Hungry Bone Syndrome Risk Factors ID'd in Total PTx Patients

The syndrome is more likely to develop in younger patients and those with higher preoperative ALP levels and lower preoperative calcium levels.
The syndrome is more likely to develop in younger patients and those with higher preoperative ALP levels and lower preoperative calcium levels.

Chinese researchers have identified possible risk factors for hungry bone syndrome following total parathyroidectomy without autotransplantation. 

In a study of 62 hemodialysis and peritoneal dialysis patients who underwent surgery at a regional hospital from 2004 to 2014, Ping-Nam Wong, MD, of Kwong Wah Hospital in Hong Kong, and colleagues reported that hungry bone syndrome (HBS) developed in 27.4% of patients. They defined HBS as prolonged postoperative hypocalcemia (corrected serum calcium level of 2.1 mmol/L or below) lasting for 4 or more days and occurring within a month of parathyroidectomy. 

Some previous studies defined HBS as a quick, postoperative drop in serum calcium. Although this frequently occurred in the current study, the investigators discovered that severe hypocalcemia could be delayed up to 2 weeks. As calcium fell, serum alkaline phosphatase (ALP) rose. Serum phosphate also fell and then stabilized.

HBS patients received significantly more postoperative calcium and vitamin D supplementation. They also had longer hospital stays (15.4 vs 10.2 days).

“Patients should have their serum calcium, phosphate, and ALP levels closely monitored in the following 2 weeks, especially for those at risk,” Dr Wong and colleagues recommended in BMC Nephrology.

Multivariate analyses revealed that patients with the following attributes are at greater risk: younger age (47.5 vs 54.5 years for HBS vs no HBS, respectively), higher body weight (60.7 vs 49.8 kg), higher preoperative ALP level (415 vs 221 IU/L), and lower preoperative calcium level (2.44 vs 2.60 mmol/L).

Previous research has identified younger age and low preoperative calcium levels as HBS risk factors. ALP has been a controversial finding. Dr Wong and the team suggested that increased ALP reflects greater bone formation and signals a need for calcium replacement. The investigators reasoned that heavier patients with a higher bone mass would show a greater calcium deficit. No associations were found for preoperative parathyroid hormone levels or use of cinacalcet or paricalcitol, although those results might be shortcomings of the small sample size.

Due to the limitations of the study, such as its retrospective design, small and heterogenous population, and focus on a single institution, more data from multiple centers are needed to corroborate these results.

 

Reference

1. Ho LY, Wong PN, Sin HK, et al. Risk factors and clinical course of hungry bone syndrome after total parathyroidectomy in dialysis patientswith secondary hyperparathyroidism. BMC Neph. (2017) 18:12. doi: 10.1186/s12882-016-0421-5.

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