Predictors of early postoperative hypocalcemia in hemodialysis patients with secondary hyperparathyroidism

Predictive Risk Score for Postparathyroidectomy Hungry Bone Syndrome in Patients With Secondary Hyperparathyroidism

PURPOSE

Secondary hyperparathyroidism (SHPT) frequently affects patients with end-stage renal disease. Hungry bone syndrome (HBS) is a common complication among patients who undergo parathyroidectomy for SHPT and may cause prolonged hospitalization or require intensive care. The objective of this study is to develop a scoring system to stratify patients according to their risk of developing HBS.

METHODS

A retrospective cohort study was performed using the US Renal Data System (2010-2021). Univariable and multivariable logistic regression models were developed and weighted β-coefficients from the multivariable model were used to construct a risk score for the development of HBS. Positive and negative predictive values were assessed.

RESULTS

Of 17 074 patients who underwent parathyroidectomy for SHPT, 19.4% developed HBS. Intensive care unit admission was more common in patients who developed HBS (33.5% vs 24.6%, P < .001). On multivariable logistic regression analysis, younger age, renal osteodystrophy, longer duration of dialysis, longer duration of kidney transplant, and higher Elixhauser score were significantly associated with HBS. A risk score based on these clinical factors was developed, with a total of 6 possible points. Rates of HBS ranged from 8% in patients with 0 points to 44% in patients with 6 points. The risk score had a poor positive predictive value (20.3%) but excellent negative predictive value (89.3%) for HBS.

CONCLUSION

We developed a weighted risk score that effectively stratifies patients by risk for developing HBS after parathyroidectomy. This tool can be used to counsel patients and to identify patients who may not require postoperative hospitalization.

Dynamic nomogram for predicting hungry bone syndrome before parathyroidectomy

PURPOSE

The objective of this study was to develop a dependable and uncomplicated prediction model utilizing clinical information readily accessible to patients before surgery. This model aimed to assess the likelihood of hungry bone syndrome occurrence in post-surgery patients with secondary hyperparathyroidism (SHPT), and to assist clinicians in adjusting treatment plans promptly.

METHODS

In this study, we constructed an online nomogram utilizing independent variables determined through multiple logistic regression to predict the probability of HBS occurrence after parathyroidectomy in patients with secondary hyperparathyroidism. To evaluate the precision and dependability of the nomogram, we used receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA).

RESULTS

Multivariate logistic regression analyses on 136 eligible patients identified age, parathyroid hormone (PTH), and blood calcium as independent HBS risk factors, which were then integrated into the nomogram. The area under ROC curve demonstrated the nomogram's strong predictive accuracy. The calibration curve demonstrates consistency between the model's prediction probability and observed probability, reflecting high prediction accuracy of the nomogram. Dynamic nomograms were found to hold significant practical clinical value as demonstrated by clinical decision analysis. It can be accessed on https://min115.shinyapps.io/dynnomapp/ .

CONCLUSION

In patients with secondary hyperparathyroidism, the dynamic nomogram based on age, parathyroid hormone, and blood calcium can more accurately predict the likelihood of HBS after parathyroidectomy, allowing doctors to make clinical decisions more quickly and adjust treatment plans in a timely manner to reduce the incidence of HBS.

Pre-operative Cinacalcet Administration Reduces Immediate Post-operative Hypocalcemia Following Total Parathyroidectomy in Severe Renal Hyperparathyroidism

BACKGROUND

In severe renal hyperparathyroidism (RHPT), whether administrating Cinacalcet before total parathyroidectomy can reduce post-operative hypocalcemia remains unclear. We compared post-operative calcium kinetics between those who took Cinacalcet before surgery (Group I) and those who did not (Group II).

METHODS

Patients with severe RHPT (defined by PTH ≥ 100 pmol/L) who underwent total parathyroidectomy between 2012 and 2022 were analyzed. Standardized peri-operative protocol of calcium and vitamin D supplementation was followed. Blood tests were performed twice daily in the immediate post-operative period. Severe hypocalcemia was defined as serum albumin-adjusted calcium < 2.00 mmol/L.

RESULTS

Among 159 patients who underwent parathyroidectomy, 82 patients were eligible for analysis (Group I, n = 27; Group II, n = 55). Demographics and PTH levels before Cinacalcet administration were comparable (Group I: 169 ± 49 pmol/L vs Group II: 154 ± 45, p = 0.209). Group I had significantly lower pre-operative PTH (77 ± 60 pmol/L vs 154 ± 45, p < 0.001), higher post-operative calcium (p < 0.05), and lower rate of severe hypocalcemia (33.3% vs 60.0%, p = 0.023). Longer duration of Cinacalcet use correlated with higher post-operative calcium levels (p < 0.05). Cinacalcet use for > 1 year resulted in fewer severe post-operative hypocalcemia than non-users (p = 0.022, OR 0.242, 95% CI 0.068-0.859). Higher pre-operative ALP independently correlated with severe post-operative hypocalcemia (OR 3.01, 95% CI 1.17-7.77, p = 0.022).

CONCLUSION

In severe RHPT, Cinacalcet led to significant drop in pre-operative PTH, higher post-operative calcium levels, and less frequent severe hypocalcemia. Longer duration of Cinacalcet use correlated with higher post-operative calcium levels, and the use of Cinacalcet for > 1 year reduced severe post-operative hypocalcemia.

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.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Secondary and Tertiary Renal Hyperparathyroidism

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate treatment of secondary (SHPT) and tertiary (THPT) renal hyperparathyroidism.

BACKGROUND

Hyperparathyroidism is common among patients with chronic kidney disease, end-stage kidney disease, and kidney transplant. The surgical management of SHPT and THPT is nuanced and requires a multidisciplinary approach. There are currently no clinical practice guidelines that address the surgical treatment of SHPT and THPT.

METHODS

Medical literature was reviewed from January 1, 1985 to present January 1, 2021 by a panel of 10 experts in SHPT and THPT. Recommendations using the best available evidence was constructed. The American College of Physicians grading system was used to determine levels of evidence. Recommendations were discussed to consensus. The American Association of Endocrine Surgeons membership reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines present the epidemiology and pathophysiology of SHPT and THPT and provide recommendations for work-up and management of SHPT and THPT for all involved clinicians. It outlines the preoperative, intraoperative, and postoperative management of SHPT and THPT, as well as related definitions, operative techniques, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Preoperative and Perioperative Care, Surgical Planning and Parathyroidectomy, Adjuncts and Approaches, Outcomes, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal management of secondary and tertiary renal hyperparathyroidism.

A predictive risk score to diagnose hypocalcemia after parathyroidectomy in patients with secondary hyperparathyroidism: a 22-year retrospective cohort study

Hypocalcemia is a common complication found in patients with secondary hyperparathyroidism (SHPT) who undergo parathyroidectomy. This study aimed to construct a predictive risk score for the occurrence of hypocalcemia after parathyroidectomy in patients with SHPT who underwent chronic renal replacement therapy (RRT). This 22-year retrospective cohort study enrolled 179 patients with SHPT who had their first parathyroidectomy. Eighty-two percent of patients developed hypocalcemia within 16.9 (95% CI 14.5–19.5) h after parathyroidectomy. This study demonstrated four factors as independent risk factors for post-parathyroidectomy hypocalcemia, including duration of RRT, preoperative serum phosphate, preoperative serum alkaline phosphatase (ALP) and mean difference of serum intact parathyroid hormone (iPTH). By using logistic regression analysis, this study demonstrated cut-off points for these four risk factors for the diagnosis of hypocalcemia after parathyroidectomy: 5 years for the duration of RRT, 5 mg/dL for serum phosphate, 387 U/L for serum ALP, and 97% for the mean difference of serum iPTH. Finally, the predictive risk score was constructed by assigning a score of one to each factor. With a total score of at least 2, the proposed predictive risk score has an AuROC of 0.755 with a sensitivity of 78.2%, a specificity of 71.4%, and an accuracy of 76.9%.

Effect of calcium supplementation on severe hypocalcemia in patients with secondary hyperparathyroidism after total parathyroidectomy

BACKGROUND

Severe hypocalcemia (SH) is a dreaded complication of total parathyroidectomy (TPTX) without auto-transplantation.

AIM

To compare conventional and preventive calcium supplementation (CS) regimens in terms of SH occurrence after TPTX.

METHODS

This retrospective study included patients who underwent TPTX between January 2015 and May 2018 at the China-Japan Friendship Hospital. From January 2015 to May 2016, conventional CS was performed in patients who underwent TPTX, with calcium amounts adjusted according to postoperative serum calcium levels. From October 2016 to May 2018, preventive CS was performed according to preoperative alkaline phosphatase (ALP) levels. The patients were defined as low-risk (ALP < 500 U/L) and high-risk (ALP > 500 U/L) for SH. All preoperative blood samples were collected in the fasting state on the day before surgery. Postoperative blood samples were obtained at 6-7 AM from the first postoperative day.

RESULTS

A total of 271 patients were included. These patients were 47.7 ± 11.1 years old, and 57.6% were male. Their mean body mass index (BMI) was 22.9 ± 3.8 kg/m². There were no significant differences in sex, age, BMI, preoperative ALP, serum calcium, serum phosphorus, calcium-phosphorus ratio, and intact parathyroid hormone (iPTH) between the two CS groups. Compared with conventional CS, preventive CS led to lower occurrence rates of hypocalcemia within 48 h (46.0% vs 74.5%, P < 0.001) and SH (31.7% vs 64.1%, P < 0.001). Multivariable analysis showed that preoperative iPTH levels [odds ratio (OR) = 1.001, 95% confidence interval (CI): 1.000-1.001, P = 0.009), preoperative ALP amounts (OR = 1.002, 95%CI: 1.001-1.003, P = 0.002), preoperative serum phosphorus levels (OR = 8.729, 95%CI: 1.518-50.216, P = 0.015) and preventive CS (OR = 0.132, 95%CI: 0.067-0.261, P < 0.001) were independently associated with SH. In patients with preoperative ALP ≥ 500 U/L, only preventive CS (OR = 0.147, 95%CI: 0.038-0.562. P = 0.005) was independently associated with SH.

CONCLUSION

This study suggests that preventive CS could reduce the occurrence of SH, indicating its critical value for hypocalcemia after TPTX.

Construction and validation of a predictive model for hypocalcemia after parathyroidectomy in patients with secondary hyperparathyroidism

OBJECTIVE

We aimed to construct and validate a predictive model for the risk of hypocalcemia following parathyroidectomy (PTX) for the treatment of secondary(renal) hyperparathyroidism (SHPT).

METHODS

Information regarding patients with SHPT who underwent PTX between January 2019 and April 2022 was collected retrospectively. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for hypocalcemia following PTX and to construct predictive models. The areas under the receiver operating characteristic curve (AUC), the calibration curve, and the clinical decision curve (decision curve analysis, DCA) were used to assess the discrimination, calibration, and level of clinical benefit obtained using the predictive models.

RESULTS

We studied 238 patients who were randomly allocated in a 7:3 ratio to a training group (n=166) and a test group (n=72). Univariate and multivariate logistic regression analyses were performed, in which three variables (the circulating parathyroid hormone (PTH) and Ca concentrations, and alkaline phosphatase (ALP) activity) were interrogated for possible roles as independent risk factors for hypocalcemia in patients with SHPT who undergo PTX, and used to construct predictive models. The AUCs for the constructed models were high for both the training (0.903) and test (0.948) groups. The calibration curve showed good agreement between the incidence of postoperative hypocalcemia estimated using the predictive model and the actual incidence. The DCA curve indicated that the predictive model performed well.

CONCLUSION

A predictive model constructed using a combination of preoperative PTH, Ca, and ALP may represent a useful means of identifying patients with SHPT at high risk of developing hypocalcemia following PTX in clinical practice.

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.

Incidence of and risk factors for post-parathyroidectomy hungry bone syndrome in patients with secondary hyperparathyroidism

Background

Hungry bone syndrome (HBS) following parathyroidectomy is associated with severe hypocalcemia and increased morbidity. This study aims to determine the incidence and risk factors of post-parathyroidectomy HBS in dialysis patients with secondary hyperparathyroidism (SHPT).

Methods

A retrospective cohort study was conducted, and medical records of patients with SHPT requiring parathyroidectomy between January 2014 and January 2020 were reviewed. HBS was defined as the requirement of intravenous calcium administration due to hypocalcemia-related symptoms and/or reductions in serum calcium concentration (<8.4 mg/dL) within 72 h after parathyroidectomy.

Results

A total of 130 dialysis patients were enrolled. The majority of patients (85.4%) received hemodialysis and the remaining patients (14.6%) received peritoneal dialysis. Ectopic parathyroid glands were identified in 6.6% of patients by preoperative parathyroid scintigraphy. Diffuse parathyroid hyperplasia was the most common histopathological characteristic of SHPT (90.8%). HBS occurred in 82.3% of patients following parathyroidectomy. Preoperative serum intact parathyroid hormone (iPTH) concentration was significantly correlated with serum calcium (r = −0.48, p < 0.01) and alkaline phosphatase (ALP) concentration (r = 0.71, p < 0.01). Patients with HBS had significantly longer hospital stays than patients without (8 versus 3 days, p < 0.01). Based on multiple logistic regression analysis, young age (≤45 years), high preoperative serum ALP (>420 IU/L) and iPTH (>1,000 pg/mL), and absence of preoperative hypercalcemia (>10.2 mg/dL) were significantly associated with HBS.

Conclusions

Post-parathyroidectomy HBS is common in dialysis patients with SHPT. Young age, high preoperative serum ALP and iPTH, and low preoperative serum calcium concentrations were important risk factors for HBS.

[Risk factors affecting graft survival after parathyroidectomy and parathyroid autotransplantation in patients on maintenance hemodialysis]

OBJECTIVE

To investigate the risk factors affecting the survival of parathyroid autograft following total parathyroidectomy combined with autologous sternocleidomastoid muscle transplantation (TPTX + AT) in patients on maintenance hemodialysis (MHD) complicated with secondary hyperparathyroidism (SHPT).

OBJECTIVE

This retrospective study was conducted among the patients on maintenance hemodialysis with SHPT, who underwent successful parathyroidectomy and autotransplantation from January, 2010 to February, 2020 in our hospital. The clinical data and serum levels of calcium, phosphorus, intact parathyroid hormone, hemoglobin, and alkaline phosphatase (ALP) of the patients were collected. The enrolled patients were divided into survival group with bilateral forearm parathyroid hormone (iPTH) ratio > 1.5 and death group with a ratio < 1.5 at 2 weeks after surgery for comparison of the clinical data and perioperative indicators. The risk factors of postoperative parathyroid autograft survival were analyzed using logistic regression analysis.

OBJECTIVE

A total of 87 patients were included in the study, among whom the graft survival rate after parathyroid transplantation was 78.16%. In both groups, serum levels of calcium, phosphorus, iPTH and ALP decreased and hemoglobin level increased significantly at 1 week and 1, 2, 3, 6 and 12 months after surgery (P < 0.01). Logistic regression analysis showed that serum ALP level was an independent risk factor for graft survival following parathyroid autotransplantation [OR=1.003, 95% CI: 1.001-1.005, P=0.004].

OBJECTIVE

TPTX+AT is a safe and effective treatment for SHPT, and parathyroid autografts are less likely to survive following parathyroid transplantation in patients with high preoperative level of ALP.

Predictors of early postoperative hypocalcemia in patients with secondary hyperparathyroidism undergoing total parathyroidectomy

OBJECTIVE

To summarize the clinical features of secondary hyperparathyroidism (SHPT) in patients with chronic renal failure and to explore the predictive factors of postoperative hypocalcemia after total parathyroidectomy in these patients.

METHODS

The clinical data of 87 patients admitted to Guangdong Electric Power Hospital from May 2013 to February 2020 were reviewed. All patients underwent total parathyroid resection and sternocleidomastoid microtransplantation. Age, sex, and the serum calcium, phosphorus, alkaline phosphatase (ALP), and intact parathyroid hormone (iPTH) concentrations were analyzed as predictive factors of postoperative hypocalcemia.

RESULTS

Bone pain was the most common clinical manifestation in this study population, and all 87 patients experienced relief from their clinical symptoms after the surgical procedure. Age and the preoperative serum calcium, ALP, and iPTH concentrations were determined to be early predictive factors of postoperative hypocalcemia.

CONCLUSIONS

Age and the preoperative calcium, ALP, and iPTH concentrations are independent risk factors for postoperative hypocalcemia in patients with SHPT and renal disease who undergo total parathyroidectomy with sternocleidomastoid microtransplantation. These factors can help identify high-risk patients who can be managed by a multidisciplinary team to improve graft survival and quality of life.

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.

Risk factors predicting severe hypocalcemia after total parathyroidectomy without autotransplantation in patients with secondary hyperparathyroidism

Objective

This study was performed to investigate the risk factors for severe hypocalcemia (SH) after total parathyroidectomy without autotransplantation (TPTX) in patients with secondary hyperparathyroidism.

Methods

We retrospectively analyzed the records of 136 patients with secondary hyperparathyroidism treated by TPTX. The patients were categorized as having SH or non-SH based on their postoperative blood calcium concentration. The risk factors for SH were identified by comparing the clinical characteristics between the two groups and by performing multiple logistic regression analyses.

Results

After surgery, 46.0% of the patients had hypocalcemia and 31.7% had SH. Evidence of renal osteodystrophy on lumbar radiographs and the serum concentrations of intact parathyroid hormone (iPTH), calcium, and alkaline phosphatase (ALP) were different between the two groups. The SH group had higher preoperative iPTH and ALP concentrations than the non-SH group. In addition, more patients with SH showed renal osteodystrophy. Logistic regression analyses indicated that preoperative hypocalcemia and a high ALP concentration were independent predictors of SH.

Conclusion

Preoperative hypocalcemia and a high ALP concentration were identified as risk factors for SH following TPTX.

Risk Factors for Prolonged Length of Stay and Readmission After Parathyroidectomy for Renal Secondary Hyperparathyroidism

BACKGROUND

Population-based analyses of 30-day outcomes after parathyroidectomy for renal secondary hyperparathyroidism are limited. We sought to identify risk factors associated with prolonged length of stay (LOS) and readmission in this patient population.

METHODS

Patients with secondary hyperparathyroidism who underwent parathyroidectomy were reviewed in the ACS-NSQIP database (2011-2016). Patients were identified by ICD codes specific to secondary hyperparathyroidism of renal origin and the ACS-NSQIP variable for current preoperative dialysis. Multivariable logistic regression was used to identify independent factors associated with prolonged LOS and 30-day readmission after parathyroidectomy.

RESULTS

The cohort included 1846 patients with secondary hyperparathyroidism on dialysis who underwent parathyroidectomy. There were 416 (22.5%) patients classified under the prolonged LOS group. On multivariable analysis, factors associated with prolonged LOS included elevated preoperative alkaline phosphatase [OR 3.13 (95%-CI 2.09-4.70), p < 0.001], decreased preoperative hematocrit [OR 1.83 (95%-CI 1.25-2.68), p = 0.002], unplanned reoperation (OR 5.02 [95%-CI 2.22-11.3], p < 0.001) and any postoperative complication [OR 6.12 (95%-CI 3.31-11.3), p < 0.001]. The overall 30-day readmission rate was 15.0%. Hypocalcemia and hungry bone syndrome accounted for 47.0% (n = 93/198) of readmissions. On multivariable analysis, patients with a history of hypertension and those undergoing unplanned reoperation were at risk of readmission [2.16 (95%-CI 1.21-3.87), p = 0.009, and 2.40 (95%-CI 1.15-5.02), p = 0.020, respectively], whereas reoperative parathyroidectomy was inversely associated with readmission (OR 0.24, 95%-CI 0.07-0.80, p = 0.021).

CONCLUSION

In patients undergoing parathyroidectomy for renal secondary hyperparathyroidism, several readily available preoperative biochemical markers, including those of increased bone turnover and anemia, are associated with prolonged postoperative LOS. Unplanned reoperation was predictive of both increased LOS and readmission.

A Nomogram to Predict Hungry Bone Syndrome After Parathyroidectomy in Patients With Secondary Hyperparathyroidism

BACKGROUND

Parathyroidectomy (PTX) has been demonstrated as an effective treatment for patients with secondary hyperparathyroidism (SHPT) of renal origin. However, severe hypocalcemia, called hungry bone syndrome (HBS), is a common complication following PTX in these patients and can lead to poor clinical outcomes, even death. Therefore, exploring risk factors for HBS and establishing a prediction nomogram allow intensive monitoring and prompt treating this postoperative complication, which is the main purpose of this study.

METHODS

From October 2016 to October 2018, PTX with autotransplantation (PTX + AT) procedures were performed in 131 patients with SHPT of renal origin by a surgeon and his team in the Thyroid and Parathyroid Surgery Center, West China Hospital, Sichuan University, China. After applying the inclusion and exclusion criteria, a total of 114 patients were enrolled for analyses in this study. Comprehensive data including preoperative, intraoperative, and postoperative variables were prospectively collected and retrospectively analyzed. The univariate and multivariate logistic regression analyses with internal validation by bootstrapping were used to confirm independent risk factors for postoperative HBS. The nomogram was developed based on the statistical analysis results. Receiver operator characteristic (ROC) curves were drawn to compare the prediction performance among different predictors.

RESULTS

The occurrence of postoperative HBS was 76.3% (87 out of 114 patients) in this study. Univariate analysis showed that preoperative intact parathyroid hormone (iPTH), serum alkaline phosphatase, bone-specific alkaline phosphatase (bone-ALP) were significantly higher in HBS group than those in non-HBS group, while preoperative corrected serum calcium and albumin were significantly lower in HBS group than those in non-HBS group. Total weight of resected parathyroid glands was significantly heavier in HBS group versus non-HBS group. Multivariate logistic regression analysis with internal validation by bootstrapping demonstrated preoperative iPTH, bone-ALP, preoperative corrected serum calcium, and total weight of resected parathyroid glands were independently associated with postoperative HBS. The nomogram including the abovementioned four independent predictors was constructed and showed better prediction performance than the other four predictors in terms of postoperative HBS.

CONCLUSIONS

On the basis of this study, we found higher preoperative iPTH level, higher bone-ALP level, heavier total weight of resected parathyroid glands, and lower preoperative corrected serum calcium level were independent predictors of postoperative HBS in patients with SHPT of renal origin. The nomogram can expediently, accurately, and objectively predict the risk of postoperative HBS in individual patient with SHPT of renal origin.

Predictors of early postoperative hypocalcemia after total parathyroidectomy in renal hyperparathyroidism

Purpose

Patients with secondary hyperparathyroidism are at high risk for developing postoperative hypocalcemia. However, there are limited data regarding predictors of postoperative hypocalcemia in renal failure patient with secondary hyperparathyroidism. This study aimed to determine the clinical presentations of renal hyperparathyroidism and the predictors of early postoperative hypocalcemia after total parathyroidectomy.

Methods

Data of patients with renal hyperparathyroidism who underwent total parathyroidectomy between January 2007 to December 2014 were reviewed retrospectively. Patients were divided into 2 cohort groups according to their serum calcium levels within 24 hours of parathyroidectomy: the hypocalcemia group (calcium levels of 2 mmol/L or less), and the normocalcemia group (calcium levels more than 2 mmol/L). With the use of multivariable logistic regression analyses, the predictors of early postoperative hypocalcemia after total parathyroidectomy in patients with renal hyperparathyroidism were investigated.

Results

Among 68 patients, 56 patients (82.4%) were symptomatic preoperatively. Fifty patients (73.5%) presented with bone pain and 14 patients (20.6%) had muscle weakness. Early postoperative hypocalcemia occurred in 25 patients (36.8%). Preoperative alkaline phosphatase level was the predictor of early postoperative hypocalcemia (adjusted odds ratio, 1.004; 95% confidence interval, 1.001–1.006; P = 0.002).

Conclusion

Results from our study show that most of the patients with renal hyperparathyroidism were symptomatic preoperatively and the most common clinical presentations were bone pain and muscle weakness. The significant predictor of early postoperative hypocalcemia after total parathyroidectomy was the preoperative alkaline phosphatase levels.

Relationship between parathyroid oxyphil cell proportion and clinical characteristics of patients with chronic kidney disease

BACKGROUND

Parathyroid glands consist of chief cells and oxyphil cells. The parathyroid oxyphil cell proportion increased dramatically in patients with chronic kidney disease (CKD). The importance of the oxyphil cell in the treatment of secondary hyperparathyroidism (SHPT) has been enhanced in recent years. The aim of this study was to explore the possible relationship between parathyroid oxyphil cell proportion and clinical features of patients with CKD.

METHODS

From December 2010 to December 2018, 78 consecutive patients with CKD 5 who underwent parathyroidectomy (PTX) were reviewed. None of the patients had used Cinacalcet. Patients were divided into two groups according to their parathyroid oxyphil cell proportion. The mean parathyroid oxyphil cell proportion of all the patients was obtained. Group 1 consisted of 37 patients, the parathyroid oxyphil cell proportion of whom was more than or equal to mean proportion. Group 2 consisted of 41 patients, the parathyroid oxyphil cell proportion of whom was less than mean proportion. The demographic and biochemical data of the two groups were compared.

RESULTS

Preoperative parathyroid hormone (PTH) and total weight of removed parathyroid glands in the patients of group 1were less than those in group 2. There was no difference between the two groups in terms of preoperative calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), age and dialysis years.

CONCLUSION

The parathyroid oxyphil cell proportion was associated with preoperative PTH and total weight of removed parathyroid glands in the patients with CKD. Patients with more parathyroid oxyphil proportion had lower preoperative PTH level and smaller total weight of the removed parathyroid glands.

Effects of parathyroidectomy on tumoral calcinosis in uremic patients with secondary hyperparathyroidism

BACKGROUND

Tumoral calcinosis (TC) is a rare disease derived from uremic secondary hyperparathyroidism (SHPT). However, parathyroidectomy (PTX) seems to be ineffective at relieving TC in some patients. In this study, we investigated the relationship between PTX and TC shrinkage.

METHODS

We retrospectively followed up nine TC patients who underwent PTX, dividing them into two groups: those with TC size reduced by > 80% were in the "effective group" (group A), and the rest in the "ineffective group" (group B).

RESULTS

We enrolled nine patients (7 men; mean age 38.6 ± 10.9 years) with SHPT-related TC. One patient with calciphylaxis was excluded due to sudden death. The efficiency of PTX in causing TC regression was 62.5% (5 patients in group A). Group A had a shorter overall duration of TC (6 [5.5, 6.0] vs. 9 [8.0, 10.0] months; P = 0.02) and higher serum levels of alkaline phosphatase (ALP; 408.0 [217.9, 1101.7] vs. 90.8 [71.0, 102.1] pg/ml; P = 0.03) and high-sensitivity C-reactive protein (hs-CRP; 82.7 [55.0, 112.4] vs. 3.1 [3.1, 4.5] mg/l; P = 0.02). Average calcium supplementation within 1 week of surgery was significantly greater in group A than in group B (96.8 [64.1, 105.3] vs. 20.1 [13.1, 32.7] g; P = 0.04). Patients in both the groups demonstrated similar serum phosphate levels before PTX, but these levels were higher in group B than in group A at follow-up times (3 months, P = 0.03; 6 months, P = 0.03).

CONCLUSIONS

The shorter duration of pre-existing TC and higher ALP levels before PTX, as well as lower serum phosphate levels after PTX, were correlated with effective SHPT-TC shrinkage.

Calcitriol loading before total parathyroidectomy with autotransplant in patients with end-stage kidney disease: does it prevent postoperative hypocalcaemia?

BACKGROUND

Hungry bone syndrome (HBS) is one of the most serious complications following parathyroidectomy for severe hyperparathyroidism. There is a lack of literature informing the treatment and risk factors for this condition and the ideal pre-operative strategy for prevention.

AIMS

The primary aims were to examine the incidence of HBS with pre-operative calcitriol loading for 10 days and to determine the risk factors for HBS. The secondary aims were to determine the rate of intravenous calcium replacement in those with HBS and to assess whether cinacalcet removal has increased rates of parathyroidectomy in the end-stage kidney disease population.

METHODS

We performed a retrospective study from 2011 to 2018 on 45 patients with end-stage kidney disease undergoing total parathyroidectomy with autotransplantation for severe hyperparathyroidism. This was based at the John Hunter and Newcastle Private Hospitals in New South Wales.

RESULTS

28.3% of patients with calcitriol loading undergoing parathyroidectomy fulfilled criteria for HBS. Pre-operative variables that were associated with HBS were elevated parathyroid hormone (P = 0.028) and longer duration of renal replacement therapy (P = 0.033). Rates of total parathyroidectomy were higher after the removal of calcimimetics from the Pharmaceutical Benefits Scheme (P = 0.0024).

CONCLUSIONS

HBS remains a common complication of parathyroidectomy, even with prolonged high-dose calcitriol loading. This emphasises the need for further trials investigating other targeted therapies, such as bisphosphonates, to prevent HBS. Those most at risk of HBS are patients with high bone turnover and prolonged renal replacement therapy.

Preoperative calcitriol reduces postoperative intravenous calcium requirements and length of stay in parathyroidectomy for renal-origin hyperparathyroidism

BACKGROUND

Patients undergoing subtotal parathyroidectomy for renal-origin hyperparathyroidism often develop postoperative hypocalcemia, requiring calcitriol and intravenous calcium (Postop-IVCa). We hypothesized that in subtotal parathyroidectomy for renal-origin hyperparathyroidism, preoperative calcitriol treatment reduces the use of postoperative administration of intravenous calcium.

METHODS

A retrospective chart review compared subtotal parathyroidectomy for renal-origin hyperparathyroidism patients who received preoperative calcitriol treatment with those patietns who did not receive preoperative calcitriol treatment at one institution. Preoperative calcitriol treatment loading doses were 0.5 mcg twice daily for 5 days. All patients received postoperative calcitriol and oral calcium carbonate. Postoperative administration of intravenous calcium was given for symptoms, calcium <7.0 mg/dL, or surgeon preference. The Fisher exact test was used to compare proportions. The Wilcoxon test was used to compare continuous data. Multivariable logistic regression adjusted for confounders.

RESULTS

Included were 81 patients who received subtotal parathyroidectomy for renal-origin hyperparathyroidism (41 patients who received preoperative calcitriol treatment, 40 patients who did not receive preoperative calcitriol treatment). Preoperative calcitriol treatment use increased over time (0% 2004-2010, 69% 2011-2016). Groups who received preoperative calcitriol treatment and groups who did not receive preoperative calcitriol treatment were similar in preoperative serum calcium, vitamin D, parathyroid hormone, and median age (P > .05 for all). Patients who received preoperative calcitriol treatment less often required postoperative administration of intravenous calcium (34% vs 90% of patients who did not receive preoperative calcitriol treatment, P < .001). Median length of stay was 2.0 days shorter for patients who received preoperative calcitriol treatment versus patients who did not receive preoperative calcitriol treatment patients (P < .001). Factors associated with postoperative administration of intravenous calcium included not receiving preoperative calcitriol treatment, low preoperative calcium, and high preoperative parathyroid hormone. After multivariable adjustment, preoperative calcitriol treatment remained independently associated with reduced postoperative administration of intravenous calcium (OR 0.02, P < .001).

CONCLUSION

Preoperative calcitriol therapy lowered use of postoperative administration of intravenous calcium by 56% and length of stay by 50% in subtotal parathyroidectomy for renal-origin hyperparathyroidism patients. We believe preoperative calcitriol treatment should become standard of care for subtotal parathyroidectomy for renal-origin hyperparathyroidism.

Hypocalcemia-based prediction of hungry bone syndrome after parathyroidectomy in hemodialysis patients with refractory secondary hyperparathyroidism

Objective

This study was performed to explore the risk factors for hungry bone syndrome (HBS) and establish prediction equations for calcium supplementation after parathyroidectomy in hemodialysis patients with secondary hyperparathyroidism.

Methods

We retrospectively analyzed data from 252 hemodialysis patients undergoing successful total parathyroidectomy with autotransplantation. HBS was defined according to a minimum postoperative serum corrected calcium (PcCa) concentration of <2.0 mmol/L. Independent predictors of HBS were analyzed, and prediction equations for HBS were derived accordingly.

Results The incidence of HBS was 71.4%. The serum corrected calcium and preoperative serum alkaline phosphatase (ALP) concentrations were independent predictors of HBS. The preoperative serum ALP, intact parathyroid hormone (iPTH), and hemoglobin concentrations were independent factors influencing the average descending velocity of the PcCa concentration before calcium supplementation (PcCa-V), intravenous calcium supplement holding time (IVCa-T), and intravenous calcium supplement dosage (IVCa), while the serum ALP and iPTH concentrations were independent predictors of the oral calcium supplement dosage (OCa). Four prediction equations for PcCa-V, IVCa-T, IVCa, and OCa were established.

Conclusions

Establishment of prediction equations for HBS may contribute to a new individualized therapy for patients with HBS.

Risk factors for severe hypocalcemia after parathyroidectomy in dialysis patients with secondary hyperparathyroidism

Severe hypocalcemia (SH) is a common and serious complication in dialysis patients with secondary hyperparathyroidism (SHPT) after parathyroidectomy (PTX). The aim is to explore the risk predictors of SH in post-PTX dialysis ESRD patients with SHPT. 129 consecutive dialysis patients with SHPT underwent PTX were retrospectively reviewed. A total of 22 clinical parameters were included in the study. SH was defined as the minimum values of serum calcium lower than 1.875 mmol/L (7.5 mg/dL) after surgery. Univariate analysis showed that pruritus, lumbar X-ray changes of renal osteodystrophy, pre- and post-operative intact parathyroid hormone (iPTH), Calcium, alkaline phosphatase, and gland mass were significantly different between SH and non-SH groups. In the multivariate logistic regression model, the pre-operative serum iPTH, calcium, and pruritus were independent risk predictors of SH. AUCs for pre-operative serum iPTH, calcium and pruritus were 0.810, 0.714 and 0.591, respectively. Patients with higher level of pre-operative serum iPTH, lower level of serum calcium and with no/mild symptoms of pruritus are at greater risk of developing SH after PTX.

Persistent hypocalcemia and hungry bone syndrome after parathyroidectomy and renal transplantation in a patient with end-stage renal disease

Hungry bone syndrome (HBS) defines as persistent and severe hypocalcemia after parathyroidectomy surgery. It is treated by oral or venous discrimination of calcium carbonate. The present treatment is mostly effective. Hereby, we describe a 60-year-old man who had developed hyperparathyroidism secondary to end-stage renal disease and then parathyroidectomy was performed for him twice before renal transplantation. Up to 500 vials of calcium gluconate (100 mg/ml calcium gluconate 10%) were administered for him to control serum calcium level after parathyroidectomy and renal transplantation. Furthermore, high-dose calcium carbonate was administered for his outpatient care. Therefore, HBS, which was resistant to standard treatment, was detected for him.

Risk Factors for Elevated Preoperative Alkaline Phosphatase in Patients with Refractory Secondary Hyperparathyroidism

Elevated preoperative levels of alkaline phosphatase (ALP) in patients with refractory secondary hyperparathyroidism are correlated with postoperative hypocalcemia and mortality. The aim of this study was to identify the predictors of preoperative ALP in patients with secondary hyperparathyroidism. From April 2012 to December 2015, 220 patients with refractory secondary hyperparathyroidism undergoing total parathyroidectomy without autotransplantation were reviewed. A total of 164 patients presented with elevated preoperative ALP. Univariate analysis showed that patients with elevated ALP were significantly younger. The elevated ALP group had significantly higher levels of preoperative parathyroid hormone (PTH), lower preoperative serum calcium, higher preoperative phosphorus, lower postoperative hypocalcemia, and a longer hospital stay. Logistic regression analysis showed that elevated preoperative PTH was a significant independent risk factor for elevated preoperative ALP (P = 0.000), and its value of 1624 pg/mL was the optimal cutoff point. Factors predictive of elevated preoperative ALP in patients with secondary hyperparathyroidism include preoperative PTH. Earlier surgery, aggressive calcium supplementation, and more careful or aggressive postoperative care for high-risk patients are needed.

Parathyroidectomy for the treatment of hyperparathyroidism: Thirty-day morbidity and mortality

OBJECTIVES/HYPOTHESIS

Evaluate morbidity and mortality rates for patients with different levels of hyperparathyroidism (HPT) undergoing parathyroidectomy (PTX), specifically comparing primary hyperparathyroidism to secondary and tertiary hyperparathyroidism. Assess predictive factors of increased morbidity and mortality.

STUDY DESIGN

Retrospective national database review.

METHODS

Patients undergoing PTX, defined by Current Procedural Terminology codes 60500, 60502, 60505, for the treatment of HPT, were identified in the American College of Surgeons National Surgical Quality Improvement Program database between 2006 and 2014. Incidence of morbidity and mortality was calculated for primary, secondary, and tertiary HPT. A t test, analysis of variance, and χ² analyses were used to assess preoperative characteristics among the three groups.

RESULTS

A total of 21,267 patients were included in the analysis. There was an overall 7.2% morbidity and mortality rate, including 45 (0.21%) deaths, a 1.8% readmission rate, and a 1.9% reoperation rate, but morbidity and mortality rates were widely divergent when comparing primary to secondary and tertiary HPT. PTX resulted in a 4.9% morbidity and mortality rate for primary HPT (n = 14,500), 26.8% morbidity and mortality rate for secondary HPT (n = 1661), and 21.8% morbidity and mortality rate for tertiary HPT (n = 588). The primary reason for readmission was hypocalcemia (18.3%). Hematoma (7.2%) and postoperative hemorrhage (3.3%) were the two most common causes of reoperation. Elevated preoperative serum creatinine, alkaline phosphatase, and hypertension resulted in a higher rate of complications after PTX (P < .0001).

CONCLUSIONS

Although surgery for primary HPT is an extremely common and safe procedure with minimal morbidity and mortality rates, PTX for secondary and tertiary HPT has significantly higher rates of morbidity and mortality, requiring special attention in the postoperative period. Predictive factors of poor outcomes include hypertension, elevated creatinine, and elevated alkaline phosphatase.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:528-533, 2018.

Peripherally inserted central catheters for calcium requirements after successful parathyroidectomy: a comparison with centrally inserted catheters

BACKGROUND Intravenous calcium supplements are often required following parathyroidectomy to avoid postoperative hypocalcaemia. The aim of this study was to compare application effect of a femoral central venous catheter (CVC) and peripherally inserted central catheter (PICC) on intravenous calcium supplements after parathyroidectomy. METHODS We retrospectively reviewed the hospital records of 73 patients with secondary hyperparathyroidism who underwent a successful parathyroidectomy at the Huashan Hospital attached to Fudan University between 1 April 2011 and 1 February 2016. RESULTS Of the 73 study participants, 39 (53.4%) had a PICC and 34 (46.6%) had a CVC, respectively. Patients in the CVC group needed 6-7 days of intravenous calcium supplements, while patients in PICC group needed only 2-3 days to achieve normal serum calcium concentration (2.2-2.6 mmol/L). Furthermore, the duration of calcium supplementation was 71.62 ± 4.48 hours in PICC group and 100.4 ± 5.43 hours in CVC group (P < 0.05). Of the patients in PICC group, the incidence of catheter occlusion, operation failure and hypocalcaemia was 0%, which was significantly lower than those in CVC group (2.56%, 7.69% and 7.69%, respectively). CONCLUSIONS PICC is a safe and efficient alternative in contrast to CVC for providing venous access for calcium supplementation in surgical patients after parathyroidectomy.

Risk factors and clinical course of hungry bone syndrome after total parathyroidectomy in dialysis patients with secondary hyperparathyroidism

Background

Hungry bone syndrome (HBS) is an important postoperative complication after parathyroidectomy for severe secondary hyperparathyroidism (SHPT). There is, however, little data in the literature on its detailed clinical course, and the associated risk factors remain controversial.

Methods

We did a single-center retrospective study on 62 consecutive dialysis patients who underwent total parathyroidectomy for SHPT to examine the risk factors, clinical course and outcome. Data on demographic characteristics, perioperative laboratory parameters including serum calcium, phosphate, alkaline phosphatase (ALP) and parathyroid hormone (PTH), drug treatment for SHPT and operative details of parathyroidectomy were collected.

Results

Seventeen (27.4%) patients developed severe postoperative hypocalcemia with HBS. The serum calcium dropped progressively while serum ALP rose after operation until 2 weeks later when serum calcium reached the trough and serum ALP peaked. Serum phosphate also fell but stabilized between 4 and 14 days. The total postoperative calcium and vitamin D supplementation was significantly larger, and hospital stay was significantly longer in the group with HBS as compared with those without HBS. Young age, high body weight, high preoperative ALP level, and low preoperative calcium level independently predicted the development of HBS while preoperative PTH and use of cinacalcet or paricalcitol did not.

Conclusion

HBS was common after total parathyroidectomy in patients with SHPT, and it is important to closely monitor the postoperative serum calcium, phosphate and ALP levels in the following 2 weeks, especially for those at risk. The implications of our findings on perioperative management are discussed.

Surgical management of secondary hyperparathyroidism in chronic kidney disease--a consensus report of the European Society of Endocrine Surgeons

BACKGROUND

Despite advances in the medical management of secondary hyperparathyroidism due to chronic renal failure and dialysis (renal hyperparathyroidism), parathyroid surgery remains an important treatment option in the spectrum of the disease. Patients with severe and complicated renal hyperparathyroidism (HPT), refractory or intolerant to medical therapy and patients with specific requirements in prospect of or excluded from renal transplantation may require parathyroidectomy for renal hyperparathyroidism.

METHODS

Present standard and actual controversial issues regarding surgical treatment of patients with hyperparathyroidism due to chronic renal failure were identified, and pertinent literature was searched and reviewed. Whenever applicable, evaluation of the level of evidence concerning diagnosis and management of renal hyperparathyroidism according to standard criteria and recommendation grading were employed. Results were discussed at the 6th Workshop of the European Society of Endocrine Surgeons entitled Hyperparathyroidism due to multiple gland disease: An evidence-based perspective.

RESULTS

Presently, literature reveals scant data, especially, no prospective randomized studies to provide sufficient levels of evidence to substantiate recommendations for surgery in renal hyperparathyroidism. Appropriate surgical management of renal hyperparathyroidism involves standard bilateral exploration with bilateral cervical thymectomy and a spectrum of four standardized types of parathyroid resection that reveal comparable outcome results with regard to levels of evidence and recommendation. Specific patient requirements may favour one over the other procedure according to individualized demands.

CONCLUSIONS

Surgery for patients with renal hyperparathyroidism in the era of calcimimetics continues to play an important role in selected patients and achieves efficient control of hyperparathyroidism. The overall success rate and long-term control of renal hyperparathyroidism and optimal handling of postoperative metabolic effects also depend on the timely indication, individually suitable type of parathyroid resection and specialized endocrine surgery.

Risk factors for severe hypocalcemia after parathyroidectomy in prevalent dialysis patients with secondary hyperparathyroidism

PURPOSE

Hypocalcemia is one of the common complications after parathyroidectomy (PTX). Severe hypocalcemia (SH) can lead to tetany, cardiac arrhythmia and even sudden death. However, predictors for the development of SH in patients with secondary hyperparathyroidism demonstrated in some small-scale studies with a limited sample size remain inconclusive.

METHODS

A retrospective chart review of 420 consecutive dialysis patients who underwent PTX during a 12-year period was performed. We checked serum levels of calcium (Ca), phosphorus (P), alkaline phosphatase (ALP) and intact parathyroid hormone (iPTH) for three consecutive days postoperatively. SH was defined as the minimum values of serum calcium lower than 1.875 mmol/L (7.5 mg/dL) within 3 days after operation.

RESULTS

The mean (±SD) age of our study population was 53 ± 12 years, and more than half (57 %) were female. SH occurred in 37 % of the patients after PTX. Using a multivariate stepwise logistic regression analysis, lower preoperative levels of Ca (odds ratio 0.69, 95 % CI 0.60-0.79, P < 0.001), higher preoperative levels of iPTH (odds ratio 1.04, 95 % CI 1.00-1.07, P = 0.048), P (odds ratio 2.43, 95 % CI 1.49-3.95, P < 0.001) and ALP (odds ratio 1.08, 95 % CI 1.05-1.11, P < 0.001) were found to be independent predictors of occurrence of SH following PTX.

CONCLUSIONS

The readily obtainable preoperative laboratory parameters including Ca, iPTH, P, and ALP will allow identification of a subgroup of patients who are at greater risk for the development of SH following PTX.

Incidence of and risk factors for hungry bone syndrome in 84 patients with secondary hyperparathyroidism

Introduction

Secondary hyperparathyroidism develops in nearly all patients with end-stage renal disease. Parathyroidectomy is often performed when medical therapy fails. The most common postoperative complication, hungry bone syndrome (HBS), requires early recognition and treatment.

Materials and methods

A total of 84 patients who underwent parathyroidectomy because of secondary hyperparathyroidism were investigated. Detailed analysis of laboratory parameters (calcium, phosphate, parathyroid hormone, hemoglobin, and urea levels) and baseline characteristics (age at time of surgery, duration of renal replacement therapy, and medication) was performed to detect preoperative predictors for the development of HBS.

Results

Average overall follow-up of the cohort was 4.7 years. Within this time frame, 13 of 84 patients had to undergo a second surgery because of recurrent disease, and HBS occurred in 51.2%. Only decreased preoperative calcium levels and younger age at time of surgery were significant predictors of HBS. Minimal levels of calcium were detected 3 weeks after surgery. Preoperative vitamin D therapy could not prevent HBS and could not shorten the duration of intravenous calcium supplementation.

Conclusion

HBS is a very common complication after parathyroidectomy. Younger patients and patients with low preoperative calcium levels were at higher risk for the development of HBS. Remarkably, preoperative vitamin D therapy could not prevent HBS and had no impact on the length of intravenous calcium supplementation. Intensive monitoring of calcium levels must be performed for at least 3 weeks after surgery.

Postoperative hungry bone syndrome in patients with secondary hyperparathyroidism of renal origin

BACKGROUND

Hungry bone syndrome (HBS) is a postoperative condition of severe hypocalcemia that can be seen in patients who have undergone parathyroidectomy (PTX) for secondary hyperparathyroidism (2HPT) of renal origin. This study examines HBS in patients after PTX for 2HPT.

METHODS

Prospectively collected data was retrospectively reviewed in patients who underwent PTX for 2HPT of renal origin at a single institution. HBS was defined as the need for additional days of hospitalization or readmission for intravenous calcium supplementation due to clinical symptoms of hypocalcemia, including tingling, muscle spasms, and bone pain and/or immediate postoperative low serum calcium ≤7.5 mg/dl.

RESULTS

Of 79 patients who underwent PTX for 2HPT, 27.8% (n = 22) experienced HBS. Young age (≤45 years, p = 0.02) was the only preoperative variable that predicted HBS. Most patients developed HBS within 18 h after surgery and required a prolonged hospital stay (19/22) compared to those requiring hospital readmission within the first 7 days (3/22). Initial postoperative serum calcium levels within 18 h of surgery were significantly lower in those patients who developed HBS (7.1 vs. 8.3 mg/dl, p = 0.001), and those patients also had a greater absolute decrease in serum calcium (2.8 vs. 3.5 mg/dl, p = 0.04).

CONCLUSION

HBS develops in a significant proportion of patients generally within the first 18 h after subtotal PTX for 2HPT. The only identifiable preoperative risk factor for HBS was young age. Additionally, low initial calcium levels and greater absolute decrease in serum calcium may help identify those patients that will develop HBS requiring judicious calcium supplementation.