A Novel Risk Score to Predict Hungry Bone Syndrome After Parathyroidectomy for Renal Hyperparathyroidism

Objective: Hungry bone syndrome (HBS) is a known complication of parathyroidectomy. Patients with renal hyperparathyroidism are particularly vulnerable to HBS because of their prolonged exposure to electrolyte abnormalities and elevated parathyroid hormone (PTH). However, in-depth characterization of predictive factors for HBS in these patients is lacking.

Methods: A retrospective analysis was performed of patients with renal hyperparathyroidism who underwent parathyroidectomy at a single institution from 2011-2021. Patient demographics, clinical characteristics, and biochemical data were collected and analyzed. Boruta and binary logistic regression analyses were used to develop a scoring system.

Results: Thirty-three patients were identified; 16 (48%) developed HBS. Patients with HBS had significantly higher preoperative levels of serum PTH (mean difference [MS] = 2167.2 pg/mL, P <.001), phosphorus (MD = 3.5 mg/dl, P <.001), and alkaline phosphatase (ALP) (MD = 344.2 U/L, P =.002) and significantly lower levels of preoperative serum calcium (MD = -0.96 mg/dL, P =.004). Stepwise regression analysis identified elevated ALP (>150 U/L) and markedly elevated PTH (>1000 pg/mL) as positive predictors of HBS. A two-point scoring system with these 2 variables had overall diagnostic accuracy of 96.8% (sensitivity 100% and specificity 94.1%) with 1 point conferring 93.8% positive predictive value and 2 points conferring 100% positive predictive value.

Conclusion: Preoperative serum PTH and ALP are significantly associated with HBS in patients with renal hyperparathyroidism undergoing parathyroidectomy for renal hyperparathyroidism. A scoring system with these 2 variables may be of clinical utility in predicting patients at high risk of HBS.