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

Hypoparathyroidism: diagnosis, management and emerging therapies

Hypoparathyroidism is characterized by inadequate parathyroid hormone (PTH) secretion or action and results in hypocalcaemia, and can lead to hyperphosphataemia and hypercalciuria. Most cases of hypoparathyroidism occur as a complication of surgery, with the remainder due to causes including autoimmune disease, genetic causes, infiltrative diseases, mineral deposition or due to abnormalities in serum levels of magnesium. Hypoparathyroidism can cause multisystem disease, with long-term complications resulting from ectopic calcification as well as renal complications with nephrocalcinosis, nephrolithiasis and renal impairment in addition to respiratory, cardiac or neurological manifestations. Conventional therapy consists of oral calcium salts and active vitamin D but it has limitations, including fluctuations in serum levels of calcium and a high pill burden, and can increase the risk of long-term complications. By contrast, PTH replacement therapy can effectively achieve normal serum levels of calcium, and lower serum levels of phosphate. The long-acting PTH analogue, palopegteriparatide, has been shown to normalize urine levels of calcium. In addition, PTH replacement therapy reduces the pill burden. Palopegteriparatide is also associated with improved quality of life in comparison to conventional therapy. This Review summarizes current recommendations regarding the pathophysiology, evaluation and management of hypoparathyroidism and also references the 2022 international hypoparathyroidism guidelines. Palopegteriparatide has now been approved as PTH replacement therapy for hypoparathyroidism. Emerging therapies will also be presented in this Review.

Correlation Between Serum 1,25(OH)2D3, Serum Phosphorus, and Parathyroid Hormone and Parathyroid Function After Central Lymph Node Dissection in Patients with Papillary Thyroid Carcinoma

This work was to demonstrate the relationship between serum 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), serum phosphorus (SP), and parathyroid hormone (PTH) and parathyroid function after central lymph node dissection (CLND) in patients with papillary thyroid carcinoma (PTC). 200 PTC patients after CLND were included, who were rolled into a control group (CG) (n = 89 cases without hypoparathyroidism) and an observation group (OG) (n = 111 cases with complicated hypoparathyroidism). The 1,25(OH)2D3, SP, and PTH levels were detected, and the diagnostic effect of these indicators was assessed. The serum PTH levels of patients in CG after surgery were normal relative to those before surgery, while the serum PTH of patients in OG was relatively lower. 1,25(OH)2D3 concentration of patients in OG was also inferior to CG, while the SP level was superior (P < 0.05). Hypoparathyroidism was positively correlated with serum PTH (r = 0.382) and 1,25(OH)2D3 (r = 0.321) and negatively correlated with SP (r =  - 0.211). The area under the curve (AUC) (0.893), sensitivity (90.83%), and specificity (94.77%) of the joint diagnosis of 1,25(OH)2D3 + SP + PTH were greatly superior to those of the single diagnosis and the pairwise diagnosis with the three indicators (P < 0.05). Hypoparathyroidism in patients with PTC after CLND surgery was positively correlated with 1,25(OH)2D3 and PTH and negatively correlated with SP concentration. In addition, the combination diagnosis of 1,25(OH)2D3, PTH, and SP worked well.

Management of autosomal dominant hypocalcemia type 1: Literature review and clinical practice recommendations

PURPOSE

Autosomal Dominant Hypocalcemia type 1 (ADH1), caused by gain-of-function variants in the calcium-sensing receptor (CASR), is characterized by a variable degree of hypocalcemia and hypercalciuria with inappropriately low PTH. The clinical spectrum is broad, ranging from being asymptomatic to presenting with severe clinical features of hypocalcemia and end-organ damage such as nephrolithiasis and intracerebral calcifications. Although the underlying pathophysiology is different, ADH1 patients are often managed as patients with 'classical' primary hypoparathyroidism, possibly leading to (exacerbation of) hypercalciuria. New treatments such as PTH analogues and calcilytics directly targeting the CASR are in the pipeline. Specific clinical guidance for treatment and monitoring of ADH1 patients is lacking. The purpose of this study is to provide a literature review on management of ADH1, including new therapies, and to formulate practice recommendations.

METHODS

We searched for articles and ongoing clinical trials regarding management of ADH1.

RESULTS

Forty articles were included. First we review the conventional treatment of ADH1, focusing on active vitamin D, calcium supplements, thiazide diuretics, phosphorus binders and dietary recommendations. In a second part we give an overview of studies with emerging treatments in ADH1: PTH analogues (PTH1-34, rhPTH1-84, TransCon PTH and others) and calcilytics (preclinical studies and clinical trials). In a third part we discuss literature findings regarding monitoring of ADH1 patients. Finally, we formulate clinical practice recommendations.

CONCLUSION

We provide an overview of conventional and new treatments for ADH1 patients. Based on these data, we propose practical recommendations to assist clinicians in the management of ADH1 patients.

Methodology for the international working group clinical practice guidelines on X-linked hypophosphatemia in children and adults

The guideline panel, comprising international experts in X-linked hypophosphatemia (XLH), patient partners from the XLH patient population, and guideline methodologists, held 18 teleconferences between January 2023 and July 2024 to develop comprehensive guidelines for the diagnosis and management of XLH in children and adults. For a subset of our questions, we utilized the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology, assessed the certainty of evidence and formulated GRADEd recommendations. For these questions, the panelists and methodologists collaboratively framed PICO (Population, Intervention, Control, and Outcomes) questions and conducted four systematic reviews assessing the impact of medical therapy-using either burosumab or phosphate and active vitamin D-on patient-important outcomes in the XLH population as well as the impact of medical intervention compared to no treatment. We assessed the risk of bias and transparently generated summary of findings tables using MAGICApp. The panel developed three GRADEd treatment recommendations for adults and two for children. Each GRADEd recommendation was linked to an underlying body of evidence, reflecting judgments on the certainty of evidence, recommendation strength, values, preferences, and considerations of costs, feasibility, acceptability, and equity. Due to the paucity of evidence, the panel developed very low-quality GRADEd recommendations on monitoring patients with XLH based on an expert clinical practice survey. Using a rigorous narrative literature review, the panel developed non-GRADEd recommendations including guidance for pregnant women, patients with dental complications, and other areas where evidence is limited. This article summarizes the methodology utilized for the development of both GRADEd and non-GRADEd recommendations for patients with XLH.

PTH Substitution Therapy for Chronic Hypoparathyroidism: PTH 1-84 and Palopegteriparatide

PURPOSE OF REVIEW

to describe and compare the efficacy and safety of the main PTH treatments, namely PTH(1-84) and palopegteriparatide, for the management of hypoparathyroidism.

RECENT FINDINGS

neither PTH (1-84) nor PTH(1-34) have been shown a clear and consistent favorable impact on the 24 h urinary calcium excretion normalization, while the positive effect on quality of life is still debated. Recently, the Food & Drug Administration and the European Medicines Agency approved palopegteriparatide as the first true replacement therapy for hypoPT management. Palopegteriparatide is a prodrug of PTH(1-34), administered once daily, and designed to provide continuous exposure to released PTH over a 24-h dosing period. According to phase II and phase III studies, palopegteriparatide seems to fill the gaps identified in existing therapies for hypoPT. Palopegteriparatide is the first real replacement therapy for the management of hypoparathyroidism and seems to fill the gaps identified in existing therapies for hypoPT.

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.

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.

Case Report: Calcium sensing receptor gene gain of function mutations: a case series and report of 2 novel mutations

Autosomal dominant hypocalcemia (ADH1) is a genetic disorder characterized by low serum calcium and low or inappropriately normal levels of parathyroid hormone. The disease is caused by a heterozygous activating mutation of the calcium-sensing receptor (CaSR) gene, encoding a G-Protein-coupled cell membrane sensor of extracellular calcium concentration mainly expressed by parathyroid glands, renal tubules, and the brain. ADH1 has been linked to 113 unique germline mutations, of which nearly 96% are missense mutations. There is often a lack of a clear genotype/phenotype correlation in the reported literature. Here, we described a case series of 6 unrelated ADH1 probands, each one bearing a gain-of-function CaSR mutation, and two children of one of these cases, matching our identified mutations to the same ones previously reported in the literature, and comparing the clinical and biochemical characteristics, as well as the complication profile. As a result of these genetic and clinical comparisons, we propose that a genotype/phenotype correlation may exist because our cases showed similar presentation, characteristics, and severity, with respect to published cases with the same or similar mutations. We also contend that the severity of the presentation is highly influenced by the specific CaSR variant. These findings, however, require further evaluation and assessment with a systematic review.

Continuous subcutaneous rhPTH infusion for managing difficult chronic hypoparathyroidism. A systematic review

PURPOSE

Standard treatment for chronic hypoparathyroidism is represented by long-life per os supplementation of calcium and vitamin D. Since 90s, exogenous PTH is also available, but a not negligible number of patients experience a poor control. Starting from the experience with pumps in diabetes, it has been hypothesized that the infusion of PTH through pump might result in a better disease control. The aim of this systematic review is to summarize the published data about continuous subcutaneous PTH infusion in chronic hypoPTH patients and achieve conclusions for clinical practice.

METHODS

A comprehensive computer literature search of the PubMed/MEDLINE, Embase, and Scopus databases was conducted by two authors independently (last search on November 30, 2022). All findings were summarized and critically discussed.

RESULTS

We included 14 of the 103 retrieved articles, 2 RCTs, 8 case reports, and 4 case series, published between 2008 and 2022. Of the total 40 patients, 17 were adults, and 23 pediatric. The etiology was postsurgical in 50% of cases and genetic in the other 50%. All had a failure of standard care and a rapid improvement of clinical and biochemical parameters on PTH pump therapy, without severe adverse events.

CONCLUSIONS

Based on literature, pump PTH infusion may represent an effective, safe, and feasible option for patients with chronic hypoparathyroidism refractory to standard therapy. From a clinical perspective, careful patient selection, a skilled healthcare team, the assessment of the local setting and the collaboration with pump suppliers are essential.

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).

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.

Methodology for the Guidelines on Evaluation and Management of Hypoparathyroidism and Primary Hyperparathyroidism

To develop guidelines for hypoparathyroidism and primary hyperparathyroidism, the panel assembled a panel of experts in parathyroid disorders, general endocrinologists, representatives of the Hypoparathyroidism Association, and systematic review and guideline methodologists. The guideline panel referred to a formal process following the Recommendations, Assessment, Development, and Evaluation Working Group (GRADE) methodology to issue GRADEd recommendations. In this approach, panelists and methodologists formatted the questions, conducted systematic reviews, evaluated risk of bias, assessed certainty of evidence, and presented a summary of findings in a transparent fashion. For most recommendations, the task forces used a less structured approach largely based on narrative reviews to issue non-GRADEd recommendations. The panel issued Eight GRADEd recommendations (seven for hypoparathyroidism and one for hyperparathyroidism). Each GRADEd recommendation is linked to the underlying body of evidence and judgments regarding the certainty of evidence and strength of recommendations, values and preferences, and costs, feasibility, acceptability and equity. This article summarizes the methodology for issuing GRADEd and non-GRADEd recommendations for patients with hypoparathyroidism or hyperparathyroidism. © 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).