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

Effectiveness of prophylactic calcium and vitamin D supplementation for preventing post-thyroidectomy hypocalcemia: a meta-analysis

Background: Postsurgical hypocalcemia is the most common and troublesome consequence of thyroidectomy. We investigated the potential role of routine calcium or vitamin D supplementation in preventing postsurgical hypocalcemia. Methods: We searched MEDLINE and Embase for English-language publications using the keywords “calcium,” “vitamin D,” and “thyroid cancer.” The primary outcome was any postoperative hypocalcemia, and the secondary outcome was symptomatic hypocalcemia. Results: Four studies that included 381 patients were eligible for this meta-analysis. A random-effects model showed no significant difference in the occurrence of hypocalcemia between calcium/vitamin D treatment and placebo/no treatment. However, the occurrence of symptomatic hypocalcemia was lower in patients with calcium/vitamin D treatment. In the combined results, preoperative calcium and vitamin D supplementation were associated with a reduced incidence of symptomatic hypocalcemia. Conclusions: Our findings support the use of preoperative calcium and vitamin D supplementation in conjunction with routine postsurgical supplementation for patients after total thyroidectomy.

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.

PTH Gradient as a Predictor of Post Thyroidectomy Hypocalcemia

BACKGROUND

Post thyroidectomy hypocalcemia is a common complication. Post thyroidectomy PTH estimation at varying cut offs and time have been used to predict hypocalcemia and aid in early and safe discharge. Single post thyroidectomy PTH values may be spuriously normal or high in a patient that subsequently develops unanticipated low calcium levels. This study aimed to evaluate the percentage change in preoperative and postoperative PTH (Gradient) in predicting post thyroidectomy hypocalcemia.

METHODS

Forty-one patients of thyroidectomy had PTH preoperatively, postoperatively one-hour (PTH0) and day 1 (PTH1). PTH gradient was calculated as percentage change in postoperative PTH to preoperative (PTHG0, PTHG1). Hypocalcemia was categorized into mild or severe based on corrected calcium values and presence of clinical signs and/or symptoms of hypocalcemia.

RESULTS

Ten (24.3%) and 11 (26.8%) patients had mild and severe hypocalcemia, respectively. PTHG0 and PTHG1 were significantly associated with risk for hypocalcemia (P-0.006 vs P-0.002). Higher PTH0 and PTH1 gradients were significantly associated with risk of hypocalcemia (PTH0 gradient OR-0.006, 95% CI 0.00-0.175, P-0.006; PTH1 gradient OR- 0.008, 95% CI 0.00-0.166, P-0.002). PTH0 gradient was the best predictor of hypocalcemia (AUC 0.855, SE-0.065, 95% CI0.710 to 0.945, P value <0.001) and PTH1 value was a better predictor of severe/clinical hypocalcemia (AUC 0.844, SE-0.072, 95% CI 0.697 to 0.938, P- value-0.001). Based on ROC, cutoffs of PTH0 gradient and PTH1 gradient for predicting hypocalcemia and severe/clinical hypocalcemia were taken as 60% and 75%, respectively (sensitivity 70%, specificity 90.5% for hypocalcemia; sensitivity 65%, specificity 90.9% for severe hypocalcemia).

CONCLUSION

PTH gradient may be a better predictor of hypocalcemia and PTH1 gradient of >75% correlates with high risk of severe/clinical post thyroidectomy hypocalcemia.

Association of Hypocalcemia and Magnesium Disorders With Thyroidectomy in Commercially Insured Patients

Importance

Hypocalcemia is a common complication of total thyroidectomy.

Objectives

To identify factors associated with hypocalcemia after total thyroidectomy and to explore the association between hypocalcemia, magnesium disorders, and costs of care.

Design, Setting, and Participants

A retrospective cross-sectional analysis was performed using data from the MarketScan Commercial Claim and Encounters database on 126 766 commercially insured patients younger than 65 years undergoing total thyroidectomy between January 1, 2010, and December 31, 2012. Statistical analysis was performed from January 1, 2016, to May 30, 2019.

Main Outcomes and Measures

Short- and long-term hypocalcemia and the costs of care were examined using multivariable regression modeling.

Results

Among the 126 766 patients in the study (81.6% women; mean age, 46.5 years [range, 18-64 years]), postoperative hypocalcemia was present in 19.1% of patients in the initial 30-day postoperative period and in 4.4% of patients at 1 year. Magnesium disorders were present in 2.1% of patients at the time of surgery. Short- and long-term hypocalcemia were significantly more likely in women (short-term: odds ratio [OR], 1.39 [95% CI, 1.29-1.50]; long-term: OR, 1.69 [95% CI, 1.52-1.89]), those younger than 40 years (short-term: OR for ages 40-64 years, 0.83 [95% CI, 0.78-0.87]; long-term: OR for ages 40-64 years, 0.73 [95% CI, 0.67-0.79]), those with a diagnosis of thyroiditis (short-term: OR, 1.48 [95% CI, 1.16-1.89]; long-term: OR, 1.60 [95% CI, 1.13-2.26]) or cancer (short-term: OR, 1.32 [95% CI, 1.05-1.67]; long-term: OR, 1.17 [95% CI, 0.83-1.63]), vitamin D deficiency (short-term: OR, 1.96 [95% CI, 1.74-2.21]; long-term: OR, 3.72 [95% CI, 3.30-4.18]), concurrent lateral neck dissection (short-term: OR, 1.51 [95% CI, 1.37-1.66]; long-term: OR, 1.95 [95% CI, 1.69-2.26]), concurrent central neck dissection (short-term: OR, 1.15 [95% CI, 1.07-1.24]; long-term: OR, 1.25 [95% CI, 1.12-1.40]), intraoperative parathyroid (short-term: OR, 1.58 [95% CI, 1.46-1.71]; and long-term: OR, 2.05 [95% CI, 1.82-2.31]) or recurrent laryngeal nerve injury (short-term: OR, 1.49 [95% CI, 1.27-1.74]; long-term: OR, 2.04 [95% CI, 1.64-2.54]), and magnesium disorders (short-term: OR, 8.40 [95% CI, 7.21-9.79]; long-term: OR, 25.23 [95% CI, 19.80-32.17]). Compared with the initial postoperative period, the odds of hypocalcemia decreased by 90.0% (OR, 0.10 [95% CI, 0.09-0.11]) at 6 months and 93.0% (OR, 0.07 [95% CI, 0.06-0.08]) at 1 year. After controlling for all other variables, magnesium disorders were associated with the highest odds of short- and long-term postoperative hypocalcemia. Hypocalcemia ($3392) and magnesium disorders ($14 314) were associated with increased mean incremental 1-year costs of care.

Conclusions and Relevance

Hypocalcemia is common after total thyroidectomy but resolves in most patients by 1 year. Magnesium disorders are significantly independently associated with short- and long-term hypocalcemia and are associated with greater costs of care. These data suggest a potentially modifiable target to reduce the incidence and cost of long-term hypocalcemia at patient and systemic levels.

Transoral Thyroidectomy: Safety and Outcomes of 200 Consecutive North American Cases

BACKGROUND

North American adoption of the transoral endoscopic thyroidectomy vestibular approach (TOETVA) has been limited due to concerns regarding the generalizability of published outcomes, as data are predominantly from Asian cohorts with a different body habitus. We describe our experience with TOETVA in a North American population in the context of the conventional transcervical approach thyroidectomy (TCA).

STUDY DESIGN

Cases of TOETVA and TCA were reviewed from August 2017 to March 2020 at a tertiary care center. Outcomes included operative time, major (permanent recurrent laryngeal nerve (RLN) injury, permanent hypoparathyroidism, hematoma, conversion to open surgery), and minor complications. The TOETVA cohort was stratified into body mass index (BMI) classes of underweight/normal < 25 kg/m², overweight 25-29.9 kg/m², and obese ≥ 30 kg/m² for comparative analysis. Multivariable logistic regression analyses were performed for odds of cumulative complication.

RESULTS

Two hundred TOETVA and 333 TCA cases were included. There was no difference in incidence of major complications between the TOETVA and TCA cohorts (1.5% vs. 2.1%, p = 0.75). No difference was found in the rate of temporary RLN injury (4.5% vs. 2.1%, p = 0.124) or temporary hypoparathyroidism (18.2% vs. 12.5%, p = 0.163) for TOETVA and TCA, respectively. Surgical technique (TOETVA vs TCA) did not alter the odds of cumulative complication (OR 0.69 95% CI [0.26-1.85]) on logistic regression analysis. In the TOETVA cohort, higher BMI did not lead to a significantly greater odds of cumulative complication, 0.52 (95% CI [0.17-1.58]) and 1.69 (95% CI [0.74-3.88]) for the overweight and obese groups, respectively.

CONCLUSION

TOETVA can be performed in a North American patient population without a difference in odds of complication compared to TCA. Higher BMI is not associated with greater likelihood of complication with TOETVA.