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

New insights into the vitamin D/PTH axis in endocrine-driven metabolic bone diseases

BACKGROUND

Endocrine regulation of bone metabolisms is the focus of the "Skeletal Endocrinology" series of meetings.

AIMS

To report on the outcome of the discussion on the role of vitamin D/PTH axis in endocrine osteopathies held during the 10th Skeletal Endocrinology Meeting which took place in Stresa (Italy) in March 2023.

OUTCOMES

Vitamin D/PTH axis has relevant influence on several outcomes in the general population and in patients affected by endocrinopathies such as hypoparathyroidism and secreting pituitary adenomas.

CONCLUSIONS

Assessing the status of the vitamin D/PTH axis and using vitamin D and PTH as therapeutic agents is mandatory in several endocrine-related bone metabolic conditions.

Presentation of hypoparathyroidism in Italy: a nationwide register-based study

PURPOSE

We sought to assess the clinical presentation of hypoparathyroidism (HypoPT) in Italy.

METHODS

We performed a nationwide study retrieving data from the hospital discharge ICD-9 codes database of the Italian Health Ministry, from 2007 through 2017. The codes corresponding to diagnosis of cardiovascular disease, cancer, infection, renal failure, psychiatric disease, upper airway tract infection and pneumonia, seizures, nephrolithiasis, cognitive impairment, cerebral calcifications, skin disorders, fracture, and cataract were retrieved when associated with the diagnosis of HypoPT (252.1). We excluded codes corresponding to diagnoses of cancer of the neck region. In-hospital mortality rate was calculated. We retrieved the same data from an age- and sex-matched non-HypoPT control population.

RESULTS

Fourteen thousand five hundred seventy-nine hospitalizations for HypoPT and controls were analyzed. Hospitalization for cardiovascular disease, cancer, infection, renal failure, seizures, nephrolithiasis, cerebral calcifications (p < 0.0001), and cognitive impairment (p < 0.05) were more common in HypoPT compared to controls. Mean age of HypoPT with cardiovascular disease, cancer, and renal failure was younger compared to controls (p < 0.0001). The OR of hospitalization for cardiovascular disease, cancer, renal failure, seizures (OR 2, 40, 48  and 1.6, respectively), and nephrolithiasis (OR 1.6) were significant in HypoPT compared to non-HypoPT. The OR of hospitalization for infection and cognitive impairment were significant only in HypoPT women (OR 1.3 and 2.3, respectively). In-hospital mortality rate was lower in HypoPT vs controls (0.5% and 3.7%; p < 0.0001).

CONCLUSION

Hospitalizations for cardiovascular disease, cancer, and renal failure are more prevalent and occur at a younger age in HypoPT vs non-HypoPT. Hospitalizations for seizures and nephrolithiasis are frequent in HypoPT; those for infection and cognitive impairment are more common in HypoPT women.

Gallic acid pretreatment mitigates parathyroid ischemia-reperfusion injury through signaling pathway modulation

Thyroid surgery often results in ischemia-reperfusion injury (IRI) to the parathyroid glands, yet the mechanisms underlying this and how to ameliorate IRI remain incompletely explored. Our study identifies a polyphenolic herbal extract-gallic acid (GA)-with antioxidative properties against IRI. Through flow cytometry and CCK8 assays, we investigate the protective effects of GA pretreatment on a parathyroid IRI model and decode its potential mechanisms via RNA-seq and bioinformatics analysis. Results reveal increased apoptosis, pronounced G1 phase arrest, and significantly reduced cell proliferation in the hypoxia/reoxygenation group compared to the hypoxia group, which GA pretreatment mitigates. RNA-seq and bioinformatics analysis indicate GA's modulation of various signaling pathways, including IL-17, AMPK, MAPK, transient receptor potential channels, cAMP, and Rap1. In summary, GA pretreatment demonstrates potential in protecting parathyroid cells from IRI by influencing various genes and signaling pathways. These findings offer a promising therapeutic strategy for hypoparathyroidism treatment.

Cost-Effectiveness of Parathyroid Cryopreservation and Autotransplantation

Importance

Delayed autotransplantation of cryopreserved parathyroid tissue (DACP) is the only surgical treatment for permanent postoperative hypoparathyroidism. Studies suggest that only a small minority of cryopreserved samples are ultimately autotransplanted with highly variable outcomes. For these reasons, many have questioned the economic utility of the process, although, to the authors' knowledge, this has never been formally studied.

Objective

To report the clinical outcomes of parathyroid cryopreservation and DACP at a large academic institution and to determine the cost-effectiveness of this treatment.

Design, Setting, and Participants

An institutional review board-approved, retrospective review of patients at a single institution who underwent DACP over a 17-year period was conducted with a median follow-up of 48.2 months. A forward-looking cost-utility analysis was then performed to determine the economic utility of cryopreservation/DACP vs usual care (monitoring and supplementation). Patients who had parathyroid tissue in cryopreserved storage between August 2005 to September 2022 at a single-center, academic, quaternary care center were identified.

Exposure

Parathyroid cryopreservation and DACP.

Main Outcomes and Measures

Graft functionality, clinical outcomes, and cost utility using a willingness-to-pay threshold of $100 000 per quality-adjusted life-year (QALY).

Results

A total of 591 patients underwent cryopreservation. Of these, 10 patients (1.7%; mean [SD] age, 45.6 [17.9] years; 6 male [60%]) underwent DACP. A minority of autografts (2 [20%]) were subsequently fully functional, one-half (5 [50%]) were partially functional, and 3 (30%) were not functional. The cost-utility model estimated that at a large academic center over 10 years, the additional cost of 591 patients undergoing cryopreservation and 10 patients undergoing autotransplantation would be $618 791.64 (2022 dollars) and would add 8.75 QALYs, resulting in a cost per marginal QALY of $70 719.04, which is less than the common willingness-to-pay threshold of $100 000/QALY.

Conclusions and Relevance

The reimplantation rate of cryopreserved tissue was low (<2%), but when implanted, autografts were at least partially functional 70% of the time. In the first-ever, to the authors' knowledge, formal cost analysis for this treatment, results of the current model suggest that cryopreservation and autotransplantation were cost-effective compared with the usual care for hypoparathyroidism at a large, academic institution. It is recommended that each surgical center consider whether the economic and logistical commitments necessary for cryopreservation are worthwhile for their individual needs.

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.

[First experience of applying domestic video fluorescent equipment for visualization and blood flow evaluation of the parathyroid glands]

In recent years, predictive methods for assessing the preservation of the parathyroid glands have been actively implemented. The article describes the first experience of evaluating the blood supply of the parathyroid glands by quantitative determination of the indocyanine green (ICG) accumulation index in real time in 6 patients before and after a thyroidectomy with central neck lymph node dissection for papillary thyroid cancer. Intraoperative fluorescent angiography was performed by using domestic equipment with a fluorescent module, as well as by using a domestic medication of ICG. Intraoperative values of the ICG accumulation index were compared with the levels of ionized calcium and parathyroid hormone perioperatively. No clinical manifestations of hypocalcemia were detected in the postoperative period. The obtained results showed the informativeness of the numerical assessment of the intensity of ICG fluorescence. The evaluation of the distribution (accumulation) of ICG has prospects for practical application in thyroid surgery in the formation of tactics for preserving the parathyroid glands and predicting postoperative hypoparathyreosis.

Bone Marrow Adipose Tissue Is Increased in Postmenopausal Women With Postsurgical Hypoparathyroidism

CONTEXT

Suppression of bone turnover, greater trabecular volume, and normal-high normal all-site bone mineral density (BMD) are hallmarks of postsurgical hypoparathyroidism (HypoPT). Impairment in the trabecular microarchitecture with possible higher risk of vertebral fractures (VF) in women with postmenopausal HypoPT has also been described. Currently, no data on bone marrow adipose tissue (BMAT) are available in HypoPT.

OBJECTIVE

To assess BMAT by magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1H-MRS) in postmenopausal women with chronic postsurgical HypoPT.

METHODS

This cross-sectional pilot study, conducted at an ambulatory referral center, included 29 postmenopausal women (mean age 66 ± 8.4 years) with postsurgical HypoPT and 31 healthy postmenopausal women (mean age 63 ± 8.5). Lumbar spine MRI was performed and BMAT was measured by applying PRESS sequences on the L3 body. Lumbar spine, femoral neck, and total hip BMD were measured by dual x-ray absorptiometry (DXA); site-matched spine trabecular bone score (TBS) was calculated by TBS iNsight (Medimaps, Switzerland); VF assessment was performed with lateral thoracic and lumbar spine DXA.

RESULTS

Fat content (FC) and saturation level (SL%) were higher (P <.0001 and P <.001), while water content (W) was lower in HypoPT compared to controls (P <.0001). FC significantly correlated with years since menopause and body weight (P <.05) in HypoPT, while TBS negatively correlated with FC and SL% (P <.05) and positively with residual lipids (RL) and W (P <.05).

CONCLUSION

We demonstrate for the first time that BMAT is increased in postmenopausal women with postsurgical hypoparathyroidism and negatively associated with trabecular microarchitecture.

The Role of the Patient Partnership in Designing Research on Neuropsychiatric Issues in Hypoparathyroidism

Hypoparathyroidism is a rare endocrine disease that is associated with hypocalcemia and insufficient parathyroid hormone (PTH) levels. Neuropsychiatric complaints are common in hypoparathyroidism. Yet there is a large knowledge gap in our understanding of cognitive dysfunction in hypoparathyroidism and partnering with patients is essential for filling this hole. Input from hypoparathyroid patients is needed to define objective, performance-based cognitive impairments. Creating patient advisory boards that provide input for planning clinical trials would enable patient perspectives to be shared. This would ensure that meaningful, standardized neuropsychological instruments that prioritize patients' cognitive concerns are selected. Patient partnership is also needed to understand the wide inter-individual variability of cognitive symptoms in hypoparathyroidism, as well as mechanisms aside from calcium shifts that might explain cognitive symptoms, such as low PTH itself, alterations in brain structure, or other hypoparathyroidism-associated comorbidities. With new PTH replacement therapies on the horizon, patient input about studying how these therapies impact, and maybe even reverse, cognitive impairment will also be critical. Ultimately, the inclusion of patient partners in hypoparathyroidism research will advance the design of neuropsychiatric studies and generate key input for understanding how to reduce the burden of this disease.

Vitamin D in hypoparathyroidism: insight into pathophysiology and perspectives in clinical practice

Hypoparathyroidism (HypoPT) is a rare endocrine disorder characterized by the absence or insufficient parathyroid hormone production resulting in chronic hypocalcemia. Complications of HypoPT include perturbation of several target organs. The conventional treatment consists of the administration of active vitamin D, namely calcitriol. Regarding vitamin D status, few data are available, mostly in HypoPT subjects supplemented with parent vitamin D. In addition, perturbation of vitamin D metabolism has been poorly investigated, as well as the contribution of altered vitamin D status on the clinical expression of the disease. The most recent consensus on the management of chronic HypoPT suggests the baseline evaluation of serum 25-hydroxy-vitamin D [25(OH)D] and supplementation with parent vitamin D with the aim to achieve and maintain serum 25(OH)D levels in the range of 30-50 ng/mL. The rationale for using supplementation with parent vitamin D (either ergocalciferol or cholecalciferol) in HypoPT would be to provide sufficient 25(OH)D substrate to the residual 1-α-hydroxylase activity, thus ensuring its conversion to active vitamin D in renal and extra-renal tissues. More data from experimental and clinical studies are needed for better assessing how these mechanisms may significantly influence metabolic control in HypoPT and eventually skeletal and extra-skeletal manifestation of the disease. Finally, future data will clarify how the currently available parent vitamin D compounds (ergocalciferol, cholecalciferol, calcifediol) would perform in addressing these specific issues.

Management of Hypoparathyroidism

Hypoparathyroidism (HypoPT) is a rare disorder characterized by hypocalcemia in the presence of a low or inappropriately normal parathyroid hormone level. HypoPT is most commonly seen after neck surgery, which accounts for approximately 75% of cases, whereas approximately 25% have HypoPT due to nonsurgical causes. In both groups of patients, conventional therapy includes calcium and active vitamin D analogue therapy aiming to maintain serum calcium concentration in the low normal or just below the normal reference range and normalize serum phosphorus, magnesium concentrations, and urine calcium levels. The limitations of conventional therapy include wide fluctuations in serum calcium, high pill burden, poor quality of life, and renal complications. Parathyroid hormone (PTH) replacement therapy may improve the biochemical profile in those in whom conventional therapy proves unsatisfactory. Based on a systematic review and meta-analysis of the literature, the panel made a graded recommendation suggesting conventional therapy as first line therapy rather than administration of PTH (weak recommendation, low quality evidence). When conventional therapy is deemed unsatisfactory, the panel considers use of PTH. Because pregnancy and lactation are associated with changes in calcium homeostasis, close monitoring is required during these periods with appropriate adjustment of calcium and active vitamin D analogue therapy to ensure that serum calcium remains in the mid to low normal reference range in order to avoid maternal and fetal complications. Emerging therapies include molecules with prolonged PTH action as well as different mechanisms of action that may significantly enhance drug efficacy and safety. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Initial Assessment and Monitoring of Patients with Chronic Hypoparathyroidism: A Systematic Current Practice Survey

Chronic hypoparathyroidism (HypoPT) is associated with significant morbidity and impaired quality of life (QoL). The goals of management for chronic HypoPT include improvement in QoL and the prevention of both hypo- and hypercalcemia symptoms and long-term complications. Several groups have provided consensus statements and guidelines on the management of HypoPT; however, due to limited evidence, these recommendations have largely been based on literature reviews, expert opinion, and consensus statements. The objective of this study was to use a systematic approach to describe current practice for the initial assessment and follow-up of patients with chronic HypoPT. We developed a survey asking experts in the field to select the responses that best reflect their current practice. The survey found no differences in responses between nonsurgical and postsurgical patient assessment. For new patients, respondents usually performed an assessment of serum lab profile (calcium [either albumin-adjusted or ionized], magnesium, creatinine, phosphate, 25-hydroxyvitamin D), 24-hour urine (creatinine, calcium), and a renal ultrasound to evaluate for the presence of nephrocalcinosis or nephrolithiasis. For follow-up patients, most respondents perform blood tests and urine tests every 6 months or less frequently. The reported clinical practice patterns for monitoring for complications of chronic HypoPT vary considerably among respondents. Based on the responses in this systematic expert practice survey, we provide practice suggestions for initial assessment and follow-up of patients with chronic HypoPT. In addition, we highlight areas with significant variation in practice and identify important areas for future research. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Evaluation and Management of Hypoparathyroidism Summary Statement and Guidelines from the Second International Workshop

This clinical practice guideline addresses the prevention, diagnosis, and management of hypoparathyroidism (HypoPT) and provides evidence-based recommendations. The HypoPT task forces included four teams with a total of 50 international experts including representatives from the sponsoring societies. A methodologist (GG) and his team supported the taskforces and conducted the systematic reviews. A formal process following the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology and the systematic reviews provided the structure for seven of the guideline recommendations. The task force used a less structured approach based on narrative reviews for 20 non-GRADEd recommendations. Clinicians may consider postsurgical HypoPT permanent if it persists for >12 months after surgery. To predict which patients will not develop permanent postsurgical HypoPT, we recommend evaluating serum PTH within 12 to 24 hours post total thyroidectomy (strong recommendation, moderate quality evidence). PTH > 10 pg/mL (1.05 pmol/L) virtually excludes long-term HypoPT. In individuals with nonsurgical HypoPT, genetic testing may be helpful in the presence of a positive family history of nonsurgical HypoPT, in the presence of syndromic features, or in individuals younger than 40 years. HypoPT can be associated with complications, including nephrocalcinosis, nephrolithiasis, renal insufficiency, cataracts, seizures, cardiac arrhythmias, ischemic heart disease, depression, and an increased risk of infection. Minimizing complications of HypoPT requires careful evaluation and close monitoring of laboratory indices. In patients with chronic HypoPT, the panel suggests conventional therapy with calcium and active vitamin D metabolites as first-line therapy (weak recommendation, low-quality evidence). When conventional therapy is deemed unsatisfactory, the panel considers the use of PTH. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Hypoparathyroidism: update of guidelines from the 2022 International Task Force

The 2022 International Task Force guidelines for chronic hypoparathyroidism will be published within several months in the Journal of Bone and Mineral Research. These guidelines update the original guidelines published in 2016, and include new information from literature published since then. Chronic postsurgical hypoparathyroidism is now defined as lasting for at least 12 months after surgery, rather than 6 months. Chronic postsurgical hypoparathyroidism may be predicted by serum PTH <10 pg/mL in the first 12-24 hours after surgery. The most common symptoms and complications of chronic hypoparathyroidism based on the literature are summarized in detail. How to monitor and manage patients with hypoparathyroidism is described in detail where recommendations can be given. These guidelines are intended to frame the diagnosis and care of patients with chronic hypoparathyroidism for at least the next five years.