Determinación de paratirina en suero como factor predictivo de hipocalcemia tras tiroidectomía total

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.

Role of oral calcium supplementation alone or with vitamin D in preventing post-thyroidectomy hypocalcaemia: A meta-analysis

BACKGROUND

Thyroidectomy is the main intervention for thyroid malignancies and some benign thyroid diseases. Its most common complication is hypocalcaemia, which requires oral or intravenous calcium therapy. The aim of this meta-analysis was to assess the efficacy of routine calcium supplementation with or without vitamin D in preventing hypocalcaemia post-thyroidectomy.

METHODS

Systematic searches of the PubMed, EMBASE, and Cochrane Library databases were performed. The qualities of the included articles were assessed using the Cochrane risk of bias tool. The studies' qualities of outcomes and strengths of evidence were evaluated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool. Data analysis was performed using Review Manager 5.3, and odds ratio (ORs) with their 95% confidence intervals (CIs) were computed for dichotomous data.

RESULTS

Ten randomized controlled trials (RCTs) were included. The combined study recruited 1620 patients (343 men and 1277 women) who underwent total thyroidectomy alone or with neck dissection. Calcium supplementation decreased the risk of transient postoperative hypocalcaemia (OR 0.48 [95% CI, 0.31-0.74]; P < .001) but did not decrease the demand for intravenous supplementation or the rate of permanent hypocalcaemia compared to no treatment. Calcium and vitamin D supplementation significantly reduced the rate of transient hypocalcaemia and the demand for intravenous supplementation compared to either no treatment (OR 0.21 [95% CI, 0.11-0.40]; P < .001 and OR 0.26 [95% CI, 0.10-0.69]; P = .007, respectively) or calcium alone (OR 0.39 [95% CI, 0.18-0.84]; P = .02 and OR 0.18 [95% CI, 0.07-0.47]; P < .001, respectively), but did not decrease the rate of permanent hypocalcaemia. GRADE-based confidence was moderate.

CONCLUSION

Postoperative calcium supplementation is effective for preventing post-thyroidectomy hypocalcaemia. Calcium plus vitamin D was more effective than calcium alone in preventing postoperative hypocalcaemia and decreasing the demand for intravenous calcium supplementation. Further, well-designed RCTs with larger sample sizes are required to validate our findings.

Predictors of postoperative hypocalcemia occurring after a total thyroidectomy: results of prospective multicenter study

BACKGROUND

Thyroid surgeries are among the most common operations performed in the world. Hypocalcemia following total thyroidectomy is a common complication that is sometimes difficult to correct. The aim of this study is to determine the risk factors for hypocalcemia following total thyroidectomy and their clinical value.

METHODS

From January 2015 through to April 2017, 400 patients were included in this prospective multicenter study. All patients underwent total thyroidectomy due to various thyroid diseases. The following risk factors were analyzed: pre-operative and post-operative biochemical blood parameters, clinical effects and factors related to surgery, the patient, and the disease.

RESULTS

Post-operative hypocalcemia developed in 257 patients (64.2%). Of them, 197 patients (76.7%) were diagnosed with asymptomatic hypocalcemia. Clinical symptoms were present in 60 of the 257 patients with hypocalcemia (23.3%). The statistically significant predictors of hypocalcemia were decreased calcium and ionized calcium pre-operatively (p < 0.001), parathyroid hormone on day one following surgery (p < 0.001), thyrotoxicosis <10 years before surgery (odds ratio 1.65, 95% CI 1.01-2.70, p = 0.046), the number of parathyroid glands found during surgery (odds ratio 0.52, 95% CI 0.38-0.70, p < 0.001), ligation of the trunk of the left inferior thyroid artery (odds ratio 2.04, 95% CI 1.27-3.29, p = 0.003), ligation of the trunk of the right inferior thyroid artery (odds ratio 2.37, 95% CI 1.47-3.81, p < 0.001), and the number of transplanted parathyroid glands (odds ratio 1.87, 95% CI 1.12-2.97, p = 0.015). In the multivariate analysis, age (odds ratio 1.05, 95% CI 1.01-1.09, p = 0.029) and gender (odds ratio 5.94, 95% CI 1.13-31.26, p = 0.035) were statistically significant predictors.

CONCLUSIONS

This study demonstrates that there is a number of different patient (gender, age, and duration of thyrotoxicosis <10 years before surgery) and surgical (number of parathyroid glands found during surgery, decreased calcium and ionized calcium before surgery, parathyroid hormone on day one following surgery, and ligation of the trunk of the left and right inferior thyroid artery) risk factors predictive of hypocalcemia following total thyroidectomy. Optimization of the surgical technique could possibly prevent the occurrence of hypocalcemia after total thyroidectomy in some cases; in other cases, identification of known risk factors post-operatively could permit early detection and effective treatment of these patients.

Effect of preoperative vitamin D deficiency on postoperative hypocalcemia after thyroid surgery

Background

Transient post thyroidectomy hypocalcemia occurs in up to 30% of patients. We evaluated the effect of vitamin D deficiency on post thyroidectomy hypocalcaemia.

Methods

This is a prospective study which was conducted from November 2010 to January 2013 and a total of 35 patients were included and data was analyzed regarding the relation between preoperative vitamin D3 levels and occurrence of post- thyroidectomy hypocalcemia. Patients were divided into two groups dependent upon the preoperative serum vitamin D level: group 1 with vitamin D levels <20 ng/ml and group 2 with serum vitamin D levels ≥20 ng/ml. Hypocalcemia was defined as a postoperative calcium level <8.5 mg/dl.

Results

There was a difference in postoperative hypocalcemia between the two vitamin D groups. In patients with serum vitamin D ≤20 ng/ml mean pre-operative and post-operative serum calcium levels were 9.3 ± 0.5 and 8.4 ± 0.58 g dl (p < .001) whereas in patients with serum vitamin D levels >20 ng/ml mean pre-operative and post-operative serum calcium were 9.52 ± 0.64 and 8.9 ± 0.5 (p = ns).

Conclusions

Pre-operative serum vitamin D levels have got positive correlation with serum calcium levels in early post-operative period. Patients with serum vitamin D levels <20 ng/ml are highly likely to develop early post-operative hypocalcaemia and the difference between pre-operative and post-operative serum calcium levels in vitamin D deficient patients was significant (p < 0.001).

Systematic review and meta-analysis of predictors of post-thyroidectomy hypocalcaemia

BACKGROUND

Hypocalcaemia is common after thyroidectomy. Accurate prediction and appropriate management may help reduce morbidity and hospital stay. The aim of this study was to perform a systematic literature review and meta-analysis of predictors of post-thyroidectomy hypocalcaemia.

METHODS

A systematic search of PubMed, EMBASE and the Cochrane Library databases was undertaken, and the quality of manuscripts assessed using a modified Newcastle-Ottawa Scale.

RESULTS

Some 115 observational studies were included. The median (i.q.r.) incidence of transient and permanent hypocalcaemia was 27 (19-38) and 1 (0-3) per cent respectively. Independent predictors of transient hypocalcaemia included levels of preoperative calcium, perioperative parathyroid hormone (PTH), preoperative 25-hydroxyvitamin D and postoperative magnesium. Clinical predictors included surgery for recurrent goitre and reoperation for bleeding. A calcium level lower than 1·88 mmol/l at 24 h after surgery, identification of fewer than two parathyroid glands (PTGs) at surgery, reoperation for bleeding, Graves' disease and heavier thyroid specimens were identified as independent predictors of permanent hypocalcaemia in multivariable analysis. Factors associated with transient hypocalcaemia in meta-analyses were inadvertent PTG excision (odds ratio (OR) 1·90, 95 per cent confidence interval 1·31 to 2·74), PTG autotransplantation (OR 2·03, 1·44 to 2·86), Graves' disease (OR 1·75, 1·34 to 2·28) and female sex (OR 2·28, 1·53 to 3·40).

CONCLUSION

Perioperative PTH, preoperative vitamin D and postoperative changes in calcium are biochemical predictors of post-thyroidectomy hypocalcaemia. Clinical predictors include female sex, Graves' disease, need for parathyroid autotransplantation and inadvertent excision of PTGs.

Intact parathyroid hormone measurement at 24 hours after thyroid surgery as predictor of parathyroid function at long term

BACKGROUND

There is no consensus about the usefulness of postoperative intact parathyroid hormone (iPTH) determination to predict permanent hypoparathyroidism (pHPP). We evaluated the value of calcium (Ca2+) and iPTH concentration at 24 hours after total thyroidectomy (TT) for predicting pHPP.

METHODS

Ca2+ and iPTH levels from 70 consecutive patients who underwent TT were measured at 24 hours and 6 months after TT.

RESULTS

Five patients (7.1%) developed pHPP. An iPTH concentration ≤5.8 pg/mL at 24 hours after TT identified patients at risk for pHPP (sensitivity, 100%; specificity, 81.5%), but it was not accurate enough to predict its development (positive predictive value, 30%). Conversely, an iPTH level >5.8 pg/mL predicted normal parathyroid function at 6 months (negative predictive value, 100%). Compared with iPTH, a postoperative Ca2+ level ≤1.95 mmol/L was 60% sensitive and 78.5% specific to predict pHPP.

CONCLUSIONS

An iPTH concentration >5.8 pg/mL on the first postoperative day rules out pHPP with much better diagnostic accuracy than Ca2+. Postoperative iPTH could be helpful in identifying patients at risk for developing pHPP.

Parathyroid hormone decline 4 hours after total thyroidectomy accurately predicts hypocalcemia

BACKGROUND

The level of parathyroid hormone (iPTH) serum has been controversial in the prediction of postthyroidectomy hypocalcemia. Analysis of the decrease between preoperative and postoperative iPTH levels should be more accurate. Therefore, the aim of our study was to prospectively establish the reliability of the iPTH decrease for early diagnosis of postoperative hypocalcemia and to identify the patients who are not at risk for hypocalcemia.

METHODS

A prospective study of 137 consecutive patients who underwent total thyroidectomy was performed. Serum iPTH level was measured preoperatively and 4 hours postoperatively (iPTH(H4)). The sensitivity, specificity, and positive and negative predictive values for the iPTH(H4) and for the iPTH decline were estimated by confidence interval from thresholds determined by ROC curve analysis.

RESULTS

Thirty-nine patients developed hypocalcemia (28.5%). Patients who developed hypocalcemia had a significantly lower iPTH(H4) and a significantly greater iPTH decrease (P < .001). The thresholds enabling prediction of hypocalcemia were 19.4 ng/L for iPTH(H4) and 68.5% for iPTH decline. Sensitivity, specificity, and positive and negative predictive values for iPTH(H4) were 84.6%, 92.9%, 82.5%, and 93.8% (overall accuracy, 90.5%). iPTH decline was more accurate to predict hypocalcemia (sensitivity, 97.4%; specificity, 95.9%; positive predictive values 90.5%; negative predictive values, 98.6%; and overall accuracy, 96.4%).

CONCLUSION

The decrease in iPTH is more precise than the iPTH(H4) alone and can accurately predict hypocalcemia after total thyroidectomy. Patients with a decrease in iPTH less than 68.5% can be discharged at postoperative day one without any supplementation. Patients with iPTH decline more than 68.5% should be administered calcium and vitamin D supplementation before symptoms appear.