Predictors of early postoperative hypocalcemia after total parathyroidectomy in renal hyperparathyroidism

Identification of novel risk factors for postoperative severe hypocalcemia in patients with primary hyperparathyroidism undergoing parathyroidectomy: a case control study

BACKGROUND

Patients with primary hyperparathyroidism (PHPT) are at risk for severe hypocalcemia (SH) following parathyroidectomy (PTX), but limited data exist on the predictors of SH. We aimed to identify risk factors for early postoperative SH after PTX in patients with PHPT and to evaluate the predictive value of clinical parameters.

METHODS

A retrospective review of patients with PHPT who underwent PTX between January 2010 and December 2022 was performed. A total of 46 patients were included in the study, with 15 (32.6%) experiencing postoperative SH, 19 (41.3%) having calculi in the ureter or kidney, and 37 (80.4%) having osteoporosis. Patients were divided into SH and non-SH groups based on postoperative serum calcium levels. Preoperative biochemical indicators, bone turnover markers, and renal function parameters were analyzed and correlated with postoperative SH.

RESULTS

Statistically significant (P < 0.05) differences were found in preoperative serum calcium (serum Ca), intact parathyroid hormone, serum phosphorus (serum P), serum Ca/P, percentage decrease of serum Ca, total procollagen type 1 intact N-terminal propeptide, osteocalcin (OC), and alkaline phosphatase levels between the two groups. Multivariate analysis showed that serum P (odds ratio [OR] = 0.989; 95% confidence interval [95% CI] = 0.981-0.996; P = 0.003), serum Ca (OR = 0.007; 95% CI = 0.001-0.415; P = 0.017), serum Ca/P (OR = 0.135; 95% CI = 0.019-0.947; P = 0.044) and OC levels (OR = 1.012; 95% CI = 1.001-1.024; P = 0.036) were predictors of early postoperative SH. The receiver operating characteristic curve analysis revealed that serum P (area under the curve [AUC] = 0.859, P < 0.001), serum Ca/P (AUC = 0.735, P = 0.010) and OC (AUC = 0.729, P = 0.013) had high sensitivity and specificity.

CONCLUSION

Preoperative serum P, serum Ca/P and osteocalcin levels may identify patients with PHPT at risk for early postoperative SH after PTX.

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 New Calculation Model for Calcium Requirements After Parathyroidectomy in Patients With Secondary Hyperparathyroidism

OBJECTIVES

We aimed to develop a new calculation model for calcium requirements in dialysis patients following parathyroidectomy.

METHODS

A total of 98 patients with secondary hyperparathyroidism receiving parathyroidectomy from January 2014 to January 2022 were enrolled in this study. Among these patients, 78 were randomly selected for construction of the calcium requirement calculation model, and the remaining 20 patients were selected for model validation. The calcium requirement model estimated the total calcium supplementation for 1 week after surgery using variables with significant relationships in the derivation group by stepwise multiple linear regression analysis. Bias, precision, and accuracy were measured in the validation group to determine the performance of the model.

RESULTS

The model was as follows: calcium requirement for 1 week after surgery=33.798-8.929×immediate postoperative calcium+0.190×C-reactive protein-0.125×age+0.002×preoperative intact parathyroid hormone+0.003×preoperative alkaline phosphatase (R2=0.8). The model was successfully validated.

CONCLUSION

We generated a novel model to guide calcium supplementation. This model can assist in stabilizing the serum calcium levels of patients during the early postoperative period. Furthermore, it contributes to the individualized and precise treatment of hypocalcemia in patients following parathyroidectomy.

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.

Evaluation of preoperative procollagen type 1 N-terminal peptide and collagen type 1 C-telopeptide levels in the prediction of postoperative hypocalcemia in patients undergoing parathyroidectomy due to primary hyperparathyroidism

PURPOSE

This study is aimed at investigating the role of preoperative procollagen type 1 N-terminal peptide (P1NP) and collagen type 1 C-telopeptide (CTx) levels in predicting the development of postoperative hypocalcemia in primary hyperparathyroidism (PHPT).

METHODS

In this prospective observational study, preoperative complaints of patients with primary hyperparathyroidism and their urea, creatinine, glomerular filtration rate (GFR), calcium, albumin, urinary calcium, parathyroid hormone, and bone mineral density (BMD) were recorded. P1NP and CTx levels were analyzed in blood samples taken the day before surgery, and their relationship with calcium levels obtained on the first postoperative day was examined.

RESULTS

The median age was 53 years for patients who developed hypocalcemia and 62 years for those who did not develop hypocalcemia (p = 0.01). The urea, creatinine, and GFR values were determined as 22 mcg/dl, 0.61 mcg/dl, and 105 ml/min, respectively, for the hypocalcemia group (Group 1) and 30.5 mcg/dl, 0.74 mcg/dl, and 90 ml/min, respectively, for the non-hypocalcemia group (Group 2) (p = 0.02, 0.001, and 0.01, respectively). The BMD femur Z-score was - 0.1 in Group 1 and 0.8 in the Group 2 (p = 0.02). The mean CTx values were 4.14 pg/dl and 1.98 pg/dl (p = 0.036), and the mean P1NP values were 252.84 mcg/dl and 269.04 mcg/dl (p = 0.427) for Groups 1 and 2, respectively. According to multivariate analysis, only CTx was a significant independent predictor of hypocalcemia (odds ratio 1.739).

CONCLUSION

CTx level is a significant factor in predicting the risk of developing early postoperative hypocalcemia in patients scheduled for surgery due to primary hyperparathyroidism.

Risk Factor Analysis and Prediction of Severe Hypocalcemia after Total Parathyroidectomy without Auto-Transplantation in Patients with Secondary Hyperparathyroidism

OBJECTIVE

Our study aimed to develop and validate a nomogram to predict severe hypocalcemia (SH) before total parathyroidectomy (TPTX) without auto-transplantation in patients with secondary hyperparathyroidism.

METHODS

A total of 299 consecutive patients who underwent TPTX without transplantation for secondary hyperparathyroidism were selected from the General Hospital of Northern Theater Command between January 2013 and December 2021. Of these, patients who underwent surgery between January 2013 and December 2020 formed the training cohort (n = 208) to develop a nomogram, and those who underwent surgery thereafter formed the validation cohort (n = 91) to validate the performance of this nomogram. Univariate and multivariate logistic regression analyses were used to identify the risk factors associated with SH, and then, a nomogram was constructed.

RESULTS

The incidence of postoperative SH was 27.9% and 35.2% in the training and validation cohorts, respectively. The preoperative factors associated with SH were younger age, lower serum calcium (Ca) level, higher intact parathyroid hormone (iPTH) level, and higher serum alkaline phosphatase (ALP) level. Incorporating these 4 factors, the nomogram achieved good concordance indexes of 0.866 (95%CI, 0.816-0.916) and 0.867 (95% CI, 0.793-0.941) in predicting SH in the training and validation cohorts, respectively, and had well-fitted calibration curves. The positive predictive values of the nomogram were 64.7% (54.1%-78.4%) and 75.0% (58.6%-88.5%), and negative predictive values of the nomogram were 90.0% (82.9%-93.6%) and 86.4% (73.5%-94.0%) for the training and validation cohorts, respectively.

CONCLUSIONS

We developed and validated a nomogram for the prediction of SH in patients who underwent TPTX without auto-transplantation for secondary hyperparathyroidism. Our nomogram may facilitate the identification of high-risk SH in patients after TPTX and optimization of preoperative decision-making.

[Evolution of the incidence and results at 12 months of parathyroidectomy: 40 years of experience in a dialysis center with two successive surgical departments]

INTRODUCTION

Secondary hyperparathyroidism remains the main complication of mineral and bone metabolism in patients with chronic kidney disease. In case of resistance to medical treatment (native and active vitamin D, calcium and calcimimetics), surgical parathyroidectomy is indicated. The aim of this retrospective study is to show the evolution of the incidence and results of surgical parathyroidectomy in our center between 1980 and 2020 as patient characteristics, diagnostic and therapeutic strategies have changed.

PATIENTS AND METHODS

We collected data from dialysis patients who had a first surgical parathyroidectomy between 2000 and 2020 (period 2) in the same surgical department and compared them with historical data between 1980 and 1999 (period 1) operated in one other center.

RESULTS

In period 1, 53 surgical parathyroidectomy were performed (2.78/year, 0 to 5, 8.5/1000 patients-year) vs.56 surgical parathyroidectomy in period 2 (2.8/year, 0 to 9, 8/1000 patients-year). The patients of the 2 periods were comparable except for the higher dialysis vintage in period 1 (149±170 vs.89±94 months; P=0.02). In comparison with dialysis patients not requiring surgical parathyroidectomy during the same period, patients who had surgical parathyroidectomy were younger, had higher dialysis vintage and lower diabetes prevalence, but more frequently carriers of glomerulopathy or polycystosis. Systematically performed in period 2, cervical ultrasound identified at least one visible gland in 78.6% of cases while the scintigraphy, performed only in 66% of cases, found at least one gland in 81% of cases. Twelve months after surgery, PTH > 300 pg/mL (marker of secondary hyperparathyroidism recurrence or surgery failure) was present in 30% of patients in period 1 vs. 5.3% in period 2. Hypoparathyroidism was also more frequently observed in period 2 (35.7 vs. 18.8%). Surgical complications were also higher in period 1.

CONCLUSION

Despite therapeutic and strategic advances, severe secondary hyperparathyroidism is still as common as ever. It is favored by excessively high PTH targets, by suboptimal prevention before dialysis and poor tolerance of calcimimetics. The surgical parathyroidectomy is effective and safe in the hands of a specialized team with an ultrasound and scintigraphic preoperative assessment.

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.

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%.

Risk factors for hypocalcemia in dialysis patients with refractory secondary hyperparathyroidism after parathyroidectomy: a meta-analysis

Objective

Hypocalcemia after parathyroidectomy (PTX) results in tetany, diarrhea, cardiac arrhythmia, and even sudden death. However, a meta-analysis or systematic evaluation of risk factors with the occurrence and development of hypocalcemia in patients with secondary hyperparathyroidism (SHPT) after PTX has never been performed.

Methods

A thorough search of electronic databases, including PubMed, Web of Science, the Cochrane Library, and EMBASE, was performed to retrieve relevant studies from database inception to June 2021. Quality of the included studies was assessed by two independent reviewers using the Newcastle–Ottawa Scale. Review Manager 5.3 and Stata 16.0 were used for meta-analysis. The random-effects model was adopted to calculate the 95% CIs (I²> 50% or p < 0.05) of the combined effect size and the corresponding homogeneous data. Otherwise, a fixed-effects model was used.

Results

Thirteen studies including 2990 participants who met the inclusion criteria were enrolled in the present meta-analysis. The overall quality of the enrolled studies had a score of >7 points. Risk factors significantly related to hypocalcemia in patients with SHPT after PTX were preoperative serum calcium (OR 0.19, 95%CI 0.11–0.31), preoperative alkaline phosphatase (ALP) (OR 1.01, 95% CI 1.01–1.02), and preoperative intact parathyroid hormone (iPTH) (OR 1.38, 95%CI 1.20–1.58). Meanwhile, age (OR 0.97, 95%CI 0.87–1.10) was not significantly correlated with hypocalcemia after PTX.

Conclusions

Based on the current evidence, preoperative serum calcium, preoperative ALP, and preoperative iPTH were significant predictors of hypocalcemia in patients with SHPT after PTX. More attention should be given to patients with these risk factors for the prevention of postoperative hypocalcemia.

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.