Hungry bone syndrome after parathyroidectomy in end-stage renal disease patients: review of an alkaline phosphatase-based treatment protocol

A nomogram prediction model for hungry bone syndrome in dialysis patients with secondary hyperparathyroidism after total parathyroidectomy

OBJECTIVE

Secondary hyperparathyroidism (SHPT) is a common complication of chronic kidney disease (CKD). Hungry bone syndrome (HBS) after parathyroidectomy (PTX) is a serious complication, which can lead to diarrhea, convulsion, arrhythmia and even death. This study was aimed to determine the risk factors for HBS after PTX in dialysis patients with SHPT and construct a nomogram prediction model to predict the incidence of postoperative complications.

METHODS

Clinical data were collected from 80 maintenance hemodialysis (MHD) patients with SHPT who received total PTX in the Second Hospital of Jilin University from January 2018 to September 2021. In line with the inclusion and exclusion criteria, totally 75 patients were finally enrolled for analysis. Patients were divided into two groups for retrospective analysis according to the severity of postoperative HBS, including HBS group and non-HBS (N-HBS) group. Univariate and multivariate logistic regression analyses were conducted to determine the risk factors for postoperative HBS. Afterwards, the receiver operating characteristic (ROC) curves were plotted based on the statistical analysis results, aiming to compare the prediction effects of different predicting factors. Finally, the nomogram was established to evaluate the occurrence probability of postoperative complications predicted by the risk factors.

RESULTS

Among the 75 patients, 32 had HBS (HBS group), while 43 did not have HBS (N-HBS group). Univariate analysis results indicated that, the preoperative intact parathyroid hormone (iPTH) and serum alkaline phosphatase (ALP) levels in HBS group were significantly higher than those in N-HBS group, while preoperative hemoglobin and preoperative albumin (Alb) levels were significantly lower than those in N-HBS group. As discovered by multivariate logistic regression analysis, preoperative iPTH (OR = 1.111, P = 0.029) and ALP (OR = 1.010, P < 0.001) were the independent risk factors for postoperative HBS. ROC curve analysis suggested that the area under the curve (AUC) values of these two indicators were 0.873 and 0.926, respectively (P < 0.0001). Subsequently, the nomogram model for predicting HBS was constructed. The model verification results indicated that the predicted values were basically consistent with the measured values, with the C-index of 0.943 (95% CI 0.892-0.994). Besides, the calibration curve was consistent with the ideal curve, demonstrating the favorable accuracy and discrimination of the model.

CONCLUSIONS

Preoperative iPTH and preoperative ALP are the risk factors for postoperative HBS, which can be used to guide the early clinical intervention.

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.

Forestalling Hungry Bone Syndrome after Parathyroidectomy in Patients with Primary and Renal Hyperparathyroidism

Hungry bone syndrome (HBS), severe hypocalcemia following parathyroidectomy (PTX) due to rapid drop of PTH (parathormone) after a previous long term elevated concentration in primary (PHPT) or renal hyperparathyroidism (RHPT), impairs the outcome of underlying parathyroid disease.

OBJECTIVE

overview HBS following PTx according to a dual perspective: pre- and post-operative outcome in PHPT and RHPT. This is a case- and study-based narrative review.

INCLUSION CRITERIA

key research words "hungry bone syndrome" and "parathyroidectomy"; PubMed access; in extenso articles; publication timeline from Inception to April 2023.

EXCLUSION CRITERIA

non-PTx-related HBS; hypoparathyroidism following PTx. We identified 120 original studies covering different levels of statistical evidence. We are not aware of a larger analysis on published cases concerning HBS (N = 14,349). PHPT: 14 studies (N = 1545 patients, maximum 425 participants per study), and 36 case reports (N = 37), a total of 1582 adults, aged between 20 and 72. Pediatric PHPT: 3 studies (N = 232, maximum of 182 participants per study), and 15 case reports (N = 19), a total of 251 patients, aged between 6 and 18. RHPT: 27 studies (N = 12,468 individuals, the largest cohort of 7171) and 25 case reports/series (N = 48), a total of 12,516 persons, aged between 23 and 74. HBS involves an early post-operatory (emergency) phase (EP) followed by a recovery phase (RP). EP is due to severe hypocalcemia with various clinical elements (<8.4 mg/dL) with non-low PTH (to be differentiated from hypoparathyroidism), starting with day 3 (1 to 7) with a 3-day duration (up to 30) requiring prompt intravenous calcium (Ca) intervention and vitamin D (VD) (mostly calcitriol) replacement. Hypophosphatemia and hypomagnesiemia may be found. RP: mildly/asymptomatic hypocalcemia controlled under oral Ca+VD for maximum 12 months (protracted HBS is up to 42 months). RHPT associates a higher risk of developing HBS as compared to PHPT. HBS prevalence varied from 15% to 25% up to 75-92% in RHPT, while in PHPT, mostly one out of five adults, respectively, one out of three children and teenagers might be affected (if any, depending on study). In PHPT, there were four clusters of HBS indicators. The first (mostly important) is represented by pre-operatory biochemistry and hormonal panel, especially, increased PTH and alkaline phosphatase (additional indicators were elevated blood urea nitrogen, and a high serum calcium). The second category is the clinical presentation: an older age for adults (yet, not all authors agree); particular skeleton involvement (level of case reports) such as brown tumors and osteitis fibrosa cystica; insufficient evidence for the patients with osteoporosis or those admitted for a parathyroid crisis. The third category involves parathyroid tumor features (increased weight and diameter; giant, atypical, carcinomas, some ectopic adenomas). The fourth category relates to the intra-operatory and early post-surgery management, meaning an associated thyroid surgery and, maybe, a prolonged PTx time (but this is still an open issue) increases the risk, as opposite to prompt recognition of HBS based on calcium (and PTH) assays and rapid intervention (specific interventional protocols are rather used in RHPT than in PHPT). Two important aspects are not clarified yet: the use of pre-operatory bisphosphonates and the role of 25-hydroxyitamin D assay as pointer of HBS. In RHPT, we mentioned three types of evidence. Firstly, risk factors for HBS with a solid level of statistical evidence: younger age at PTx, pre-operatory elevated bone alkaline phosphatase, and PTH, respectively, normal/low serum calcium. The second group includes active interventional (hospital-based) protocols that either reduce the rate or improve the severity of HBS, in addition to an adequate use of dialysis following PTx. The third category involves data with inconsistent evidence that might be the objective of future studies to a better understanding; for instance, longer pre-surgery dialysis duration, obesity, an elevated pre-operatory calcitonin, prior use of cinalcet, the co-presence of brown tumors, and osteitis fibrosa cystica as seen in PHPT. HBS remains a rare complication following PTx, yet extremely severe and with a certain level of predictability; thus, the importance of being adequately identified and managed. The pre-operatory spectrum of assessments is based on biochemistry and hormonal panel in addition to a specific (mostly severe) clinical presentation while the parathyroid tumor itself might provide useful insights as potential risk factors. Particularly in RHPT, prompt interventional protocols of electrolytes surveillance and replacement, despite not being yet a matter of a unified, HBS-specific guideline, prevent symptomatic hypocalcemia, reduce the hospitalization stay, and the re-admission rates.

Hungry bone syndrome after parathyroid surgery

INTRODUCTION

Data on the incidence rates of hungry bone syndrome after parathyroidectomy in patients on dialysis are inconsistent, as the published rates vary from 15.8% to 92.9%.

METHODS

Between 2009 and 2019, 120 hemodialysis patients underwent parathyroidectomy for secondary hyperparathyroidism at the Chang Gung Memorial Hospital. The patients were stratified into two groups based on the presence (n = 100) or absence (n = 20) of hungry bone syndrome after parathyroidectomy.

FINDINGS

Subtotal parathyroidectomy was the most common surgery performed (76.7%), followed by total parathyroidectomy with autoimplantation (23.3%). Pathological examination revealed parathyroid hyperplasia. Hungry bone syndrome developed within 0.3 ± 0.3 months and lasted for 11.1 ± 14.7 months. After surgery, compared with patients without hungry bone syndrome, patients with hungry bone syndrome had lower levels of nadir corrected calcium (P < 0.001), as well as lower nadir (P < 0.001) and peak (P < 0.001) intact parathyroid hormone levels. During 59.3 ± 44.0 months of follow-up, persistence and recurrence of hyperparathyroidism occurred in 25 (20.8%) and 30 (25.0%) patients, respectively. Furthermore, patients with hungry bone syndrome had a lower rate of persistent hyperparathyroidism than those without hungry bone syndrome (P < 0.001). Four patients (3.3%) underwent a second parathyroidectomy. Patients with hungry bone syndrome received fewer second parathyroidectomies than those without hungry bone syndrome (P < 0.001). Finally, a multivariate logistic regression model revealed that the preoperative blood ferritin level was a negative predictor of the development of hungry bone syndrome (P = 0.038).

DISCUSSION

Hungry bone syndrome is common (83.3%) after parathyroidectomy for secondary hyperparathyroidism in patients undergoing hemodialysis, and this complication should be monitored and managed appropriately.

A reappraisal of risk factors for early hypocalcemia after parathyroidectomy in dialysis patients

We aimed to identify risk factors for early hypocalcemia after parathyroidectomy in patients with secondary hyperparathyroidism. We retrospectively enrolled 106 of 120 consecutive patients with secondary hyperparathyroidism who underwent parathyroidectomy between January 2019 and July 2021. Perioperative laboratory parameters, preoperative computerized tomography (CT) images, and postoperative histology were evaluated. Parathyroid calcification was defined as hyperdense regions with a density of > 130 Hounsfield Units on CT images of the parathyroid. Subtotal parathyroidectomy, total parathyroidectomy without auto-transplantation, or total parathyroidectomy with auto-transplantation were performed in the present study. Postoperative hypocalcemia was defined as a serum calcium concentration < 2.1 mmol/L within 4 days of surgery. The participants were categorized according to the presence (n = 33) or absence (n = 73) of postoperative hypocalcemia. The demographics, comorbidities, and surgical details were similar in the two groups. Multivariate analysis showed that the preoperative alkaline phosphatase activity, serum intact parathyroid hormone and calcium concentrations, and parathyroid calcification were independent risk factors for postoperative hypocalcemia (all P < 0.05). Receiver operating characteristic analysis generated areas under the curves for preoperative alkaline phosphatase, intact parathyroid hormone, and parathyroid calcification of 0.82, 0.80, and 0.70, respectively (all P < 0.05). Cut-off values for preoperative alkaline phosphatase (> 242.9 IU/L) and intact parathyroid hormone (> 2,104 pg/mL) were found to be predictive of postoperative hypocalcemia. High preoperative alkaline phosphatase activity and serum intact parathyroid hormone concentration and low serum calcium are associated with higher risks of postoperative hypocalcemia. Calcification of the parathyroid may represent a novel radiologic means of predicting postoperative hypocalcemia.

Factors influencing the development of bone starvation syndrome after total parathyroidectomy in patients with renal hyperparathyroidism

Purpose

To investigate the factors affecting the development of bone starvation syndrome (HBS) after total parathyroidectomy in patients with renal hyperparathyroidism (SHPT).

Patients and methods

The clinical data and perioperative indices of 141 patients who underwent PTX for SHPT were retrospectively analyzed. The patients were divided into HBS and non-HBS groups based on postoperative minimum blood calcium <1.87 mmol/L. The differences in general clinical data and perioperative related indices between the two groups were compared; logistic regression analysis was performed to analyze the risk factors influencing HBS occurrence after surgery. Multiple linear regression method was used to analyze the factors influencing the maintenance time of intravenous calcium supplementation and total amount of calcium supplementation during intravenous calcium supplementation. The threshold value for the diagnosis of HBS was analyzed using the ROC subjects' working curve.

Results

HBS occurred in 46 (32.6%) patients. Univariate analysis showed statistically significant differences in dialysis age, preoperative calcitonin, preoperative parathyroid hormone, preoperative blood phosphorus, and preoperative alkaline phosphatase between both groups (P < 0.05). Logistic regression analysis using stepwise entry method concluded that preoperative alkaline phosphatase was an independent factor for the development of HBS after surgery. Preoperative parathyroid hormone was an independent factor for the duration of intravenous calcium supplementation and total calcium supplementation during intravenous calcium supplementation in the HBS group. Based on the ROC curve, for postoperative HBS, the cut-off ALP value was 199.5 U/L, with a sensitivity of 80.85% and specificity of 82.61%.

Conclusion

Preoperative serum ALP may be an independent factor for HBS occurrence after surgery. When preoperative ALP > 199.5 U/L, patients with SHPT are prone to HBS after surgery, and the higher the preoperative ALP, the higher the incidence of HBS, and vice versa. In addition, preoperative PTH may be the factor in the timing of postoperative intravenous calcium supplementation and the total amount of calcium supplementation during intravenous calcium supplementation in patients with HBS.

Advances in the treatment of secondary and tertiary hyperparathyroidism

Secondary hyperparathyroidism (SHPT) and tertiary hyperparathyroidism (THPT) are common and complicated clinical endocrine diseases. The parathyroid glands maintain endocrine homeostasis by secreting parathyroid hormone to regulate blood calcium levels. However, structural alterations to multiple organs and systems occur throughout the body due to hyperactivity disorder in SHPT and THPT. This not only decreases the patients' quality of life, but also affects mortality. Since current treatments for these diseases remains unclear, we aimed to develop a comprehensive review of advances in the treatment of SHPT and THPT according to the latest relevant researches.

Data to inform counseling on parathyroidectomy for secondary hyperparathyroidism of renal origin

BACKGROUND

The risk of postoperative hungry bone syndrome after parathyroidectomy for secondary hyperparathyroidism of renal origin may alter the course of treatment, including the hospital length of stay and readmission rates. We sought to identify additional patient or hospital factors that might contribute to hungry bone syndrome after parathyroidectomy in patients with secondary hyperparathyroidism of renal origin.

METHODS

Patients who underwent a parathyroidectomy for secondary hyperparathyroidism of renal origin were identified in a geographically diverse, 10-state, discharge data set. Covariates included demographic data, payer status, 31 comorbidities, and hospital characteristics. The primary outcome variable of interest was hospital length of stay. Secondary outcomes were complications and 30-day readmission.

RESULTS

Of 796 patients studied, 164 patients (20.6%) were diagnosed with hungry bone syndrome. There were no differences in the rates of hungry bone syndrome by race or number of comorbidities. The average age of hungry bone syndrome patients (45.7 years ± 13.9) was younger than that of non-hungry bone syndrome patients (50.7 ± 14.8; P < .001). Hungry bone syndrome was more common among obese patients than nonobese patients (25.0% vs 15.8%; P < .001). Parathyroid autotransplant was performed at similar rates in hungry bone syndrome and non-hungry bone syndrome patients (23.8% vs 23.1%; P = .821). Median length of stay was significantly longer for hungry bone syndrome patients (6 days, interquartile range: [4, 8] versus 3 days, interquartile range: [2-6]; P < .001). Similar 30-day readmission rates were observed (hungry bone syndrome: 41 (25%) versus non-hungry bone syndrome: 147 (23%); P = .640).

CONCLUSION

Hungry bone syndrome occurs in 1 of 5 patients after parathyroidectomy for secondary hyperparathyroidism of renal origin. Patients should be informed of the possibility of a relatively long (6 days) length of stay after surgery as well as the moderate possibility (>20%) of another hospitalization within the 30-day postdischarge period.

Clinical factors associated with early and persistent hypocalcaemia after parathyroidectomy in patients on dialysis with severe hyperparathyroidism

AIM

Severe hypocalcaemia following parathyroidectomy for secondary or tertiary hyperparathyroidism (SHPT/THPT) is scarcely studied. We aimed to describe and identify risk factors for early and persistent hypocalcaemia after parathyroidectomy.

METHODS

Retrospective pair-matched cohort study. We assessed 87 dialysis patients with SHPT (n = 73) or THPT (n = 14) paired with 146 subjects with primary hyperparathyroidism (PHPT) who underwent parathyroidectomy and were followed for 12 months. Early severe hypocalcaemia was defined as a free Ca ≤0.8 mmol/L [3.2 mg/dl] or corrected Ca ≤1.87 mmol/L [7.5 mg/dl] within 48 h. After parathyroidectomy and persistent hypocalcaemia, as an elemental Ca intake >3.0 g/day to achieve corrected Ca >2 mmol/L [8.0 mg/dl].

RESULTS

Early severe hypocalcaemia occurred in 77% (67/87) versus 6.8% (10/146) of subjects with SHPT/THPT and PHPT, respectively (p < .001). In SHPT/THPT cases, persistent hypocalcaemia occurred in 77% (49/64) and 64% (35/54) after 6 and 12 months of parathyroidectomy, respectively. In PHPT cases, persistent hypocalcaemia occurred in 6.8% (10/146) after 4-12 months of parathyroidectomy. Preoperative serum alkaline phosphatase (ALP) was the only risk factor associated to early severe hypocalcaemia (OR 7.3, 95% C.I. 1.7-10.9, p = .006) and persistent hypocalcaemia (OR 7.1, 95% C.I: 2.1-14.2, p = .011). Subjects with persistently low intact parathormone (iPTH) (<5.3 pmol/L [50 ng/ml]), suggestive of adynamic bone disease) showed higher Ca increases and less oral calcium requirements compared to those who progressively increased iPTH after parathyroidectomy.

CONCLUSION

Early and persistent hypocalcaemia after parathyroidectomy in severe HPT were a common event associated directly to preoperative ALP levels. Subjects with persistently low postoperative iPTH normalized serum Ca more frequently after 1 year of follow up.

Intensive calcium monitoring improves outcomes on hungry bone syndrome in hyperparathyroidism

Objectives. Hungry bone syndrome (HBS) is a severe and underdiagnosed complication of parathyroidectomy in the treatment of primary hyperparathyroidism (PHP) and secondary hyper-parathyroidism to chronic kidney disease (SHP-CKD).Methods. A longitudinal study was conducted to compare the postoperative outcomes of patients who developed HBS in two different time frames: before and after implementing a protocol with an intensive electrolytic monitoring and an algorithm regarding electrolytic supplementation.Results. Overall, 77 parathyroidectomies were included. In PHP, a protocol implementation led to an increased admission of patients in the Intermediate Care Unit for intensive electrolytic monitoring (p<0.001) and an increased rate of oral calcium replacement during hospital stay (p=0.013) compared to pre-protocol era. In SHP-CKD, duration of intravenous calcium replacement was reduced (p=0.010). The prevalence of HBS (9.8% in PHP and 58.3% in SHP-CKD) was similar between the two periods, although its diagnosis had an increased trend in PHP since the protocol implementation. None of the diagnosis of HBS was established due to hypocalcemic symptoms in the post-protocol era (contrary to pre-protocol period, p=0.021). Both hypocalcemia length and duration of surgical ward hospitalization were reduced (p=0.047 and p=0.042, respectively).Conclusions. An improved assessment of hyperparathyroidism and a decrease in HBS severity were noted in the post-protocol era. We strongly recommend the implementation of a standardized protocol with an intensive phosphocalcium monitoring in the high-risk patients who undergo parathyroidectomy due to hyperparathyroidism as it improves the health care and management of HBS.

Risk Factors for Severe Hypocalcemia in Patients with Secondary Hyperparathyroidism after Total Parathyroidectomy

BACKGROUND

Hypocalcemia is the most common complication of total parathyroidectomy in secondary hyperparathyroidism (SHPT) and is associated with adverse consequences such as spasms, epilepsy, and arrhythmia and even death if the serum calcium level decreases rapidly. Previous studies have identified several risk factors for postoperative severe hypocalcemia (SH) in patients with SHPT, but the sample sizes were small and thus the results may not be reliable.

OBJECTIVES

This study was performed to investigate the risk factors for SH after total parathyroidectomy without autotransplantation (tPTX) in a large sample of patients with uremic hyperparathyroidism.

METHODS

We retrospectively investigated the records of 1,095 patients with SHPT treated with tPTX between January 2008 and December 2018. Based on the postoperative serum calcium concentration, the patients were grouped into SH and non-SH groups. The clinical characteristics and biochemical results were analyzed, and binary logistic regression analysis was used to identify the risk factors for SH.

RESULTS

After surgery, 25.9% of the patients developed SH. Age, diastolic blood pressure (DBP), heart rate, frequency of bone pain, weight of resected glands, preoperative serum calcium, intact parathyroid hormone (iPTH), alkaline phosphatase (ALP), and hemoglobin levels differed between the two groups. Binary logistic regression analyses identified preoperative serum calcium, iPTH, and ALP levels as independent predictors of SH after surgery.

CONCLUSIONS

The preoperative serum calcium, iPTH, and ALP levels can be used to assess the risk of postoperative SH in patients with SHPT. Such patients should thus be monitored closely in order to initiate prompt interventions to avoid SH.