A territory-wide assessment of the incidence of persistent hypoparathyroidism after elective thyroid surgery and its impact on new fracture risk over time

Risk factors of transient and permanent hypoparathyroidism after thyroidectomy: a systematic review and meta-analysis

BACKGROUND

Postoperative hypoparathyroidism (hypoPT) is a common complication following thyroid surgery. However, current research findings on the risk factors for post-thyroid surgery hypoPT are not entirely consistent, and the same risk factors may have different impacts on transient and permanent hypoPT. Therefore, there is a need for a comprehensive study to summarize and explore the risk factors for both transient and permanent hypoPT after thyroid surgery.

MATERIALS AND METHODS

Two databases (PubMed and Embase) were searched from inception to 2024. The Newcastle-Ottawa Scale was used to rate study quality. Pooled odds ratios were used to calculate the relationship of each risk factor with transient and permanent hypoPT. Subgroup analyses were conducted for hypoPT with different definition-time (6 or 12 months). Publication bias was assessed using Begg's test and Egger's test.

RESULTS

A total of 19 risk factors from the 93 studies were included in the analysis. Among them, sex and parathyroid autotransplantation were the most frequently reported risk factors. Meta-analysis demonstrated that sex (female vs. male), cN stage, central neck dissection, lateral neck dissection, extent of central neck dissection (bilateral vs. unilateral), surgery [total thyroidectomy (TT) vs. lobectomy], surgery type (TT vs. sub-TT), incidental parathyroidectomy, and pathology (cancer vs. benign) were significantly associated with transient and permanent hypoPT. Preoperative calcium and parathyroid autotransplantation were only identified as risk factors for transient hypoPT, while preoperative PTH was a protective factor. Additionally, node metastasis and parathyroid in specimen were associated with permanent hypoPT.

CONCLUSION

The highest risk of hypoPT occurs in female thyroid cancer patients with lymph node metastasis undergoing TT combined with neck dissection. The key to preventing postoperative hypoPT lies in the selection of surgical approach and intraoperative protection.

The Two-Year Results of Using Radiofrequency Ablation as a Novel Treatment for Persistent or Relapsed Graves' Disease: A Prospective Study

Objectives: Graves' disease (GD) is the most common cause of hyperthyroidism. Antithyroid drugs (ATDs) are the first-line treatment, but when discontinued, >50% of patients experience relapses. Conventional definitive treatment options include surgery and radioiodine therapy (RAI), each with its own disadvantages. Radiofrequency ablation (RFA) achieved promising short-term remission rates in a previous pilot study. The current study reports our experience of using RFA to treat relapsed GD in the largest cohort of patients with a longer follow-up period. Methods: This single-arm prospective study recruited consecutive patients aged ≥18 with persistent/relapsed GD requiring ATD from two tertiary endocrine surgery centers. Those with compressive goiter, suspected thyroid malignancy, moderate-to-severe Graves' ophthalmopathy, preference for surgery/RAI, or pregnancy were excluded. Eligible patients received ultrasound-guided RFA to the entire bulk of the thyroid gland. ATDs were discontinued afterward, and thyroid function tests were monitored bimonthly. The primary outcome was the disease remission rate at 24 months follow-up after single-session RFA, defined as being biochemically euthyroid or hypothyroid without ATD. Secondary outcomes were complication rates. Results: Of the 100 patients considered, 30 (30.0%) patients were eligible and received RFA. Most were female patients (93.3%). The median total thyroid volume was 23 mL (15.9-34.5). All completed 24 months follow-up. After single-session RFA, disease remission rates were 60.0% at 12 months and 56.7% at 24 months. Among the 13 patients with relapse after RFA, 9 (69%) required a lower ATD dose than before RFA; 2 received surgery without complications. Total thyroid volume was the only significant factor associated with relapse after RFA (odds ratio 1.054, confidence interval 1.012-1.099, p = 0.012). At 24 months, RFA led to disease remission in 100% of the 9 patients with a total thyroid volume <20 mL and 35% of patients with a total thyroid volume ≥20 mL (p = 0.007). There was no vocal cord palsy, skin burn, hematoma, or thyroid storm after RFA. Conclusions: In a highly selected group of patients with relapsed GD and predominantly small thyroid glands, single-session RFA may achieve disease remission. Smaller total thyroid volume may be a favorable factor associated with disease remission after RFA. The results of this study need to be confirmed with a long-term clinical trial. Clinical Trial Registration: This study is registered at www.clinicaltrial.gov with identifier NCT06418919.

Long-term kidney outcomes in patients with permanent hypoparathyroidism after total thyroidectomy for benign disease: A population-based study

BACKGROUND

Permanent hypoparathyroidism is a significant complication after total thyroidectomy. This study aimed to evaluate the long-term impact of postoperative permanent hypoparathyroidism on kidney outcomes.

METHODS

Data of patients undergoing total thyroidectomy from 1999 to 2014 were retrieved. The estimated glomerular filtration rate was determined from serum creatinine results. Permanent hypoparathyroidism was defined as requiring oral calcium and vitamin D supplements postoperatively for at least 6 months. The primary outcome was a sustained decline in the estimated glomerular filtration rate from baseline by ≥50%. Secondary outcomes were end-stage kidney disease (a composite of sustained estimated glomerular filtration rate <15 mL/min/1.73 m2, need for dialysis, and kidney transplantation) and rate of estimated glomerular filtration rate decline. Patients with and without permanent hypoparathyroidism were compared. Multivariable Cox regression analysis was performed to identify independent risk factors for sustained estimated glomerular filtration rate decline by ≥50%.

RESULTS

In total, 3,245 patients were eligible for analysis; 418 patients (12.9%) had permanent hypoparathyroidism. Upon median follow-up of 11.6 years, more patients with permanent hypoparathyroidism had a sustained decline in estimated glomerular filtration rate from baseline by ≥50% compared to those without (15.6% vs 6.9%, P < .001). Similar findings were obtained on Kaplan-Meier analysis (P < .001). Permanent hypoparathyroidism was an independent risk factor for sustained estimated glomerular filtration rate decline by ≥50% (adjusted hazard ratio 2.77, P < .001). Other risk factors included age, preoperative estimated glomerular filtration rate <60 mL/min/1.73m2, and diabetes mellitus. Patients with permanent hypoparathyroidism had a more rapid estimated glomerular filtration rate decline (-1.60 vs -0.70 mL/min/1.73 m2/year, difference -0.91 mL/min/1.73m2/year, P < .001).

CONCLUSION

Patients with postsurgical permanent hypoparathyroidism were at greater risk of renal impairment. Further research is warranted to improve the identification and preservation of parathyroid glands during thyroidectomy to minimize patient morbidity.

Incident comorbidities in patients with chronic hypoparathyroidism after thyroidectomy: a multicenter nationwide study

Purpose

Population-based and registry studies have shown that chronic hypoparathyroidism is accompanied by long-term complications. We aimed to evaluate the risk of incident comorbidity among patients with chronic postsurgical hypoparathyroidism in real-life clinical practice in Spain.

Methods

We performed a multicenter, retrospective cohort study including patients with chronic postsurgical hypoparathyroidism lasting ≥3 years with at least a follow-up visit between January 1, 2022 and September 15, 2023 (group H). The prevalence and incidence of chronic complications including chronic kidney disease, nephrolithiasis/nephrocalcinosis, hypertension, dyslipidemia, diabetes, cardiovascular disease, central nervous system disease, mental health disorders, eye disorders, bone mineral density alterations, fracture and cancer were evaluated. Patient data were compared with a group of patients who did not develop hypoparathyroidism, matched by gender, age, and follow-up time after thyroidectomy (group NH).

Results

We included 337 patients in group H (median [IQR] age, 45 [36-56] years; median time of follow-up, 8.9 [6.0-13.0] years; women, 84.3%) and 669 in group NH (median age, 47 [37-55] years; median time of follow-up, 8.0 [5.3-12.0] years; women, 84.9%). No significant differences were found in the prevalence of comorbidities at the time of thyroidectomy between both groups. In multivariable adjusted analysis, patients with chronic hypoparathyroidism had significantly higher risk of incident chronic kidney disease (OR, 3.45; 95% CI, 1.72-6.91; P<0.001), nephrolithiasis (OR, 3.34; 95% CI, 1.55-7.22; P=0.002), and cardiovascular disease (OR, 2.03; 95% CI, 1.14-3.60; P=0.016), compared with patients without hypoparathyroidism. On the contrary, the risk of fracture was decreased in patients with hypoparathyroidism (OR, 0.09; 95% CI, 0.01-0.70; P=0.021).

Conclusion

This study demonstrates that, in the clinical practice of Spanish endocrinologists, a significant increase in the risk of chronic kidney disease, nephrolithiasis and cardiovascular disease, as well as a reduction in the risk of fractures is detected. These results are of interest for the development of new clinical guidelines and monitoring protocols for patients with hypoparathyroidism.

Efficacy of single-session radiofrequency ablation (RFA) in rendering euthyroidism for persistent/relapsed Graves' disease, a pilot study

OBJECTIVES

Graves' disease (GD) is the most common cause of hyperthyroidism. Antithyroid drug (ATD) is often the first-line treatment but  > 50% patients suffer a relapse when ATD is discontinued. Surgery or radioiodine remains the current options of definitive treatment in these patients. This pilot study examined the short-term efficacy of single-session thyroid radiofrequency ablation (RFA) as a novel definitive treatment for persistent/relapsed GD.

METHODS

Consecutive patients with persistent/relapsed GD requiring ATD were considered. Those with a clear surgical indication, either thyroid lobe volume  ≥ 20 mL; those who were pregnant or lactating; and those who had any severe medical conditions that would pose extra treatment risks were excluded. Eligible patients received ultrasound-guided RFA of the entire bulk of thyroid gland. Thyroid function tests were monitored bi-monthly. The primary outcome was disease remission rate, defined as a state of biochemical euthyroidism or hypothyroidism without ATD. Secondary outcomes were complication rates.

RESULTS

Of the 68 patients considered, 15 (22.1%) patients were eligible. Most were females (93.3%). The median age was 37 (IQR 31-48) years old. The disease remission rates were 79.0% at 6 months and 73.3% at 12 months. Among the 4 patients who relapsed after RFA, three required less ATD dose than before RFA. RFA was well-tolerated in the ambulatory setting. There were no vocal cord palsy, skin burn, hematoma, or thyroid storm after RFA.

CONCLUSIONS

In well-selected patients, single-session RFA of the thyroid gland may be a potential treatment for patients with persistent/relapsed GD. It is a safe and well-tolerated ambulatory procedure.

KEY POINTS

• Radiofrequency ablation of the thyroid gland is an efficacious treatment for persistent/relapsed Graves' disease in well-selected patients. • Radiofrequency ablation of the thyroid gland for the treatment of persistent/relapsed Graves' disease is a safe and well-tolerated ambulatory procedure. • Radiofrequency ablation of the thyroid gland may be a potential alternative treatment for well-selected patients with persistent/relapsed GD who do not wish to undergo either thyroidectomy or radioactive iodine or continue antithyroid drugs.

Risk of Permanent Hypoparathyroidism Requiring Calcitriol Therapy in a Population-Based Cohort of Adults Older Than 65 Undergoing Total Thyroidectomy for Graves' Disease

Objective: Total thyroidectomy for Graves' disease (GD) is associated with rapid treatment of hyperthyroidism and low recurrence rates. However, it carries the risk of surgical complications including permanent hypoparathyroidism, which contributes to long-term impaired quality of life. The objective of this study was to determine the incidence of permanent hypoparathyroidism requiring calcitriol therapy among a population-based cohort of older adults undergoing total thyroidectomy for GD in the United States. Methods: We performed a population-based cohort study using 100% Medicare claims from beneficiaries older than 65 years with GD who underwent total thyroidectomy from 2007 to 2017. We required continuous enrollment in Medicare Parts A, B, and D for 12 months before and after surgery to ensure access to comprehensive claims data. Patients were excluded if they had a preoperative diagnosis of thyroid cancer or were on long-term preoperative calcitriol. Our primary outcome was permanent hypoparathyroidism, which was identified based on persistent use of calcitriol between 6 and 12 months following thyroidectomy. We used multivariable logistic regression to identify characteristics associated with permanent hypoparathyroidism, including patient age, sex, race/ethnicity, neighborhood disadvantage, Charlson-Deyo Comorbidity Index, urban or rural residence, and frailty. Results: We identified 4650 patients who underwent total thyroidectomy for GD during the study period and met the inclusion criteria (mean age = 72.8 years [standard deviation = 5.5], 86% female, and 79% white). Among this surgical cohort, 104 (2.2% [95% confidence interval, CI = 1.8-2.7%]) patients developed permanent hypoparathyroidism requiring calcitriol therapy. Patients who developed permanent hypoparathyroidism were on average older (mean age 74.1 vs. 72.8 years) than those who did not develop permanent hypoparathyroidism (p = 0.04). On multivariable regression, older age was the only patient characteristic associated with permanent hypoparathyroidism (odds ratio age ≥76 years = 1.68 [CI = 1.13-2.51] compared with age 66-75 years). Conclusions: The risk of permanent hypoparathyroidism requiring calcitriol therapy among this national, U.S. population-based cohort of older adults with GD treated with total thyroidectomy was low, even when considering operations performed by a heterogeneous group of surgeons. These findings suggest that the risk of hypoparathyroidism should not be a deterrent to operative management for GD in older adults who are appropriate surgical candidates.

Complications, Symptoms, Presurgical Predictors in Patients With Chronic Hypoparathyroidism: A Systematic Review

The complications and symptoms of hypoparathyroidism remain incompletely defined. Measuring serum parathyroid hormone (PTH) and calcium levels early after total thyroidectomy may predict the development of chronic hypoparathyroidism. The study aimed (i) to identify symptoms and complications associated with chronic hypoparathyroidism and determine the prevalence of those symptoms and complications (Part I), and (ii) to examine the utility of early postoperative measurements of PTH and calcium in predicting chronic hypoparathyroidism (Part II). We searched Medline, Medline In-Process, EMBASE, and Cochrane CENTRAL to identify complications and symptoms associated with chronic hypoparathyroidism. We used two predefined criteria (at least three studies reported the complication and symptom and had statistically significantly greater pooled relative estimates). To estimate prevalence, we used the median and interquartile range (IQR) of the studies reporting complications and symptoms. For testing the predictive values of early postoperative measurements of PTH and calcium, we used a bivariate model to perform diagnostic test meta-analysis. In Part I, the 93 eligible studies enrolled a total of 18,973 patients and reported on 170 complications and symptoms. We identified nine most common complications or symptoms probably associated with chronic hypoparathyroidism. The complications or symptoms and the prevalence are as follows: nephrocalcinosis/nephrolithiasis (median prevalence among all studies 15%), renal insufficiency (12%), cataract (17%), seizures (11%), arrhythmia (7%), ischemic heart disease (7%), depression (9%), infection (11%), and all-cause mortality (6%). In Part II, 18 studies with 4325 patients proved eligible. For PTH measurement, regarding the posttest probability, PTH values above 10 pg/mL 12-24 hours postsurgery virtually exclude chronic hypoparathyroidism irrespective of pretest probability (100%). When PTH values are below 10 pg/mL, posttest probabilities range from 3% to 64%. Nine complications and symptoms are probably associated with chronic hypoparathyroidism. A PTH value above a threshold of 10 pg/mL 12-24 hours after total thyroidectomy is a strong predictor that the patients will not develop chronic hypoparathyroidism. Patients with PTH values below the threshold need careful monitoring as some will develop chronic hypoparathyroidism. © 2022 American Society for Bone and Mineral Research (ASBMR).

Actual prevalence of hypoparathyroidism after total thyroidectomy: a health insurance claims-database study

PURPOSE

Persistent hypoparathyroidism (hypoPT) is a major complication of total thyroidectomy. Nonetheless, previous reports may have underestimated the prevalence of hypoPT due to patient selection bias. We aimed to estimate the actual prevalence of persistent hypoPT after total thyroidectomy and to find predictive factors for postoperative hypoPT.

METHODS

This study retrospectively reviewed data from a health insurance claims-based database provided by the Japan Medical Data Center Co., Ltd. From 2009 to 2019, 2388 patients who underwent total thyroidectomy were identified using the medical procedure codes. Persistent hypoPT was defined as the prescription of active vitamin D supplements for >1 year postoperatively and the assignment of hypoPT codes. The prevalence of persistent hypoPT was estimated at two different levels: minimum and maximum estimations with or without postoperative osteoporosis and/or renal failure codes. Correlates for persistent hypoPT were investigated among several demographic and clinical variables.

RESULTS

Of the 2388 patients, 1752 (73.4%) were women with a mean age of 45 years. The types of diseases were: benign thyroid disease (n = 235), malignant thyroid tumors (n = 1570), Graves ' disease (n = 558), and malignancy combined with Graves' disease (n = 25). The minimum and the maximum estimation of the prevalence of persistent hypoPT were 15.0 and 20.3%, respectively. Multivariate logistic regression analysis showed that the malignant tumor (odds ratio, 1.8) independently correlated with persistent hypoPT.

CONCLUSIONS

The prevalence of persistent hypoPT after total thyroidectomy estimated by the claims-based database was higher than previously recognized. Comprehensive attempts to preserve parathyroid function, especially in malignant diseases, are essential.

Predictors of Anxiety and Depression in Differentiated Thyroid Cancer Survivors: Results of a Cross-Sectional Study

Background: Despite an excellent survival rate, impairments are recognized in the quality of life and emotional well-being of differentiated thyroid cancer (DTC) survivors. Predictors for anxiety and depression in DTC patients are not well characterized. Objective: To identify predictors for anxiety and depression in DTC survivors. Methods: In this cross-sectional study, all DTC survivors presenting for follow-up between 2014 and 2019 in a tertiary referral hospital were asked to complete the "Hospital Anxiety and Depression Scale" (HADS). Depression (HADS-D) and anxiety (HADS-A) subscores were dichotomized for analysis. Univariate and multivariable logistic regression analyses were performed to identify predictors of anxiety and depression. Inverse probability weighting was applied to correct for bias due to nonresponse. Results: Six hundred forty patients meeting study inclusion criteria completed the HADS questionnaire (73% female, mean age 50 years). Of these, 37.6% and 15.7% of patients demonstrated HADS-A and HADS-D scores ≥8. Female sex, elevated body mass index (BMI), permanent recurrent laryngeal nerve damage (RLND), permanent hypoparathyroidism (PH), comorbidities classified in chapter XIX of the International Classification of Diseases, 10th Revision (ICD-10; external causes of morbidity and mortality), and comorbidities in chapter XXI of ICD-10 (factors influencing health status and contact with health services) were independent predictors for elevated anxiety scores with adjusted odds ratios of 1.9 ([CI 1.2-3.2], p < 0.01), 1.0 ([CI 1.0-1.1], p = 0.02), 2.6 ([CI 1.0-6.3], p = 0.04), 2.0 ([CI 1.1-3.5], p = 0.02), 5.5 ([CI 1.0-29.6], p < 0.05), and 1.7 ([CI 1.1-2.6], p = 0.03). PH, elevated anti-Tg titer, comorbidities of the digestive system (chapter XI of ICD-10), and comorbidities of the genitourinary system (chapter XIV of ICD-10) were independent predictors for depression with adjusted odds ratios of 2.2 ([CI 1.2-4.2], p = 0.01), 1.0 ([CI 1.0-1.0], p = 0.04), 3.0 ([CI 1.5-6.1], p < 0.01), and 2.4 ([CI 1.0-5.7], p = 0.04). Conclusions: Female sex, elevated BMI, RLND, PH, and comorbidities classified in chapter XIX and chapter XXI of ICD-10 are predictors for anxiety in DTC patients. PH, elevated anti-Tg titer, comorbidities of the digestive system, and comorbidities of the genitourinary system are predictors for depression in DTC patients. Physicians involved in the follow-up of DTC patients should devote particular attention to the emotional well-being in DTC patients with PH or permanent RLND.

Safety of Inactivated and mRNA COVID-19 Vaccination Among Patients Treated for Hypothyroidism: A Population-Based Cohort Study

Background: Thyroiditis and Graves' disease have been reported after coronavirus disease 2019 (COVID-19) vaccination. We evaluated the risks of adverse events after COVID-19 vaccination among patients treated for hypothyroidism. Methods: In this retrospective population-based cohort study of Hong Kong Hospital Authority electronic health records with the Department of Health vaccination records linkage, levothyroxine (LT4) users were categorized into unvaccinated, vaccinated with BNT162b2 (mRNA vaccine), or CoronaVac (inactivated vaccine) between February 23, 2021, and September 9, 2021. Study outcomes were dosage reduction or escalation in LT4, emergency department (ED) visit, unscheduled hospitalization, adverse events of special interest (AESI) according to the World Health Organization's Global Advisory Committee on Vaccine Safety, and all-cause mortality. Inverse probability of treatment weighting for propensity score was applied to balance baseline patient characteristics among the three groups. Hazard ratios (HR) were estimated using Cox regression models. Patients were observed from the index date until the occurrence of study outcome, death, or censored on September 30, 2021, whichever came first. Results: In total, 47,086 LT4 users were identified (BNT162b2: n = 12,310; CoronaVac: n = 11,353; and unvaccinated: n = 23,423). COVID-19 vaccination was not associated with increased risks of LT4 dosage reduction (BNT162b2: HR = 0.971 [confidence interval; CI 0.892-1.058]; CoronaVac: HR = 0.968 [CI 0.904-1.037]) or escalation (BNT162b2: HR = 0.779 [CI 0.519-1.169]; CoronaVac: HR = 0.715 [CI 0.481-1.062]). Besides, COVID-19 vaccination was not associated with a higher risk of ED visits (BNT162b2: HR = 0.944 [CI 0.700-1.273]; CoronaVac: HR = 0.851 [CI 0.647-1.120]) or unscheduled hospitalization (BNT162b2: HR = 0.905 [CI 0.539-1.520]; CoronaVac: HR = 0.735 [CI 0.448-1.207]). There were two (0.016%) deaths and six (0.062%) AESI recorded for BNT162b2 recipients, and one (0.009%) and three (0.035%) for CoronaVac recipients, respectively. Conclusions: BNT162b2 or CoronaVac vaccination is not associated with unstable thyroid status or an increased risk of adverse outcomes among patients treated for hypothyroidism in general. These reassuring data should encourage them to get vaccinated against COVID-19 for protection from potentially worse COVID-19-related outcomes.

Thyroidectomy for Cancer: The Surgeon and the Parathyroid Glands Sparing

BACKGROUND

The diagnosis of thyroid cancer is continuously increasing and consequently the amount of thyroidectomy. Notwithstanding the actual surgical skill, postoperative hypoparathyroidism still represents its most frequent complication. The aims of the present study are to analyze the rate of postoperative hypoparathyroidism after thyroidectomy, performed for cancer by a single first operator, without any technological aid, and to compare the data to those obtained adopting the most recent technological adjuncts developed to reduce the postoperative hypoparathyroidism.

METHODS

During the period 1997-2020 at the Endocrine Surgery Unit of the Department of Clinical and Experimental Medicine of the University of Florence, 1648 consecutive extracapsular thyroidectomies for cancer (401 with central compartment node dissection) were performed. The percentage of hypoparathyroidism, temporary or permanent, was recorded both in the first period (Group A) and in the second, most recent period (Group B). Total thyroidectomies were compared either with those with central compartment dissection and lobectomies. Minimally invasive procedures (MIT, MIVAT, some transoral) were also compared with conventional. Fisher's exact and Chi-square tests were used for comparison of categorical variables. p < 0.01 was considered statistically significant. Furthermore, a literature research from PubMed^® has been performed, considering the most available tools to better identify parathyroid glands during thyroidectomy, in order to reduce the postoperative hypoparathyroidism. We grouped and analyzed them by technological affinity.

RESULTS

On the 1648 thyroidectomies enrolled for the study, the histotype was differentiated in 93.93 % of cases, medullary in 4% and poorly differentiated in the remaining 2.06%. Total extracapsular thyroidectomy and lobectomy were performed respectively in 95.45% and 4.55%. We recorded a total of 318 (19.29%) cases of hypocalcemia, with permanent hypoparathyroidism in 11 (0.66%). In regard to the literature, four categories of tools to facilitate the identification of the parathyroids were identified: (a) vital dye; (b) optical devices; (c) autofluorescence of parathyroids; and (d) autofluorescence enhanced by contrast media. Postoperative hypoparathyroidism had a variable range in the different groups.

CONCLUSIONS

Our data confirm that the incidence of post-surgical hypoparathyroidism is extremely low in the high volume centers. Its potential reduction adopting technological adjuncts is difficult to estimate, and their cost, together with complexity of application, do not allow immediate routine use. The trend towards increasingly unilateral surgery in thyroid carcinoma, as confirmed by our results in case of lobectomy, is expected to really contribute to a further reduction of postsurgical hypoparathyroidism.