyperparathyroidism and has been proven to reduce all-cause mortality and cardiovascular mortality. Hungry bone syndrome is a common complication of parathyroidectomy. Therefore, identifying the preoperative risk factor for hungry bone syndrome is meaningful. In this study, we aimed to determine possible risk factors and their thresholds for hungry bone syndrome after parathyroidectomy for patients with secondary hyperparathyroidism. Methods Participants with secondary hyperparathyroidism who underwent parathyroidectomy were finally enrolled in this study. Hungry bone syndrome is defined as immediate postoperative hypocalcemia (calcium ≤ 2.1 mmol/L) and/or prolonged hypocalcemia (> 4 days) after parathyroidectomy. Clinical information and preoperative and postoperative laboratory data were collected. Results In all, 92 participants with secondary hyperparathyroidism who underwent parathyroidectomy were finally enrolled in this study. Among them, 61 patients (66.3%) experienced hungry bone syndrome after parathyroidectomy with a mean age of 44.3 years. Patients who experienced hungry bone syndrome had a higher preoperative parathyroid hormone value (263 (221, 329) vs . 139 (91, 187); P  = 0.000) and phosphate value (2.42 ± 0.23 vs. 2.08 ± 0.61; P  = 0.003) but a lower preoperative calcium level (2.41 ± 0.18 vs. 2.59 ± 0.20, P  = 0.000). Meanwhile, patients with hungry bone syndrome were younger (44.3 years vs 51.9 years, P  = 0.003). From the ROC curve, parathyroid hormone had the highest AUC = 0.868 (95% CI, 0.781–0.930) and sensitivity and specificity rates of 0.803 (0.682–0.894) and 0.903 (0.742–0.980), respectively, at a threshold of 215.9 pmol/L. Conclusions Secondary hyperparathyroidism patients with higher preoperative parathyroid hormone and phosphate levels and lower calcium levels were more likely to develop hungry bone syndrome.