Hungry bone syndrome refers to profound hypocalcemia following parathyroidectomy in patients on dialysis. This can be avoided by prompt calcium replacement post operatively. We attempt to quantify the rate of Ca decline and identify predictors of high rate of decline post parathyroidectomy.

We analyzed  data for 267 patients who underwent parathyroidectomy from January 2012 to December 2016. Patients were divided into low (LCa) and high (HCa) Ca decline based on rate of Ca decline. The rate was defined as serum Ca pre-surgery minus serum Ca post-surgery divided by time of Ca test from stopping time of surgery in hours. (HCa >0.10mmol/L/Hr; LCa ≤ 0.10 mmol/L/hr). 

Univariate as well as multivariate analysis were performed.  Receiving operating characteristics analysis was performed to find cut-off points for diagnosis of clinically useful laboratory markers found significant in the multivariate analysis. 

76% of our patients are Chinese. 41.6% were male and 95.9% are on haemodialysis. Median age is 56 (50, 62) years-old and median dialysis vintage is 10 (6, 13) years. Median pre-surgery iPTH was 208.5pmol/L (154, 291), ALP 498U/L (303, 773), Pre-surgery Ca 2.53mmol/L(2.38, 2.68), and post-surgery Ca 2.26mmol/L(2.12, 2.43). 51.7% developed >10% decline in Ca post-surgery. 26.1% of patients develop HCa. Lower age, higher ALP and higher pre-surgery Ca were found in the HCa group leading to longer hospitalisation. On multivariate analysis, higher ALP and higher pre-surgery Ca were significantly associated with HCa.  AUC for ALP as a diagnostic test for HCa was 0.612 (0.540, 0.684). ALP ≥ 278 U/L for diagnostic of HCa will have sensitivity of 90% (80.5%, 95.9%), and specificity of 25.9% (19.9%, 32.6%)

Majority of our patient has >10% of decline in Ca post parathyroidectomy. Patients with ALP > 278U/L are at significant risk of high rate of Ca decline postsurgery and require longer hospitalisation.