Cardiovascular Autonomic Neuropathy as a New Complication of Postsurgical Chronic Hypoparathyroidism

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.

Association of Serum Calcium and Phosphate With Incident Cardiovascular Disease in Patients With Hypoparathyroidism

The pathophysiological basis for the increased incidence of cardiovascular disease in patients with chronic hypoparathyroidism is poorly understood. To evaluate associations between levels of albumin-corrected serum calcium, serum phosphate, and calcium-phosphate product with the odds of developing cardiovascular events in patients with chronic hypoparathyroidism with ≥1 calcitriol prescription, we conducted a retrospective nested case-control study of patients who developed a cardiovascular event and matched controls without an event. The primary outcome was the instance of cardiovascular events. An electronic medical record database was used to identify 528 patients for the albumin-corrected serum calcium analysis and 200 patients for the serum phosphate and calcium-phosphate product analyses. Patients with ≥67% of albumin-corrected serum calcium measurements outside the study-defined 2.00 to 2.25 mmol/L (8.0 to 9.0 mg/100 ml) range had 1.9-fold higher odds of a cardiovascular event (adjusted odds ratio, 95% confidence interval 1.89, 1.10 to 3.25) compared with patients with <33% of calcium measurements outside the range. Likewise, patients with any serum phosphate measurements above 0.81 to 1.45 mmol/L (2.5 to 4.5 mg/100 ml) had 3.3-fold higher odds (3.26; 1.24 to 8.58), and those with any calcium-phosphate product measurements above 4.40 mmol²/L² (55 mg²/dL²) had 4.8-fold higher odds of a cardiovascular event (95% confidence interval 1.36 to 16.81) compared with patients with no measurements above these ranges. In adult patients with chronic hypoparathyroidism, a cardiovascular event was more likely in those with a higher proportion of albumin-corrected serum calcium measurements outside 2.00 to 2.25 mmol/L (8.0 to 9.0 mg/100 ml) or any serum phosphate and any calcium-phosphate product measurements above the normal population range.

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).

Safety and Efficacy of PTH 1-34 and 1-84 Therapy in Chronic Hypoparathyroidism: A Meta-Analysis of Prospective Trials

Hypoparathyroidism is the only endocrine deficiency for which hormone replacement therapy is not the standard of care. Although conventional treatments may control hypocalcaemia, other complications such as hyperphosphatemia, kidney stones, peripheral calcifications, and bone disease remain unmet needs. This meta-analysis (PROSPERO registration number CRD42019126881) aims to evaluate and compare the efficacy and safety of PTH_1-34 and PTH_1-84 in restoring calcium metabolism in chronic hypoparathyroidism. EMBASE, PubMed, and CENTRAL databases were searched for randomized clinical trials or prospective studies published between January 1996 and March 2021. English-language trials reporting data on replacement with PTH_1-34 or PTH_1-84 in chronic hypoparathyroidism were selected. Three authors extracted outcomes, one author performed quality control, all assessed the risk of biases. Overall, data from 25 studies on 588 patients were analyzed. PTH therapy had a neutral effect on calcium levels, while lowering serum phosphate (-0.21 mmol/L; 95% confidence interval [CI], -0.31 to -0.11 mmol/L; p < 0.001) and urinary calcium excretion (-1.21 mmol/24 h; 95% CI, -2.03 to -0.41 mmol/24 h; p = 0.003). Calcium phosphate product decreased under PTH_1-84 therapy only. Both treatments enabled a significant reduction in calcium and calcitriol supplementation. PTH therapy increased bone turnover markers and lumbar spine mineral density. Quality of life improved and there was no difference in the safety profile between PTH and conventionally treated patients. Results for most outcomes were similar for the two treatments. Limitations of the study included considerable population overlap between the reports, incomplete data, and heterogeneity in the protocol design. In conclusion, the meta-analysis of data from the largest collection to date of hypoparathyroid patients shows that PTH therapy is safe, well-tolerated, and effective in normalizing serum phosphate and urinary calcium excretion, as well as enabling a reduction in calcium and vitamin D use and improving quality of life. © 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).

Lower Risk of Cardiovascular Events in Adult Patients with Chronic Hypoparathyroidism Treated with rhPTH(1-84): A Retrospective Cohort Study

Introduction

Patients with chronic hypoparathyroidism are at increased risk of cardiovascular disease. This study evaluated the risk of developing cardiovascular conditions over a period of 5 years in adult patients with chronic hypoparathyroidism treated with recombinant human parathyroid hormone (1–84), rhPTH(1–84), compared with a historical control cohort of patients not treated with rhPTH(1–84).

Methods

This retrospective cohort study comprised patients with chronic hypoparathyroidism treated with rhPTH(1–84) in the REPLACE (NCT00732615), RELAY (NCT01268098), and RACE (NCT01297309) clinical trials, and controls selected from the IBM^® Explorys electronic medical record database (January 2007–August 2019) who did not receive parathyroid hormone but who had enrollment criteria similar to those for the clinical trials. Cardiovascular outcomes were the first diagnosis of cerebrovascular, coronary artery, peripheral vascular disease, or heart failure during the study period.

Results

We evaluated 113 adult patients with chronic hypoparathyroidism treated with rhPTH(1–84) and 618 control patients who did not receive rhPTH(1–84). Over the 5-year follow-up period, 3.5% of patients (n = 4) in the rhPTH(1–84) cohort had a cardiovascular event compared with 16.3% (n = 101) in the control cohort. Kaplan–Meier analysis demonstrated that patients in the rhPTH(1–84) cohort had lower risk of experiencing a cardiovascular event compared with patients in the control cohort (P = 0.005). Multivariable analyses adjusted for baseline variables showed that patients in the rhPTH(1–84) cohort had 75% lower risk for a cardiovascular event compared with patients in the control cohort (adjusted hazard ratio, 0.25 [95% CI 0.08–0.81]; P = 0.020).

Conclusion

Long-term treatment with rhPTH(1–84) was associated with a lower risk of incident cardiovascular conditions compared with conventional therapy in patients with chronic hypoparathyroidism. Previous studies demonstrated that mineral homeostasis was maintained with lower use of calcium and active vitamin D when rhPTH(1–84) was added to conventional therapy. Future studies are needed to understand whether improved regulation of mineral homeostasis conferred by rhPTH(1–84) may provide long-term cardiovascular benefits to patients with chronic hypoparathyroidism.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-022-02198-y.

The PARADIGHM (physicians advancing disease knowledge in hypoparathyroidism) registry for patients with chronic hypoparathyroidism: study protocol and interim baseline patient characteristics

BACKGROUND

The PARADIGHM registry of adult and pediatric patients with chronic hypoparathyroidism evaluates the long-term safety and effectiveness of treatment with recombinant human parathyroid hormone, rhPTH(1-84), and describes the clinical disease course under conditions of routine clinical practice. In this first report, we detail the registry protocol and describe the baseline characteristics of two adult patient cohorts from an interim database analysis. One cohort after study entry were prescribed rhPTH(1-84), and the other cohort received conventional therapy of calcium and active vitamin D.

METHODS

An observational study of patients with chronic hypoparathyroidism in North America and Europe, collecting data for ≥10 years per patient. Main outcome measures were baseline patient demographics, clinical characteristics, medications, and disease outcome variables of symptoms, biochemical parameters, and health assessments. Baseline is the enrollment assessment for all variables except biochemical measurements in patients treated with rhPTH(1-84); those measurements were the most recent value before the first rhPTH(1-84) dose. Exclusion criteria applied to the analysis of specified outcomes included pediatric patients, patients who initiated rhPTH(1-84) prior to enrollment, and those who received rhPTH(1-34). Clinically implausible biochemical outlier data were excluded.

RESULTS

As of 30 June 2019, data of 737 patients were analyzed from 64 centers; 587 (80%) were women, mean ± SD age 49.1±16.45 years. At enrollment, symptoms reported for patients later prescribed rhPTH(1-84) (n=60) and those who received conventional therapy (n=571), respectively, included fatigue (51.7%, 40.1%), paresthesia (51.7%, 29.6%), muscle twitching (48.3%, 21.9%), and muscle cramping (41.7%, 33.8%). Mean serum total calcium, serum phosphate, creatinine, and estimated glomerular filtration rate were similar between cohorts. Health-related quality of life (HRQoL) 36-item Short Form Health Survey questionnaire scores for those later prescribed rhPTH(1-84) were generally lower than those for patients in the conventional therapy cohort.

CONCLUSIONS

At enrollment, based on symptoms and HRQoL, a greater percentage of patients subsequently prescribed rhPTH(1-84) appeared to have an increased burden of disease than those who received conventional therapy despite having normal biochemistry measurements. PARADIGHM will provide valuable real-world insights on the clinical course of hypoparathyroidism in patients treated with rhPTH(1-84) or conventional therapy in routine clinical practice.

TRIAL REGISTRATION

EUPAS16927, NCT01922440.

Risk of Cardiovascular Conditions in Patients with Chronic Hypoparathyroidism: A Retrospective Cohort Study

Introduction

In patients with chronic hypoparathyroidism disordered calcium homeostasis has been associated with risk of cardiovascular diseases, including cardiomyopathy, congestive heart failure, and arrhythmia; however, larger-scale studies are needed to examine these risks. This study evaluated the risk of cardiovascular conditions among patients with chronic hypoparathyroidism.

Methods

Adults with and without chronic hypoparathyroidism were selected from a medical insurance claims database in the USA from January 2007 to June 2017, and were followed for up to 5 years. Associations between chronic hypoparathyroidism and incident atrial fibrillation (AF), tachyarrhythmia, myocardial infarction (MI), coronary artery disease (CAD), heart failure (HF), stroke, cerebrovascular disease, peripheral vascular disease (PVD), and a combined cardiovascular endpoint of cerebrovascular disease, CAD, HF, and PVD were compared between cohorts using Kaplan–Meier analyses and unadjusted and adjusted Cox proportional hazards models.

Results

In 8097 patients with chronic hypoparathyroidism compared with 40,485 patients without, respectively, mean ± SD ages were 58.6 ± 16.3 and 47.3 ± 18.0 years, 76.2% and 54.4% were female, and 19.4% and 9.5% had the combination of cardiovascular findings at baseline. In adjusted analyses, patients with chronic hypoparathyroidism had significantly higher risk (adjusted hazard ratio and 95% confidence interval) of incident AF (1.72; 1.51–1.97), tachyarrhythmia (1.68; 1.32–2.14), MI (1.18; 1.01–1.38), CAD (1.39; 1.26–1.54), HF (1.64; 1.46–1.84), stroke (1.45; 1.31–1.62), cerebrovascular disease (1.48; 1.34–1.62), PVD (1.66; 1.51–1.81), and combined cardiovascular endpoint (1.63; 1.52–1.75), all P < 0.001 except P = 0.036 for MI, compared with patients without chronic hypoparathyroidism.

Conclusions

This large retrospective cohort study showed that chronic hypoparathyroidism was associated with increased risk of incident cardiovascular conditions and arrhythmias. Results should be evaluated in light of limitations inherent to claims database analyses. Further studies are warranted to investigate reasons for these risks and to develop strategies for reducing cardiovascular conditions in patients with chronic hypoparathyroidism.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01787-7.

Diagnosis and management of hypocalcemia

The aim of this clinical narrative review is to summarize and critically appraise the literature on the differential diagnosis of hypocalcemia and to provide its correct management. Calcium is essential for muscle contraction and neurotransmitter release, but clinical manifestations of hypocalcaemia (serum calcium level <8 mg/dl; 2.12 mmol/L) may involve almost any organ and system and may range from asymptomatic to life-threating conditions. Disorders causing hypocalcemia can be divided into parathyroid hormone (PTH) and non-PTH mediated. The most frequent cause of hypocalcemia is postsurgical hypoparathyroidism, while a more comprehensive search for other causes is needed for appropriate treatment in the non PTH-mediated forms. Intravenous calcium infusion is essential to raise calcium levels and resolve or minimize symptoms in the setting of acute hypocalcemia. Oral calcium and/or vitamin D supplementation is the most frequently used as treatment of chronic hypocalcemia. In hypoparathyroidism, providing the missing hormone with the use of the recombinant human (rh) PTH(1-84) has been recently approved both by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA). This new therapy has the advantage of being effective for correcting serum calcium levels and significantly reducing the daily requirements of calcium and active vitamin D supplements. However, due to the high cost, a strict selection of candidates to this therapy is necessary. More challenging is the long-term hypocalcemia treatment, due to its associated complications. The development of long-acting recombinant human PTH will probably modify the management of chronic hypoparathyroidism in the future.

Quantification of Symptom Load by a Disease-Specific Questionnaire HPQ 28 and Analysis of Associated Biochemical Parameters in Patients With Postsurgical Hypoparathyroidism

In hypoparathyroidism (HypoPT), patients suffer severely from reduced quality of life. The complexity of HypoPT demands a disease‐specific control instrument to characterize symptom load. We employed a newly developed disease‐specific Hypoparathyroid Patient Questionnaire (the HPQ 40/28) to investigate and quantify HypoPT patients' complaints and contributing factors. In this cross‐sectional, two‐center study, patients with postsurgical HypoPT (n = 49) were matched for gender and age and compared with patients having undergone thyroid surgery without HypoPT (n = 39) and patients with primary hyperparathyroidism (n = 35). The HPQ 40/28 was completed when patients visited the respective center. Clinical background information, blood tests, and current medication were documented by the physician. Serum calcium lay within the reference range in 87% of HypoPT patients, serum phosphate in 95.7%, and calcium–phosphate product (CPP) in 100%. HPQ 40/28 scores for the scales “pain and cramps” (PaC), “neurovegetative symptoms” (NVS), “numbness or tingling,” and “heart palpitations” were significantly elevated in comparison with control groups. Correlations between complaints and laboratory parameters could be demonstrated in the HypoPT group, with serum calcium correlating with NVS (r = 0.309, p < 0.05) and serum phosphate with loss of vitality (r = 0.349, p < 0.05). CPP was the main contributor to symptom load with an influence on PaC (r = 0.295, p < 0.05), loss of vitality (r = 0.498, p < 0.001), numbness or tingling (r = 0.328, p < 0.05), and memory problems (r = 0.296, p < 0.05). In conclusion, the newly developed HPQ 40/28 successfully identified and quantified symptoms typical in HypoPT patients. Using the HPQ 40/28, the CPP was identified as the predominant factor in the severity of complaints in HypoPT. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Hypoparathyroidism

BACKGROUND

Hypoparathyroidism is a rare endocrine disorder characterized by hypocalcemia and low or undetectable levels of parathyroid hormone.

METHODS

This review is an evidence-based summary of hypoparathyroidism in terms of relevant pathophysiological, clinical, and therapeutic concepts.

RESULTS

Many clinical manifestations of hypoparathyroidism are due to the lack of the physiological actions of parathyroid hormone on its 2 major target organs: the skeleton and the kidney. The skeleton is inactive, accruing bone without remodeling it. The kidneys lose the calcium-conserving actions of parathyroid hormone and, thus, excrete a greater fraction of calcium. Biochemical manifestations, besides hypocalcemia and low or undetectable levels of parathyroid hormone, include hyperphosphatemia and low levels of 1,25-dihydroxyvitamin D. Calcifications in the kidney, brain, and other soft tissues are common. Removal of, or damage to, the parathyroid glands at the time of anterior neck surgery is, by far, the most likely etiology. Autoimmune destruction of the parathyroid glands and other genetic causes represent most of the other etiologies. Conventional treatment with calcium and active vitamin D can maintain the serum calcium level but high doses may be required, adding to the risk of long-term soft tissue calcifications. The advent of replacement therapy with recombinant human PTH(1-84) represents a major step in the therapeutics of this disease.

CONCLUSIONS

Advances in our knowledge of hypoparathyroidism have led to greater understanding of the disease itself and our approach to it.

Cardiovascular autonomic neuropathy as a cause of fatigue in chronic hypoparathyroidism

PURPOSE

Hypoparathyroidism (hypoPT) results in an impairment of quality of life (QoL), an increase in fatigue and a higher risk of mortality. Cardiovascular autonomic neuropathy (CAN) is an impairment of the cardiovascular autonomic system and is associated with increased mortality and fatigability. Patients with hypoPT show an increased risk of CAN. However, no previous studies have investigated the association between CAN and QoL in hypoPT. To test whether CAN is associated with fatigue and impaired QOL in hypoPT patients.

METHODS

We enrolled 48 subjects with postsurgical hypoPT treated with calcium and calcitriol and 38 healthy subjects who underwent thyroidectomy. Subjects completed the RAND 36-Item Short Form (SF-36) Health Survey, evaluating physical (PCS) and mental (MCS) health, and fatigue score. CAN was assessed using cardiovascular autonomic reflex tests (CARTs). Participants were considered to have "early CAN" (EC) if they had one abnormal CART and "definite CAN" (DC) with two or more abnormal CARTs.

RESULTS

Compared with controls, hypoPT population had lower fatigue scores (44.5 IQRː9 vs 38.5 IQRː12.3, P = 0.031). In the hypoPT group, only participants with DC had a lower fatigue score than subjects without CAN (DC: β: -9.55, P = 0.005) after adjusting for age, duration of disease, calcium concentration, TSH, calcitriol and calcium supplementation. No differences were found in the PCS and MCS scores in the hypoPT group.

CONCLUSIONS

CAN may explain fatigue, a common complaint of postsurgical hypoPT patients. Further larger and prospective investigations are needed to confirm our findings.