One-hour PTH after thyroidectomy predicts symptomatic hypocalcemia

A Parathyroid Hormone-guided Calcium and Calcitriol Supplementation Protocol Reduces Hypocalcemia-related Readmissions Following Total Thyroidectomy

OBJECTIVE

To determine the effect of a 4 hour postoperative serum parathyroid hormone (PTH) guided calcium and calcitriol supplementation protocol on the incidence of hypocalcemia and hospital readmissions in patients undergoing total thyroidectomy.

METHODS

This was a single institution, retrospective chart review of patients who underwent total thyroidectomy, 148 had been operated on prior to the protocol implementation and 389 after. Hypocalcemia risk was stratified as low (PTH >30 pg/ml), medium (15-30 pg/ml), and high (<15 pg/ml), using serum PTH values obtained 4 hours postoperatively. Hypocalcemia was defined as a total serum calcium level <8 mg/dl. Baseline demographic and operative characteristics, and postoperative outcome were recorded for both groups. Fisher's exact test or Wilcoxon rank sum test were used to compare the characteristics of the two groups. A multivariable logistic regression model was applied to account for potentially confounding variables.

RESULTS

Postoperative hypocalcemia occurred significantly less frequently in the protocol group compared to the preprotocol group (10.3% vs. 20.9%, P=.002). The reduction in hypocalcemia in the protocol group was observed both in patients with (16.3% vs. 25.6%) and without (8.4% vs. 19.3%) cervical lymph node dissection. There was a significantly lower incidence of hospital readmission events in the protocol group compared to the preprotocol group (1.0% vs. 4.7%, P=.013).

CONCLUSIONS

Compared to a historical cohort, a PTH-guided protocol for calcium and calcitriol supplementation significantly reduces postoperative hypocalcemia and hospital readmission rates, in patients undergoing total thyroidectomy.

Predictive value of 6 h postoperative parathyroid hormone level on permanent hypoparathyroidism in pediatric total thyroidectomy: a pilot study

OBJECTIVES

Transient hypocalcemia is a common complication after pediatric total thyroidectomy, while permanent hypoparathyroidism (PH) is relatively uncommon. To date there is no model to predict which patients will develop PH based on post-operative makers. We aim to identify pediatric patients who are at high risk of PH following thyroidectomy based on 6 h post-operative parathyroid hormone (PTH) value.

METHODS

A retrospective review of 122 pediatric patients undergoing total thyroidectomy between 2016 and 2022 following implementation of a multidisciplinary team was performed. Outcome of interest was permanent hypoparathyroidism, defined as need for calcium supplementation at 6 months postoperatively. Receiver operating characteristic (ROC) analysis was used to determine PTH value at 6 h post-operative that was predictive of permanent hypoparathyroidism.

RESULTS

Rates of permanent hypoparathyroidism reported are similar to those described in the literature with 12 patients (10.9%) developing PH. In patients who developed PH, mean 6 h postoperative PTH was 5.12 pg/mL. Mean 6 h postoperative PTH level in those who did not develop PH was 31.34 pg/mL (p<0.0001). The 6 h post-operative PTH value predictive for PH was ≤11.3 pg/mL. PTH cutoff of ≤11.3 pg/mL had a sensitivity of 100%, specificity of 72.2%, positive predictive value (PPV) of 27.0%, and negative predictive value (NPV) of 100%.

CONCLUSIONS

6 h postoperative PTH values were found to be predictive of permanent hypoparathyroidism in pediatric total thyroidectomy: a 6 h postoperative PTH level of >11.3 pg/mL excludes permanent hypoparathyroidism, but if PTH is ≤11.3 pg/mL at 6 h, approximately 1/3 of patients may persist with permanent hypoparathyroidism.

Intact Parathyroid Hormone Levels in Predicting Postoperative Hypocalcaemia After Total Thyroidectomy in South Indian Population: Cross Sectional Study

Hypocalcaemia being one of the most common complications after total thyroidectomy may not be avoidable in all cases. This study evaluated the effectiveness of intact Parathyroid hormone (iPTH) measured at 1-h after total thyroidectomy in predicting postoperative hypocalcaemia in early postoperative period in South Indian population. Patients who underwent total thyroidectomy in our institute from 2016 to 2018 were included. Preoperative calcium and iPTH levels were measured. Patients' iPTH level was measured 1 h after surgery and serum calcium level was measured at 24 h after surgery. Patients were also monitored clinically for any symptoms and signs of hypocalcaemia. A total of 57 patients were studied. The malignant causes accounted for 75.4% with papillary carcinoma thyroid being the most common cause. 65.7% of patients who underwent total thyroidectomy and 100% of patients who underwent total thyroidectomy with neck dissection developed hypocalcaemia. 70% of patients with low iPTH developed hypocalcaemia and none of the patients who had normal iPTH developed hypocalcaemia. This relation was statistically significant with p value of 0.018 (< 0.05). The positive predictive value is 70% and negative predictive value is 100%. Though our study supports the hypothesis that iPTH is effective in predicting hypocalcaemia after total thyroidectomy in the early postoperative period, a larger sample study is needed to further support this. It can be used to consider patients for early discharge or to prophylactically start oral calcium and Vitamin D supplementation based on iPTH levels at 1 h after surgery.

Definition and diagnosis of postsurgical hypoparathyroidism after thyroid surgery: meta-analysis

Background

Postsurgical hypoparathyroidism (PH) is the most frequent complication after thyroid surgery. The aim of this systematic review and meta-analysis is to summarize a unifying definition of PH and to elucidate the best possible approach for early detection of PH.

Methods

A systematic review of the literature according to the PICO framework using Embase, PUBMED and the Cochrane library was carried out on 1 December 2021 followed by analysis for risk of bias, data extraction and meta-analysis. All studies addressing the definition of postoperative hypoparathyroidism and/or diagnostic approaches for early detection and diagnosis were included. Case reports, commentaries, non-English articles, book chapters and pilot studies and reviews were excluded.

Results

From 13 704 articles, 188 articles were eligible for inclusion and further analysis. These articles provided heterogeneous definitions of PH. Meta-analysis revealed that postoperative measurements of parathormone (PTH) levels have a higher sensitivity and specificity than intraoperative PTH measurements to predict PH after thyroid surgery. None of the timeframes analysed after surgery within the first postoperative day (POD1) was superior to predict the onset of PH. PTH levels of less than 15 pg/ml and less than 10 pg/ml are both reliable threshold levels to predict the postoperative onset of PH. A relative reduction of mean(s.d.) PTH levels from pre- to postoperative values of 73 (standard deviation 11) per cent may also be predictive for the development of PH. The estimation of calcium levels on POD1 are recommended.

Conclusion

PH is best defined as an undetectable or inappropriately low postoperative PTH level in the context of hypocalcaemia with or without hypocalcaemic symptoms. PTH levels should be measured after surgery within 24 h. Both threshold levels below 10 and 15 pg/ml or relative loss of PTH before/after thyroid surgery are reliable to predict the onset of PH.

Identification of secondary predictive factors for acute hypocalcemia following thyroidectomy in patients with low postoperative parathyroid hormone levels without overt calcium deficiency: A cohort study

BACKGROUND

The transient acute hypocalcemia (HypoCa) is the most prevalent complication after total thyroidectomy, detected primarily by subnormal intact parathyroid hormone (iPTH) and calcium levels. However, the need for calcium supplementation is ambiguous in patients who exhibit low iPTH with normal calcium levels. The aim of this study was to evaluate complementary predictors of HypoCa in this scenario.

METHODS

A retrospective cohort study with of 1597 consecutive patients undergoing total thyroidectomy, with or without neck dissection, from January 2014 to December 2018 at a single institution. Patients with an iPTH <12 pg/mL and a total calcium level ≥8 mg/dL in the first 8 h after surgery were included.

RESULTS

1597 patients identified with low postoperative iPTH without overt calcium deficiency was diagnosed. The transient HypoCa in that specific subgroup was 509 (31.9%). Multivariate analysis indicated that HYPOCA was associated with bilateral level VI neck dissection and pre- to postoperative calcium reduction >38 pg/mL. To better illustrate the model, we plotted a nomogram with the variables selected for the final model.

CONCLUSION

Total thyroidectomy patients who exhibit low postoperative iPTH levels without overt calcium deficiency should be considered for calcium replacement therapy when they a marked drop in iPTH postoperatively and underwent bilateral level VI neck dissection.

Can preoperative 25-hydroxyvitamin D levels predict transient hypocalcemia after total thyroidectomy?

Transient postoperative hypocalcemia is a common complication after total thyroidectomy. Evidence on contributing metabolic factors is contradictory. Our work aims to define the role of preoperative 25-hydroxyvitaminD levels in developing transient postoperative hypocalcemia. 183 consecutive patients who underwent total thyroidectomy at our institution (May 2017–December 2019) were included in the retrospective study. We reported gender, age, estimated glomerular filtration rate, creatinine, preoperative 25-hydroxyvitaminD, serum pre- and postoperative calcium, pre- and postoperative PTH levels and transient postoperative hypocalcemia occurrences. We compared variables both among patients with and without transient postoperative hypocalcemia and between patients with different 25-hydroxyvitaminD levels (< 10 ng/ml deficitary; 11–30 ng/ml insufficient; > 30 ng/ml, normal). A binomial logistic regression model evaluating the risk for transient postoperative hypocalcemia was elaborated. Patients with transient postoperative hypocalcemia had lower levels of postoperative PTH (p < 0.001) and more frequently normal or deficitary 25-hydroxyvitaminD levels (p = 0.05). When comparing patients according to their 25-hydroxyvitaminD levels, insufficiency was associated with a lower rate of transient postoperative hypocalcemia (p = 0.05); deficiency was associated with higher preoperative PTH (p = 0.021), postoperative PTH (p = 0.043) and estimated glomerular filtration rate (p = 0.031) and lower serum creatinine (p = 0.014). In the regression model higher preoperative PTH (OR = 1.011, p = 0.041) and 25-hydroxyvitaminD deficiency (OR = 0.343, p = 0.011) significantly predicted transient postoperative hypocalcemia. Data analysis revealed a correlation between transient postoperative hypocalcemia and 25-hydroxyvitaminD levels: our work points towards the possibility to stratify the risk of transient postoperative hypocalcemia according to patients’ preoperative 25-hydroxyvitaminD status.

Risk Factors for Low Levels of Parathyroid Hormone after Surgery for Thyroid Cancer: A Single Center Study

Background: Thyroidectomy is the definitive treatment for most patients with thyroid cancer. Hypoparathyroidism is the most frequent complication of thyroidectomy, and its pathogenesis is multifactorial. The aim of this study is to evaluate the patient- and surgical-related risk factors for hypoparathyroidism after surgery for thyroid cancer. Methods: In this retrospective study, patients referred to surgery for thyroid cancer from 2016 to 2019 were enrolled. Preoperative serum calcium and parathyroid hormone (PTH) and postoperative 24 h PTH and calcium levels were evaluated. Demographic data, type of surgery, incidence of hypoparathyroidism and hypocalcemia were recorded for all the patients. Patients were divided into two groups based on post-operative PTH levels (≤12 and >12 pg/mL). Results: A total of 189 patients were enrolled in this study. There were 146 women (87.3%) and 43 men (22.7%), with a mean age of 51.3 years. A total of 79 patients (41.7%) underwent a neck dissection. A total of 59 patients (31.1%) had a postoperative PTH level < 12 pg/mL. Female sex, neck dissection, the yield of lymph node dissection and incidental parathyroidectomy were significantly associated with postoperative hypoparathyroidism. Incidental parathyroidectomy was reported in 44 (23.2%) patients and was correlated with younger age (<40 years) and neck dissection. There was no difference in the rate of post-operative hypocalcemia between patients with incidental parathyroidectomy and those without. Conclusions: Young patients undergoing neck dissection and with incidental parathyroidectomy have the highest risk of postoperative hypoparathyroidism after surgery for thyroid cancer. However, a large proportion of patients without incidental parathyroidectomy may have temporary hypocalcemia, suggesting that impaired blood supply of parathyroid glands during their identification and dissection may play a relevant role.

The Effect of Parathyroid Gland Autotransplantation on Hypoparathyroidism After Thyroid Surgery for Papillary Thyroid Carcinoma

Purpose

There are some controversies over the relationship between parathyroid gland autotransplantation and permanent hypoparathyroidism. This study aimed to explore the relationship between parathyroid gland autotransplantation and postoperative hypoparathyroidism.

Patients and Methods

We performed a retrospective analysis of patients who underwent initial thyroid surgery for papillary thyroid carcinoma from January 2014 to December 2018. Patients were divided into 4 groups according to the number of autotransplanted parathyroid glands (group 1: 0 autotransplanted parathyroid gland, group 2: 1 autotransplanted parathyroid gland, group 3: 2 autotransplanted parathyroid glands, group 4: 3 autotransplanted parathyroid glands). Clinical data were analyzed among the four groups.

Results

The more parathyroid glands were transplanted, the higher the incidence of immediate hypoparathyroidism was (group 1: 32.9%, group 2: 52.9%, group 3: 65.8%, group 4: 82.4%; P_{group 1 vs group 2} < 0.001, P_{group 2 vs group 3} = 0.012, P_{group 3 vs group 4} = 0.17). Parathyroid gland autotransplantation did not affect the incidence of permanent hypoparathyroidism (group 1: 1.4%, group 2: 1.3%, group 3: 0.9%, group 4: 0%; P_{group 1 vs group 2} > 0.99, P_{group 2 vs group 3} > 0.99, P_{group 3 vs group 4} > 0.99).

Conclusion

The number of autotransplanted parathyroid glands was positively associated with the incidence of postoperative immediate hypoparathyroidism. Parathyroid gland autotransplantation was not associated with permanent hypoparathyroidism.

Predicting risk factors of postoperative hypocalcemia after total thyroidectomy: is safe discharge without supplementation possible? A large cohort study

PURPOSE

With increasing economic pressures to shorten the length of hospital stay, there has been much recent interest in studying risk factors for the development of postoperative hypocalcemia after total thyroidectomy. The aim of this study was to investigate whether serum calcium and/or PTH levels can predict post-thyroidectomy hypoparathyroidism.

METHODS

From January to December 2014, 477 consecutive patients undergoing total thyroidectomy were included. Corrected calcemia and PTH were systematically performed on postoperative day 1/(POD1). Symptomatic patients were treated on POD1 or POD2 with calcium and vitamin D.

RESULTS

Sixty-eight patients (14.25%) were treated for postoperative hypocalcemia. No patients with calcemia ≥ 2.16 mmol/l and PTH ≥ 1.9 pmol/l were supplemented and therefore were safely discharged on POD1 (specificity = 100%). All patients with calcemia ≤ 1.89 mmol/l were treated regardless the PTH values (n = 10) (specificity = 100%). For calcium value between 1.9 and 2.16 mmol/l with a PTH > 4.7 pmol/l, nobody was treated. With a calcemia between 1.9 and 2.16 mmol/l and a PTH > 1.9 pmol/l, 44 patients did not develop any symptom. ROC curve analysis showed that combination of Cac = 2.16 mmol/l and iPTH = 4.7 pmol/l provided a sensitivity of 97.06% and a specificity of 76.53% (p < 0.0001). We therefore propose an algorithm that would allow to 70% of patients could have been discharged on POD1 without risk of hypocalcemia or overtreatment.

CONCLUSION

Combination of corrected calcemia and PTH on POD1 can efficiently predict hypocalcemia and be integrated into clinical practice for personalizing lengths of hospitalization and appropriate treatment.

TRIAL REGISTRATION

ClinicalTrials.gov PRS. Unique Identifying number or registration ID: NCT04372225.

A Cohort Study Assessing the Association Between Body Composition Parameters and Symptomatic Hypocalcemia After Total Thyroidectomy

BACKGROUND

Postoperative hypocalcemia is one of the major concerns following thyroidectomy and the most frequent cause of prolonged hospital stay. The aim of this study was to evaluate the relationship between body composition parameters and symptomatic hypocalcemia following total thyroidectomy. In addition, the effects of disease- and patient-related factors on hypocalcemia were investigated.

METHODS

A total of 144 patients were prospectively included between March 2014 and September 2017. Patients were divided into 2 groups according to the presence or absence of clinical symptoms of hypocalcemia. Subsequently, the relationship between body composition parameters and hypocalcemia was evaluated.

RESULTS

Postoperative hypocalcemia-related symptoms occurred in 28 patients (19.4%). Permanent hypocalcemia was not encountered in any patient. Patients with hypocalcemic symptoms were more likely to have nodules ≥40 mm (39.3% vs. 17.2%, P = .011), retrosternal goiters (25.0% vs. 7.8%, P = .017), central lymph node dissection (LND) (32.1% vs. 11.2%, P = .015), and parathyroid autotransplantation (28.6% vs. 3.4%, P < .001) than those without symptoms. However, no differences were observed in the body composition parameters between symptomatic and asymptomatic patients. On multivariate analysis, lower preoperative intact parathyroid hormone (iPTH) levels (odds ratios (ORs) .96, 95% confidence intervals (CIs) .93-.99), the presence of retrosternal goiters (OR 10.26, 95% CI 2.23-47.14), central LND (OR 16.05, 95% CI 3.90-66.07), and parathyroid autotransplantation (OR 36.22, 95% CI 6.76-194.13) predicted hypocalcemia.

DISCUSSION

This study demonstrates that patients with lower preoperative iPTH levels, retrosternal goiters, central LND, and parathyroid autotransplantation are at an increased risk of developing clinical symptoms of hypocalcemia. Body composition parameters have no effect on the incidence of hypocalcemia after total thyroidectomy.

Predictors of post-thyroidectomy hypocalcaemia: a systematic and narrative review

OBJECTIVE

Hypocalcaemia is the most common complication after total or completion thyroidectomy. This study assesses recent evidence on predictive factors for post-thyroidectomy hypocalcaemia in order to identify the patients affected and aid prevention.

METHOD

Two authors independently assessed articles and extracted data to provide a narrative synthesis. This study was an updated systematic search and narrative review regarding predictors of post-thyroidectomy hypocalcaemia using the Ovid Medline, Embase, Cochrane and Cinahl databases. Results were limited to papers published from January 2012 to August 2019.

RESULTS

Sixty-three observational studies with a total of 210 401 patients met the inclusion criteria. The median incidence was 27.5 per cent for transient biochemical hypocalcaemia, 12.5 per cent for symptomatic hypocalcaemia and 2.2 per cent for permanent hypocalcaemia. The most frequent statistically significant predictor of hypocalcaemia was peri-operative parathyroid hormone level. Symptomatic hypocalcaemia and permanent hypocalcaemia were seen more frequently in patients undergoing concomitant neck dissection.

CONCLUSION

Many factors have been studied for their link to post-thyroidectomy hypocalcaemia, and this study assesses the recent evidence presented in each case.

Prediction of post-idroidectomy hypocalcemia through rapid PTH determination

INTRODUCTION

Hypocalcemia is the most frequent complication after thyroidectomy. The aim of this work is to identify biochemical risk factors of hypocalcemia using quick perioperative (pre and post-thyroidectomy) intact parathyroid hormone (PTHi) and postoperative calcemias.

METHODS

In a consecutive series of 310 total thyroidectomies, samples of quick PTHi at the anaesthetic induction and 10 minutes after surgery, together with serum calcemias every 12 hours were obtained. The sensitivity, specificity, positive and negative predictive value are analyzed and related to hypocalcemia. A control group of hemithyroidectomies is also analyzed to compare the effects of surgery on PTH secretion.

RESULTS

Of the 310 patients, 202 (65.1%) remained normocalcemic and asymptomatic (group A), 108 (34.9%) presented hypocalcemia (Group B), requiring oral calcium (79 symptomatic). After analysis of several cut-off points, combining a PTHr drop gradient of 60% or calcemia inferior to 7.4 mg/dl at 24 hours, a sensitivity of 100% is achieved without leaving false negatives. Compared to the control group, there is a significant difference with respect to the post-operative calcemias and PTHr, p < 0.001.

CONCLUSIONS

Total thyroidectomy affects parathyroid function with evident decrease in rPTH and risk of hypocalcemia. The combination of PTHr decrease of 60% or less than 7.4 mg/dl calcemia at 24 hours gives a 100% sensitivity for predicting patients at risk of hypocalcemia.

Parathyroid Hormone Reduction Predicts Transient Hypocalcemia after Total Thyroidectomy: A Single-Center Prospective Study

OBJECTIVE

We performed this study to investigate the risk factors for postoperative hypocalcemia after total thyroidectomy with central lymph node dissection (CLND). Study Design. This was a single-center prospective study based on 176 consecutive patients who underwent total thyroidectomy for papillary thyroid carcinoma. Setting. Patients were recruited between January 2016 and June 2018. Subjects and Methods. Patients who underwent bilateral (n = 155, bilateral group) and ipsilateral CLND (n = 21) after total thyroidectomy were included. The preoperative and postoperative parathyroid hormone (PTH) and calcium levels were detected. The risk factors for transient hypocalcemia were identified using logistic regression analysis and receiver operating characteristic (ROC) curve analysis.

RESULTS

Fifty-one (28.98%) patients developed transient hypocalcemia, and 2 patients (1.14%) developed permanent hypoparathyroidism. There was no difference in the gender ratio or the morbidity of hypocalcemia between the patients who underwent bilateral and ipsilateral CLND. On postoperative day 1, PTH decrease was a risk factor for transient hypocalcemia in the whole cohort (β = 0.043, OR = 1.044, 95% CI 1.023-1.065, p < 0.001), bilateral group (β = 0.042, OR = 1.043, 95% CI 1.022-1.064, p < 0.001), and female patients (β = 0.049, OR = 1.050, 95% CI 1.026-1.075, p < 0.001). Tumor diameter was a risk factor for transient hypocalcemia in female patients (β = 0.499, OR = 1.647, 95% CI 1.003-2.704, p=0.049). The ROC curve analysis illustrated that 65.58%, 71.00%, and 71.00% PTH level reduction had high accuracy in predicting transient hypocalcemia in the whole cohort, bilateral group, and female patients, respectively (AUC = 0.986, 0.987, and 0.987).

CONCLUSION

Asymptomatic female patients with bilateral CLND and a 71.00% PTH level reduction were at a high risk of transient hypocalcemia.

Preoperative vitamin D levels do not relate with the risk of hypocalcemia following total thyroidectomy. A cohort study

BACKGROUND

Hypocalcemia is the most common complication following total thyroidectomy. Few factors may relate with increased risk of postoperative hypocalcemia. Preoperative vitamin D values have been evaluated in few studies, but reports present conflicting data. Aim of our study is to evaluate the association of preoperative vitamin D values and hypocalcemia following total thyroidectomy.

METHODS

A retrospective analysis of patients undergoing total thyroidectomy in our department of endocrine surgery between November 2012 and November 2015 was performed.

RESULTS

Mean age of patients was 56.2 years (±14.0) and sex ratio (F:M) was 4.3:1. Sixty-four patients (17.4%) had preoperative vitamin D insufficiency (x<25 nmol/L), 138 patients (37.5%) vitamin D deficiency (25<x<50 nmol/L) and 166 patients (45.1%) vitamin D sufficiency (x>50 nmol/L). Following total thyroidectomy for both benign and malignant pathology, 66 patients (17.9%) had symptomatic hypocalcemia (x<2.0 mmol/L) requiring medical treatment (group 1), 64 patients (17.4%) biochemical hypocalcemia (2<x<2.1 mmol/L) not requiring treatment (group 2) and 238 patients (64.7%) had normal levels (x>2.1 mmol/L, group 3). Mean postoperative PTH value was 25.4 pg/ml (range 2-61). No statistical correlation between postoperative serum calcium and preoperative vitamin D values (R=-0.001, P=0.9849) was found nor associations were found regarding age, sex, type of thyroid disease or BMI.

CONCLUSIONS

In our cohort of patients, preoperative vitamin D levels were not associated with a higher risk of hypocalcemia following total thyroidectomy. Postoperative PTH appears to be the most sensible item to predict the risk of postoperative symptomatic hypocalcemia.

The effectiveness of parathyroid gland autotransplantation in preserving parathyroid function during thyroid surgery for thyroid neoplasms: A meta-analysis

Objective

We conducted this meta-analysis to assess the effectiveness of parathyroid gland autotransplantation in preserving parathyroid function during thyroid surgery for thyroid neoplasms.

Methods

We conducted a search by using PubMed, Embase, and the Cochrane Library electronic databases for studies that were published up to January 2019. The reference lists of the retrieved articles were also reviewed. Two authors independently assessed the methodological quality and extracted the data. A random-effects model was used to calculate the overall combined risk estimates. Publication bias was evaluated with a funnel plot using Egger’s and Begg’s tests.

Results

A total of 25 independent studies involving 10,531 participants were included in the meta-analysis. Compared with patients who did not undergo parathyroid gland autotransplantation, the overall pooled relative risks for patients who underwent parathyroid gland autotransplantation were 1.75 (95% CI: 1.51–2.02, p<0.001) for postoperative hypoparathyroidism, 1.72 (95% CI: 1.45–2.05, p<0.001) for protracted hypoparathyroidism, 1.06 (95% CI: 0.44–2.58, p = 0.894) and 0.71 (95% CI: 0.22–2.29, p = 0.561) for biochemical hypoparathyroidism and biochemical hypocalcemia at 6 months postoperatively, respectively, and 1.89 (95% CI: 1.33–2.69, p<0.001) and 0.22 (95% CI: 0.09–0.52, p = 0.001) for biochemical hypoparathyroidism and biochemical hypocalcemia at 12 months postoperatively, respectively. The pooled relative risks for patients who underwent one parathyroid gland autotransplantation and patients who underwent two or more parathyroid gland autotransplantations were 1.71 (95% CI: 1.25–2.35, p = 0.001) and 2.22 (95% CI: 1.43–3.45, p<0.001) for postoperative hypoparathyroidism, 1.09 (95% CI: 0.59–2.01, p = 0.781) and 0.55 (95% CI: 0.16–1.87, p = 0.341) for hypoparathyroidism at 6 months postoperatively compared with those of patients who did not undergo parathyroid gland autotransplantation.

Conclusions

Parathyroid gland autotransplantation is significantly associated with increased risk of postoperative and protracted hypoparathyroidism, and the number of autoplastic parathyroid glands is positively correlated with the incidence of postoperative hypoparathyroidism.

Considerations for Thyroidectomy as Treatment for Graves Disease

Hyperthyroidism is a clinical state that results from abnormally elevated thyroid hormones. Thyroid gland affects many organ systems; therefore, patients usually present with multiple clinical manifestations that involve many organ systems such as the nervous, cardiovascular, muscular, and endocrine system as well as skin manifestations. Hyperthyroidism is most commonly caused by Graves disease, which is caused by autoantibodies to the thyrotropin receptor (TRAb). Other causes of hyperthyroidism include toxic multinodular goiter, toxic single adenoma, and thyroiditis. Diagnosis of hyperthyroidism can be established by measurement of thyroid-stimulating hormone (TSH), which will be suppressed with either elevated free T4 and/or T3 (overt hyperthyroidism) or normal free T3 and T4 (subclinical hyperthyroidism). Hyperthyroidism can be treated with antithyroid drugs (ATDs), radioactive iodine (RAI), or thyroidectomy. ATDs have a higher replacement rate when compared with RAI or thyroidectomy. Recent evidence has shown that thyroidectomy is a very effective, safe treatment modality for hyperthyroidism and can be performed as an outpatient procedure. This review article provides some of the most recent evidence on diagnosing and treating patients with hyperthyroidism.

Variation of Thyroidectomy-Specific Outcomes Among Hospitals and Their Association With Risk Adjustment and Hospital Performance

Importance

Current surgical quality metrics might be insufficient to fully judge the quality of certain operations because they are not procedure specific. Hypocalcemia, recurrent laryngeal nerve (RLN) injury, and hematoma are considered to be the most relevant outcomes to measure after thyroidectomy. Whether these outcomes can be used as hospital quality metrics is unknown.

Objectives

To evaluate whether thyroidectomy-specific outcomes vary among hospitals, whether the addition of thyroidectomy-specific variables affects risk adjustment, and whether differences in hospital performance are associated with thyroidectomy-specific care processes.

Design, Setting, and Participants

In this retrospective cohort study, patients undergoing thyroidectomies from January 1, 2013, through December 31, 2015, at hospitals participating in the American College of Surgeons' National Surgical Quality Improvement Program were studied.

Exposure

Thyroidectomy-related care.

Main Outcomes and Measures

Clinically severe hypocalcemia, RLN injury, and clinically significant hematoma within 30 days of thyroid surgery and hospital-level performance variation, change in risk adjustment, and association with processes.

Results

Overall, 14 540 patients (mean [SD] age, 52.1 [15.0] years; 11 499 [79.1%] female) underwent operations at 98 hospitals. Because operations missing thyroidectomy-specific outcomes were excluded, the numbers of operations and hospitals analyzed differed by outcome. Of 14 540 operations included, clinically severe hypocalcemia occurred in 450 patients (3.3% overall, 0.6% after partial, and 4.7% after subtotal or total thyroidectomy), RLN injury in 755 patients (5.7% overall, 4.2% after partial, and 6.6% after subtotal or total thyroidectomy), and hematoma in 175 patients (1.3%). Hospital performance varied for hypocalcemia and RLN injury but not for hematoma. Hospital performance rankings were largely unaffected by the inclusion of thyroidectomy-specific data in risk adjustment. With regard to processes, patients undergoing thyroidectomies at the best-performing vs worst-performing hospitals less frequently had their postoperative parathyroid hormone level measured (593 [19.9%] vs 457 [31.7%], P < .001) and more often were prescribed oral calcium, vitamin D, or both (2281 [76.6%] vs 962 [66.8%], P < .001). When profiled by RLN injury, use of energy devices (1517 [69.1%] vs 507 [55.2%], P < .001) and intraoperative nerve monitoring (1223 [55.7%] vs 346 [37.7%], P < .001) were more prevalent at the best- compared with the worst-performing hospitals.

Conclusions and Relevance

Postoperative hypocalcemia and RLN injury, but not hematoma, potentially could be used as thyroidectomy-specific national hospital quality improvement metrics. Strategies aimed at reducing these complications after thyroidectomy may improve the care of these patients.

Stratifying the Risk of Developing Clinical Hypocalcemia after Thyroidectomy with Parathyroid Hormone

Objective

To identify the risk of clinical hypocalcemia in the first hours after thyroidectomy.

Study Design

Prospective observational study.

Setting

Single-institution tertiary hospital in Madrid, Spain.

Subjects and Methods

A total of 123 patients who underwent total or completion thyroidectomy between June 2010 and March 2012 were included. Pre- and postoperative intact parathyroid hormone (iPTH) levels were obtained. Patients remain hospitalized a minimum of 48 hours until blood calcium stabilized. Calcium and/or vitamin D supplements were prescribed only when signs or symptoms of hypocalcemia developed. Receiver operating characteristic curve analysis was employed to evaluate the postoperative iPTH level and the pre- to postoperative decrease in iPTH levels. Two cutoff values were determined to stratify the risk of developing clinical hypocalcemia into 3 groups.

Results

The areas under the receiver operating characteristic curve were 0.991 for the postoperative iPTH and 0.998 for the decrease in iPTH. An iPTH decrease of 80% had 100% sensitivity to detect patients who developed clinical hypocalcemia, while a postoperative iPTH <3 pg/mL had 100% specificity. Thus, patients with an iPTH decrease ≤80% are at a very low risk of clinical hypocalcemia, and patients with a postoperative iPTH <3 pg/mL are at a very high risk. Patients with an iPTH decrease >80% and a postoperative iPTH ≥3 pg/mL are at intermediate risk. No significant correlation was found between the time when the sample was obtained and iPTH values.

Conclusion

This study stablishes a very accurate test to stratify the risk of clinical postthyroidectomy hypocalcemia based on pre- and postoperative iPTH levels.

Postoperative IPTH compared with IPTH gradient as predictors of post-thyroidectomy hypocalcemia

OBJECTIVES/HYPOTHESIS

Predicting patients' risk for hypocalcemia after thyroidectomy may allow for same-day discharge. This study was designed to compare postoperative intact parathyroid hormone (IPTH) alone with percentage change in IPTH (IPTH gradient) in predicting post-thyroidectomy hypocalcemia.

STUDY DESIGN

Retrospective cohort study.

METHODS

Patients undergoing total thyroidectomy by the senior author from May 2015 to May 2016 were included. Serum IPTH was measured preoperatively and 1 hour postoperatively, and IPTH gradient was calculated. Postoperative hypocalcemia was mild (≥8.0, <8.4) or severe (<8.0 and/or hypocalcemic symptoms). Postoperative IPTH and IPTH gradient were compared with hypocalcemia using logistic regression. Receiver operating characteristic analysis of IPTH measures as predictors of hypocalcemia was performed, and the area under the curve (AUC) was calculated.

RESULTS

Overall, 119 patients were included. Forty-seven percent of the patients developed postoperative hypocalcemia, including 26 (22%) with mild and 30 (25%) with severe hypocalcemia. Thirteen patients had hypocalcemic symptoms. Median IPTH gradient and postoperative IPTH each differed significantly by category of hypocalcemia (P < .001). Higher IPTH gradient was significantly associated with odds of severe and symptomatic hypocalcemia (adjusted odds ratio [aOR]: 1.21, 95% confidence interval [CI]: 1.06-1.39 and aOR: 1.34, 95% CI: 1.05-1.71 per 10% increase), whereas lower postoperative IPTH was not (aOR: 1.27, 95% CI: 0.95-1.68 and aOR: 1.44, 95% CI: 0.90-2.31 per 10 pg/mL decrease). The AUC for predicting severe hypocalcemia was nonsignificantly higher for IPTH gradient than postoperative IPTH (AUC = 0.77 vs. 0.69, P = .10). The AUC for predicting symptomatic hypocalcemia was significantly higher for IPTH gradient (AUC = 0.75 vs. 0.72, P = .03).

CONCLUSIONS

Our results suggest that the IPTH gradient may be more useful than postoperative IPTH alone in predicting risk of post-thyroidectomy hypocalcemia.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:769-774, 2018.

Early prediction of hypocalcemia following thyroid surgery. A prospective randomized clinical trial

PURPOSE

The aim of this randomized-controlled trial was to validate the results of a previous prospective single-cohort observational study conducted in the same surgical unit regarding the use of concomitant intact parathyroid hormone (iPTH) and serum calcium measurement in predicting hypocalcemia after total thyroidectomy.

METHODS

From January 2014 to January 2015, 150 patients underwent total thyroidectomy in our department and were randomized into two groups. The experimental group was submitted to iPTH assay 6 h after surgery while the control group was submitted to a daily assay of serum calcium and phosphorus. Sensitivity and specificity of different serum measurements have been calculated using the receiver-operator characteristics (ROC) curve.

RESULTS

The prevalence of hypocalcemia was 14.25% in both groups. The assay of iPTH 6 h after surgery combined with the serum calcium assay 24 h after surgery yielded the highest diagnostic accuracy in predicting hypocalcemia using ROC curves, with 100% sensitivity and 100% specificity.

CONCLUSIONS

According to our previous study, the combined measurement of iPTH 6 h after surgery and of serum calcium 24 h after surgery are highly predictive of early postoperative hypocalcemia. These results are important in selecting the patients eligible for early discharge and those who need calcium and vitamin D supplementation.