What predicts adverse outcomes in untreated primary hyperparathyroidism? The Parathyroid Epidemiology and Audit Research Study (PEARS)

Association between primary hyperparathyroidism and cardiovascular outcomes: A systematic review and meta-analysis

BACKGROUND

Excess parathyroid hormone (PTH) is associated with an increased risk of cardiovascular disease (CVD).

PURPOSE

We aimed to evaluate the correlation between primary hyperparathyroidism (PHPT) and CVD or cardiovascular (CV) death.

DATA SOURCES

Comprehensive searches of PubMed, Embase and ClinicalTrials.gov until May 20, 2023 with the following keywords: "primary hyperparathyroidism," "cardiovascular disease," and "mortality."

STUDY SELECTIONS

Cohort studies and randomized controlled trials comparing PHPT patients to the general population and those who had received parathyroidectomy (PTX) to those who did not.

DATA EXTRACTION

Three investigators independently extracted data and assessed study quality.

DATA SYNTHESIS

Eleven cohort studies and one randomized controlled trial were identified, including 264,227 PHPT patients with or without PTX, and the average age reported in the studies was 62 years. PHPT was associated with a higher risk of total death (RR 1.39 [95 % confidence interval (CI) 1.23-1.57) and CV death (RR 1.61 [95 % CI 1.47-1.78]) than the general population. However, there was no significant difference in CVD risk between patients with PHPT and the general population (RR 1.73 [95 % CI 0.87-3.47]). When compared to patients without PTX, PTX had a lower risk of CV death (RR 0.75 [95 % CI 0.71-0.80]), total death (RR 0.64 [95 % CI 0.60-0.70]) and CVD (RR 0.92 [95 % CI 0.90-0.94]).

LIMITATION

High heterogeneity among the included articles, and most of them were retrospective and older studies.

CONCLUSIONS

PHPT was associated with higher risk of total death and CV death while PTX was associated with lower risk of total death, CV death, and CVD.

Parathyroid hormone-PTH1R signaling in cardiovascular disease and homeostasis

Primary hyperparathyroidism (pHPT) afflicts our aging population with an incidence approaching 50 per 100 000 patient-years at a female:male ratio of ~3:1. Decisions surrounding surgical management are currently driven by age, hypercalcemia severity, presence of osteoporosis, renal insufficiency, or hypercalciuria with or without nephrolithiasis. Cardiovascular (CV) disease (CVD) is not systematically considered. This is notable since the parathyroid hormone (PTH) 1 receptor (PTH1R) is biologically active in the vasculature, and adjusted CV mortality risk is increased almost threefold in individuals with pHPT who do not meet contemporary recommendations for surgical cure. We provide an overview of epidemiology, pharmacology, and physiology that highlights the need to: (i) identify biomarkers that establish a healthy 'set point' for CV PTH1R signaling tone; (ii) better understand the pharmacokinetic-pharmacodynamic (PK-PD) relationships of PTH1R ligands in CV homeostasis; and (iii) incorporate CVD risk assessment into the management of hyperparathyroidism.

Epidemiology, Pathophysiology, and Genetics of Primary Hyperparathyroidism

In this narrative review, we present data gathered over four decades (1980-2020) on the epidemiology, pathophysiology and genetics of primary hyperparathyroidism (PHPT). PHPT is typically a disease of postmenopausal women, but its prevalence and incidence vary globally and depend on a number of factors, the most important being the availability to measure serum calcium and parathyroid hormone levels for screening. In the Western world, the change in presentation to asymptomatic PHPT is likely to occur, over time also, in Eastern regions. The selection of the population to be screened will, of course, affect the epidemiological data (ie, general practice as opposed to tertiary center). Parathyroid hormone has a pivotal role in regulating calcium homeostasis; small changes in extracellular Ca++ concentrations are detected by parathyroid cells, which express calcium-sensing receptors (CaSRs). Clonally dysregulated overgrowth of one or more parathyroid glands together with reduced expression of CaSRs is the most important pathophysiologic basis of PHPT. The spectrum of skeletal disease reflects different degrees of dysregulated bone remodeling. Intestinal calcium hyperabsorption together with increased bone resorption lead to increased filtered load of calcium that, in addition to other metabolic factors, predispose to the appearance of calcium-containing kidney stones. A genetic basis of PHPT can be identified in about 10% of all cases. These may occur as a part of multiple endocrine neoplasia syndromes (MEN1-MEN4), or the hyperparathyroidism jaw-tumor syndrome, or it may be caused by nonsyndromic isolated endocrinopathy, such as familial isolated PHPT and neonatal severe hyperparathyroidism. DNA testing may have value in: confirming the clinical diagnosis in a proband; eg, by distinguishing PHPT from familial hypocalciuric hypercalcemia (FHH). Mutation-specific carrier testing can be performed on a proband's relatives and identify where the proband is a mutation carrier, ruling out phenocopies that may confound the diagnosis; and potentially prevention via prenatal/preimplantation diagnosis. © 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).

Classical and Nonclassical Manifestations of Primary Hyperparathyroidism

This narrative review summarizes data on classical and nonclassical manifestations of primary hyperparathyroidism (PHPT). It is based on a rigorous literature search, inclusive of a Medline search for systematic reviews from 1940 to December 2020, coupled with a targeted search for original publications, covering four databases, from January 2013-December 2020, and relevant articles from authors' libraries. We present the most recent information, identify knowledge gaps, and suggest a research agenda. The shift in the presentation of PHPT from a predominantly symptomatic to an asymptomatic disease, with its varied manifestations, has presented several challenges. Subclinical nephrolithiasis and vertebral fractures are common in patients with asymptomatic disease. The natural history of asymptomatic PHPT with no end organ damage at diagnosis is unclear. Some observational and cross-sectional studies continue to show associations between PHPT and cardiovascular and neuropsychological abnormalities, among the different disease phenotypes. Their causal relationship is uncertain. Limited new data are available on the natural history of skeletal, renal, cardiovascular, neuropsychological, and neuromuscular manifestations and quality of life. Normocalcemic PHPT (NPHPT) is often diagnosed without the fulfillment of rigorous criteria. Randomized clinical trials have not demonstrated a consistent long-term benefit of parathyroidectomy (PTX) versus observation on nonclassical manifestations. We propose further refining the definition of asymptomatic disease, into two phenotypes: one without and one with evidence of target organ involvement, upon the standard evaluation detailed in our recommendations. Each of these phenotypes can present with or without non-classical manifestations. We propose multiple albumin-adjusted serum calcium determinations (albumin-adjusted and ionized) and exclusion of all secondary causes of high parathyroid hormone (PTH) when establishing the diagnosis of NPHPT. Refining the definition of asymptomatic disease into the phenotypes proposed will afford insights into their natural history and response to interventions. This would also pave the way for the development of evidence-based guidance and recommendations. © 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 Primary Hyperparathyroidism: Summary Statement and Guidelines from the Fifth International Workshop

The last international guidelines on the evaluation and management of primary hyperparathyroidism (PHPT) were published in 2014. Research since that time has led to new insights into epidemiology, pathophysiology, diagnosis, measurements, genetics, outcomes, presentations, new imaging modalities, target and other organ systems, pregnancy, evaluation, and management. Advances in all these areas are demonstrated by the reference list in which the majority of listings were published after the last set of guidelines. It was thus, timely to convene an international group of over 50 experts to review these advances in our knowledge. Four Task Forces considered: 1. Epidemiology, Pathophysiology, and Genetics; 2. Classical and Nonclassical Features; 3. Surgical Aspects; and 4. Management. For Task Force 4 on the Management of PHPT, Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) methodology addressed surgical management of asymptomatic PHPT and non-surgical medical management of PHPT. The findings of this systematic review that applied GRADE methods to randomized trials are published as part of this series. Task Force 4 also reviewed a much larger body of new knowledge from observations studies that did not specifically fit the criteria of GRADE methodology. The full reports of these 4 Task Forces immediately follow this summary statement. Distilling the essence of all deliberations of all Task Force reports and Methodological reviews, we offer, in this summary statement, evidence-based recommendations and guidelines for the evaluation and management of PHPT. Different from the conclusions of the last workshop, these deliberations have led to revisions of renal guidelines and more evidence for the other recommendations. The accompanying papers present an in-depth discussion of topics summarized in this report. © 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).

Effect of Parathyroidectomy on Metabolic Homeostasis in Primary Hyperparathyroidism

Background: The benefits of parathyroidectomy on cardiovascular risk in primary hyperparathyroidism (PHPT) are controversial. This monocentric, observational, prospective study aimed to assess the effects of parathyroidectomy on glucose and lipid metabolism in classic or mild PHPT. Methods: Patients who underwent parathyroidectomy for classic (calcemia >2.85 mmol/L) or mild PHPT (calcemia ≤2.85 mmol/L) between 2016 and 2019 were included. A metabolic assessment was performed before and 1 year after parathyroidectomy. Patients with a history of diabetes were excluded. Results: Nineteen patients had classic and 120 had mild PHPT. Ninety-five percent were normocalcemic 6 months after surgery. Fasting plasma glucose and insulin levels decreased after parathyroidectomy in patients with mild PHPT (p < 0.001). HOMA-IR decreased after surgery in the overall population (p < 0.001), while plasma adiponectin concentrations increased in patients with both classic (p = 0.005) and mild PHPT (p < 0.001). Plasma triglyceride levels decreased significantly only in patients with classic PHPT (p = 0.021). Plasma PCSK9 levels decreased in patients with mild PHPT (p < 0.001). Conclusions: Parathyroidectomy for PHPT improves insulin resistance and decreases plasma triglyceride levels in classic PHPT and plasma PCSK9 levels in mild PHPT. Further studies are needed to better characterize the consequences of such metabolic risk factors’ improvements on cardiovascular events.

Baseline renal dysfunction determines mortality following parathyroidectomy in primary hyperparathyroidism: analysis of Indian PHPT registry

INTRODUCTION

Primary hyperparathyroidism (PHPT) in India is mostly symptomatic with renal and skeletal complications. Evidence on mortality outcomes following parathyroidectomy from India, where the disease is predominantly symptomatic is limited.

MATERIAL AND METHODS

This was a prospective study to evaluate mortality outcomes in the Indian PHPT registry over the past 25 years (n = 464). Pre- and postoperative parameters and mortality data were obtained from medical records and/or by verbal autopsy, a method validated by WHO for data collection in settings where several deaths are noninstitutional. Patients were divided into survivor (SG) and nonsurvivor groups (NSG) to ascertain differences in presentation and the effect of parathyroidectomy.

RESULTS

The overall mortality was 8.8% at a median follow-up of 8 years (IQR 1-13) after parathyroidectomy. Chronic kidney disease was the most common background cause of death (43.5%), followed by pancreatitis (28.2%). NSG had significantly more frequent renal dysfunction (91.9% vs 73.9%), anaemia (50 vs 16.6%) and pancreatitis (24.3 vs 6.4%). PTH (61.9 vs 38.3 pmol/l) and baseline creatinine (97.2 vs 70.7 µmol/l) were significantly higher and eGFR lower (66.7 vs 90.7 ml/min/1.73m²) in the NSG than SG. By Cox proportional modelling, renal dysfunction [HR 2.88 (1.42-5.84)], anaemia [HR 2.45 (1.11-5.42)] and pancreatitis [HR 2.65 (1.24-5.66)] on univariate and renal dysfunction [HR 3.33 (1.13-9.77)] on multivariate analysis were significant for mortality. Survival curves demonstrated a significantly higher mortality with lower eGFR values.

CONCLUSIONS

Nonsurvivors in PHPT had greater prevalence and more severe baseline renal dysfunction than survivors. Survival after parathyroidectomy was significantly associated with estimated glomerular filtration rate at baseline.

Survival in primary hyperparathyroidism over five decades (1965-2010) a population-based retrospective study

CONTEXT

Survival in patients with primary hyperparathyroidism (PHPT) remains uncertain.

OBJECTIVE

To update survival in patients with PHPT in a United States community population.

DESIGN

Retrospective cohort study.

SETTING

Community population in Rochester, Minnesota.

PARTICIPANTS

Residents who met criteria for PHPT from 1965 to 2010.

INTERVENTIONS

Survival was estimated using the Kaplan Meier product-limit method. The Cox proportional hazards model was used to determine associations, as relative hazards (RR) with 95% confidence intervals (CI), of various risk factors with time to death.

MAIN OUTCOME MEASURE

The overall age and gender-adjusted survival compared to white Minnesota residents.

RESULTS

We identified 1139 PHPT individuals, 76% female, with a median age of 58 years. Most were observed without parathyroidectomy (69%). The relative risk of death among the entire cohort was 0.996 (95% CI: 0.91-1.09, P = 0.935) which was not different compared to Minnesota residents. Those with maximum serum calcium level ≥ 10.8 mg/dL (0.7 mg/dL above the reference range) had an increase in mortality (RR 1.32, 95% CI: 1.10-1.58, P = 0.002). Survival among all PHPT individuals after parathyroidectomy was no different from expected (RR = 1.06, 95% CI 0.89-1.28; P = 0.508). Mortality was significantly decreased after parathyroidectomy in those with serum calcium levels ≥10.8 mg/dL (HR 0.47, 95% CI: 0.36-0.61, P < 0.001).

CONCLUSIONS

Mortality in the entire cohort was not different from expected. PHPT patients with a maximum serum calcium level ≥ 10.8 mg/dL had increased mortality. Survival was improved after parathyroidectomy in those with this degree of hypercalcemia.

Cardiovascular Risk in Patients with Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is one of the most common endocrine disorders characterized by parathyroid hormone (PTH)-dependent hypercalcemia. Cardinal features include low trauma fractures, nephrolithiasis, and chronic kidney disease. Several experimental studies established that parathyroid hormone exerts actions on the cardiovascular (CV) system, including vasodilatation and positive inotropic and chronotropic effects. Observational studies, especially in severe cases, report a higher prevalence of hypertension, diabetes mellitus, lipid abnormalities, endothelial dysfunction, arrhythmias, and left ventricular hypertrophy in patients with PHPT, while the risk of CV events seems to be increased in severe cases. However, the effect of surgery is inconsistent on CV abnormalities and, more importantly, on CV disease (CVD) events, especially in mild cases. In the current review, we describe the available evidence linking PHPT and CVD, as well as the effect of surgical management and pharmacological treatment on CVD manifestations in patients with PHPT. Based on the current evidence, CVD is not considered an indication for surgery.

Impact of parathyroidectomy on cardiovascular risk in primary hyperparathyroidism: A narrative review

AIMS

Primary hyperparathyroidism (PHPT), one of the most frequent endocrine disorders, is not only associated with bone and kidney disorders but also with increased cardiovascular risk. This cardiovascular risk is not part of the indication for surgery owing to discordant evidence of the effects of parathyroidectomy (PTX), especially in mild PHPT which is the most common presentation of PHPT. This literature review focuses on the effects of PTX on the cardiovascular risk in PHPT. The MEDLINE database was searched via the PubMed interface, selecting relevant articles published after 1990 in English.

DATA SYNTHESIS

In the most recent series, PTX appeared to have a positive impact on cardiovascular morbidity and mortality. Surgery improves arterial hypertension, markers of glucose homeostasis, vascular and cardiac remodeling and electrocardiographic impairments due to classical PHPT. However, the results of surgery on mild PHPT are conflicting.

CONCLUSIONS

PTX seems to improve cardiovascular risk in patients presenting the classical form of PHPT. This improvement is correlated with preoperative serum calcium and/or PTH level, depending on the cardiovascular risk factor. However, many aspects of this improvement are not fully understood. Future studies should assess the effects of PTX on nocturnal hypertension, cardiac morphology and functions. The results for mild PHPT are conflicting owing to the limited size of the cohorts included in studies and the lack of randomized trials. Surgery is not currently recommended for patients presenting mild PHPT based on the cardiovascular risk and more studies are needed to better understand the interest of PTX on cardiovascular outcomes.

Physical Activity-Dependent Regulation of Parathyroid Hormone and Calcium-Phosphorous Metabolism

Exercise perturbs homeostasis, alters the levels of circulating mediators and hormones, and increases the demand by skeletal muscles and other vital organs for energy substrates. Exercise also affects bone and mineral metabolism, particularly calcium and phosphate, both of which are essential for muscle contraction, neuromuscular signaling, biosynthesis of adenosine triphosphate (ATP), and other energy substrates. Parathyroid hormone (PTH) is involved in the regulation of calcium and phosphate homeostasis. Understanding the effects of exercise on PTH secretion is fundamental for appreciating how the body adapts to exercise. Altered PTH metabolism underlies hyperparathyroidism and hypoparathyroidism, the complications of which affect the organs involved in calcium and phosphorous metabolism (bone and kidney) and other body systems as well. Exercise affects PTH expression and secretion by altering the circulating levels of calcium and phosphate. In turn, PTH responds directly to exercise and exercise-induced myokines. Here, we review the main concepts of the regulation of PTH expression and secretion under physiological conditions, in acute and chronic exercise, and in relation to PTH-related disorders.

PTH/PTHrP Receptor Signaling Restricts Arterial Fibrosis in Diabetic LDLR-/- Mice by Inhibiting Myocardin-Related Transcription Factor Relays

RATIONALE

The PTH1R (PTH [parathyroid hormone]/PTHrP [PTH-related protein] receptor) is expressed in vascular smooth muscle (VSM) and increased VSM PTH1R signaling mitigates diet-induced arteriosclerosis in LDLR-/- mice.

OBJECTIVE

To study the impact of VSM PTH1R deficiency, we generated mice SM22-Cre:PTH1R(fl/fl);LDLR-/- mice (PTH1R-VKO) and Cre-negative controls.

METHODS AND RESULTS

Immunofluorescence and Western blot confirmed PTH1R expression in arterial VSM that was reduced by Cre-mediated knockout. PTH1R-VKO cohorts exhibited increased aortic collagen accumulation in vivo, and VSM cultures from PTH1R-VKO mice elaborated more collagen (2.5-fold; P=0.01) with elevated Col3a1 and Col1a1 expression. To better understand these profibrotic responses, we performed mass spectrometry on nuclear proteins extracted from Cre-negative controls and PTH1R-VKO VSM. PTH1R deficiency reduced Gata6 but upregulated the MADS (MCM1, Agamous, Deficiens, and Srf DNA-binding domain)-box transcriptional co-regulator, Mkl-1 (megakaryoblastic leukemia [translocation] 1). Co-transfection assays (Col3a1 promoter-luciferase reporter) confirmed PTH1R-mediated inhibition and Mkl-1-mediated activation of Col3a1 transcription. Regulation mapped to a conserved hybrid CT(A/T)6GG MADS-box cognate in the Col3a1 promoter. Mutations of C/G in this motif markedly reduced Col3a1 transcriptional regulation by PTH1R and Mkl-1. Upregulation of Col3a1 and Col1a1 in PTH1R-VKO VSM was inhibited by small interfering RNA targeting Mkl1 and by treatment with the Mkl-1 antagonist CCG1423 or the Rock (Rho-associated coiled-coil containing protein kinase)-2 inhibitor KD025. Chromatin precipitation demonstrated that VSM PTH1R deficiency increased Mkl-1 binding to Col3a1 and Col1a1, but not TNF, promoters. Proteomic studies of plasma extracellular vesicles and VSM from PTH1R-VKO mice identified C1r (complement component 1, r) and C1s (complement component 1, s), complement proteins involved in vascular collagen metabolism, as potential biomarkers. VSM C1r protein and C1r message were increased with PTH1R deficiency, mediated by Mkl-1-dependent transcription and inhibited by CCG1423 or KD025.

CONCLUSIONS

PTH1R signaling restricts collagen production in the VSM lineage, in part, via Mkl-1 regulatory circuits that control collagen gene transcription. Strategies that maintain homeostatic VSM PTH1R signaling, as reflected in extracellular vesicle biomarkers of VSM PTH1R/Mkl-1 action, may help mitigate arteriosclerosis and vascular fibrosis.

Cardiovascular consequences of parathyroid disorders in adults

PTH is a metabolic active hormone primarily regulating calcium and phosphate homeostasis in a very tight and short term-manner. Parathyroid disorders in adult patients reflect a variety of different conditions related either to the parathyroid glands itself or to the effects of the secreted hormone. The clinical spectrum varies from the common disease primary hyperparathyroidism (PHPT) to the orphan conditions pseudohypoparathyroidism (Ps-HypoPT) and chronic hypoparathyroidism (HypoPT). The purpose of this review is to describe the consequences of disturbances in levels or action of PTH for cardiac function and cardiovascular risk in adult patients with these disorders. Most patients with PHPT achieve the diagnose by chance and have minor or no specific symptoms. Still, these patients with mild PHPT do possess cardiovascular (CV) morbidity, however so far not proven ameliorated by surgery in controlled trials. In severe cases, the CV risk is increased and with a potential reversibility by treatment. Patients with Ps-HypoPT have resistance to PTH action, but not necessarily total resistance in all tissues. So far, no clear CV morbidity or risk has been demonstrated, but there are several aspects of interest for further studies. Most patients with HypoPT do get their hormonal deficiency syndrome following neck surgery. These patients do experience multiple symptoms and do have an increased CV-risk before the primary surgery. Based on existing data, their CV mortality do not deviate from the expected when adjusting for the preexisting increased risk. Patients with nonsurgical (NS-) HypoPT do demonstrate increased CV-risk also associated with exposure time. Endocrine disorders with alterations in PTH function have major impact on the cardiovascular system of importance for morbidity and mortality, wherefore management of these specific diseases should be optimized currently, as new data become available, however also avoiding over-treating asymptomatic patients.

Primary hyperparathyroidism and hypertension

Although untreated primary hyperparathyroidism is associated with increased cardiovascular mortality, controversy exists regarding the therapeutic effects of parathyroidectomy on cardiovascular health. This review will examine the evidence linking primary hyperparathyroidism (PHPT) and cardiovascular disease, specifically hypertension, and evaluate the available literature regarding the natural history of hypertension after successful parathyroidectomy.

Parathyroid hormone independently predicts fracture, vascular events, and death in patients with stage 3 and 4 chronic kidney disease

Doctors do not know whether treatment of high parathyroid hormone levels is linked to better outcomes in their patients with kidney disease. In this study, lower parathyroid hormone levels at baseline were linked to lower risk of fracture, vascular events, and death in people with kidney disease.

PURPOSE

Chronic kidney disease (CKD) affects ~ 20% of older adults, and secondary hyperparathyroidism (HPT) is a common condition in these patients. To what degree HPT predicts fractures, vascular events, and mortality in pre-dialysis CKD patients is debated. In stage 3 and 4 CKD patients, we assessed relationships between baseline serum PTH levels and subsequent 10-year probabilities of clinical fractures, vascular events, and death.

METHODS

We used Marshfield Clinic Health System electronic health records to analyze data from adult CKD patients receiving care between 1985 and 2013, and whose PTH was measured using a second-generation assay. Covariates included PTH, age, gender, tobacco use, vascular disease, diabetes, hypertension, hyperlipidemia, obesity, GFR, and use of osteoporosis medications.

RESULTS

Five thousand one hundred eight subjects had a mean age of 68 ± 17 years, 48% were men, and mean follow-up was 23 ± 10 years. Fractures, vascular events, and death occurred in 18%, 71%, and 56% of the cohort, respectively. In univariate and multivariate models, PTH was an independent predictor of fracture, vascular events, and death. The hazards of fracture, vascular events and death were minimized at a baseline PTH of 0, 69, and 58 pg/mL, respectively.

CONCLUSIONS

We found that among individuals with stage 3 and 4 CKD, PTH was an independent predictor of fractures, vascular events, and death. Additional epidemiologic studies are needed to confirm these findings. If a target PTH range can be confirmed, then randomized placebo-controlled trials will be needed to confirm that treating HPT reduces the risk of fracture, vascular events, and death.

Predictors of Nephrolithiasis, Osteoporosis, and Mortality in Primary Hyperparathyroidism

CONTEXT

Primary hyperparathyroidism (PHPT) has a prevalence of 0.86% and is associated with increased risk of nephrolithiasis and osteoporosis. PHPT may also be associated with increased risk of cardiovascular disease and mortality.

OBJECTIVE

To identify risk factors for nephrolithiasis, osteoporosis, and mortality in PHPT.

DESIGN

Retrospective cohort study.

SETTING

University teaching hospital.

PATIENTS

Presented with PHPT between 2006 and 2014 (n = 611).

MAIN OUTCOME MEASURE

Assessment of nephrolithiasis, osteoporosis, and mortality.

RESULTS

Of patients with PHPT, 13.9% had nephrolithiasis. Most had previously documented stone disease, and only 4.7% of asymptomatic patients who were screened for renal stones had calculi identified, not very dissimilar to the rate in the non-PHPT population. Younger age (P < 0.001) and male sex (P = 0.003) were the only independent predictors of nephrolithiasis. Of patients with dual-energy X-ray absorptiometry data, 48.4% had osteoporosis (223/461). Older age (P < 0.001), lower body mass index (P = 0.002), and lower creatinine (P = 0.006) were independently associated with a diagnosis of osteoporosis. Higher PTH was independently associated with lower z score at the hip (P = 0.009); otherwise, calcium and PTH were not associated with lower z scores. Mortality in PHPT was associated with older age (P < 0.008), social deprivation (P = 0.028), and adjusted calcium (P = 0.009) but not independently with PTH at diagnosis.

CONCLUSIONS

Screening for nephrolithiasis has a low yield, particularly in lower risk patients. Osteoporosis is only minimally associated with biochemical indices of PHPT. Mortality is associated with higher calcium (and possibly vitamin D deficiency) but not PTH.

Asymptomatic and normocalcemic hyperparathyroidism, the silent attack: a combo-endocrinology overview

Asymptomatic primary hyperparathyroidism (PHPT) and the new variant of PHPT, normocalcemic PHPT, are considered by many physicians as mild, innocuous forms of disease, requiring nothing more than monitoring. Although this may be true in some cases in which the disease does not progress or cause complications, deterioration with more or less severe manifestations may occur. In the present review, we discuss the existing evidence of both the classic (skeletal and renal) and non-classic (cardiovascular, gastrointestinal, and psychiatric) features that have been attributed to asymptomatic and normocalcemic PHPT and the treatment effect on them.

Primary hyperparathyroidism: findings from the retrospective evaluation of cases over a 6-year period from a regional UK centre

BACKGROUND

Although there are international guidelines on diagnosis and management of primary hyperparathyroidism (PHPT), clinical practice varies in different centres. Periodic review of diagnostic work-up, surgical treatment by parathyroidectomy (PTX) and clinical surveillance in nonsurgical treatment group among patients with PHPT is expected to improve the quality of care. We report a retrospective study of cases with PHPT managed at a regional centre in the United Kingdom.

METHODS

Clinical data of cases with calcium ≥2.6 mmol/L and parathyroid hormone (PTH) ≥9.0 pmol/L was procured from biochemistry database from January 2011 to December 2016. Laboratory parameters, imaging studies for renal stones, osteoporosis and localisation of parathyroid adenomas, type of treatment received (PTX or nonsurgical), complications of treatment, other medical co-morbidities and mortality during follow-up was recorded in each case to examine the outcomes of care of patients with PHPT.

RESULTS

The study included 160 patients: 127 (79%) females and 33 (21%) males. Median age was 70 years in females and 74 in males. Thirty cases (19% of 159) had renal stones and 47 (37.3% of 126) had osteoporosis. Eighty-one cases (51%) received PTX. Logistic regression analysis showed that higher calcium levels (odds ratio (OR) = 73.991; p < 0.001), peak PTH (OR = 1.023; p = 0.025), peak alkaline phosphatase (OR = 0.985, p < 0.001), lower age (OR = 0.985, p < 0.001) and male gender (OR = 0.209, p < 0.002) as statistically significant predictors for patients receiving PTX. Higher age at diagnosis of PHPT was associated with increased risk of co-existent hypertension (OR = 10.904, p = 0.001) and fractures (OR = 1.067, p = 0.004). Higher peak calcium concentration was an independent predictor of acute kidney injury (OR = 9.631, p = 0.011). PTX cured 76 cases (94%) with only 7 (9%) postoperative complications. Twenty-four cases (15%) died from the entire cohort (only one from PTX group) during a median follow-up period of 3.6 years (interquartile range = 1.5).

CONCLUSIONS

PTX treatment is associated with cure of disease in patients with PHPT with acceptable risk of complications. Improvements in diagnostic work-up and follow-up care should improve the morbidity from PHPT.

[Imaging of parathyroid adenomas with F‑18 choline PET-CT]

BACKGROUND

Ultrasound and sestamibi scintigraphy are the recommended standard procedures for initial diagnosis in primary hyperparathyroidism (pHPT). Recently, F‑18 choline positron emission tomography computed tomography (choline PET/CT) has been shown promising results for the diagnostic work up of primary hyperparathyroidism (pHPT) suggesting superiority over conventional scintigraphy using Tc99m sestamibi based protocols using planar dual-phase imaging, SPECT or SPECT/CT.

METHODS

This review presents the results of F‑18 choline PET/CT on the basis of a literature search using the keywords "primary hyperparathyroidism and choline", "primary hyperparathyroidism and PET", "parathyroid adenoma and choline" und "parathyroid adenoma and PET".

RESULTS

6 studies were identified dealing with the diagnostic impact of choline PET/CT. The studies included 5 to 151 patients. Localization of single gland adenomas can be achieved with choline PET/CT in 80 up to 96% of cases. A high sensitivity and accuracy of choline PET/CT imaging is documented even in cases of repeated surgery for recurrent pHPT, in coexistant nodular goiter or in the detection of adenoma in atypical localization.

CONCLUSIONS

Using choline PET/CT parathyroid adenoma and probably parathyroid hyperplasia can be exactly localized in most patients with pHPT. Thus, a minimal-invasive surgical procedure is feasible with decreased risk of complications but high success rate in terms of biochemical cure. The diagnostic accuracy in multiglandular disease remains to be established.

Presentation, diagnostic assessment and surgical outcomes in primary hyperparathyroidism: a single centre's experience

OBJECTIVE

Primary hyperparathyroidism (PHPT) is a common reason for referral to endocrinology but the evidence base guiding assessment is limited. We evaluated the clinical presentation, assessment and subsequent management in PHPT.

DESIGN

Retrospective cohort study.

PATIENTS

PHPT assessed between 2006 - 2014 (n = 611) in a university hospital.

MEASUREMENTS

Symptoms, clinical features, biochemistry, neck radiology and surgical outcomes.

RESULTS

Fatigue (23.8%), polyuria (15.6%) and polydipsia (14.9%) were associated with PHPT biochemistry. Bone fracture was present in 16.4% but was not associated with biochemistry. A history of nephrolithiasis (10.0%) was associated only with younger age (P = 0.006) and male gender (P = 0.037). Thiazide diuretic discontinuation was not associated with any subsequent change in calcium (P = 0.514). Urine calcium creatinine clearance ratio (CCCR) was <0.01 in 18.2% of patients with confirmed PHPT. Older age (P < 0.001) and lower PTH (P = 0.043) were associated with failure to locate an adenoma on ultrasound (44.0% of scans). When an adenoma was identified on ultrasound the lateralization was correct in 94.5%. Non-curative surgery occurred in 8.2% and was greater in those requiring more than one neck imaging modality (OR 2.42, P = 0.035).

CONCLUSIONS

Clinical features associated with PHPT are not strongly related to biochemistry. Thiazide cessation does not appear to attenuate hypercalcaemia. PHPT remains the likeliest diagnosis in the presence of low CCCR. Ultrasound is highly discriminant when an adenoma is identified but surgical failure is more likely when more than one imaging modality is required.

Cardiovascular manifestations of primary hyperparathyroidism: a narrative review

Data on cardiovascular disease in primary hyperparathyroidism (PHPT) are controversial; indeed, at present, cardiovascular involvement is not included among the criteria needed for parathyroidectomy. Aim of this narrative review is to analyze the available literature in an effort to better characterize cardiovascular involvement in PHPT. Due to physiological effects of both parathyroid hormone (PTH) and calcium on cardiomyocyte, cardiac conduction system, smooth vascular, endothelial and pancreatic beta cells, a number of data have been published regarding associations between symptomatic and mild PHPT with hypertension, arrhythmias, endothelial dysfunction (an early marker of atherosclerosis), glucose metabolism impairment and metabolic syndrome. However, the results, mainly derived from observational studies, are inconsistent. Furthermore, parathyroidectomy resulted in conflicting outcomes, which may be linked to several potential biases. In particular, differences in the methods utilized for excluding confounding co-existing cardiovascular risk factors together with differences in patient characteristics, with varying degrees of hypercalcemia, may have contributed to these discrepancies. The only meta-analysis carried out in PHPT patients, revealed a positive effect of parathyroidectomy on left ventricular mass index (a predictor of cardiovascular mortality) and more importantly, that the highest pre-operative PTH levels were associated with the greatest improvements. In normocalcemic PHPT, it has been demonstrated that cardiovascular risk factors are almost similar compared to hypercalcemic PHPT, thus strengthening the role of PTH in the cardiovascular involvement. Long-term longitudinal randomized trials are needed to determine the impact of parathyroidectomy on cardiovascular diseases and mortality in PHPT.

Primary Hyperparathyroidism: Effects on Bone Health

Primary hyperparathyroidism (PHPT) is the most common cause of chronic hypercalcemia. With the advent of routine calcium screening, the classic presentation of renal and osseous symptoms has been largely replaced with mild, asymptomatic disease. In hypercalcemia caused by PHPT, serum parathyroid hormone levels are either high, or inappropriately normal. A single-gland adenoma is responsible for 80% of PHPT cases. Less frequent causes include 4-gland hyperplasia and parathyroid carcinoma. Diminished bone mineral density and nephrolithiasis are the major current clinical sequelae. Parathyroidectomy is the only definitive treatment for PHPT, and in experienced hands, cure rates approach 98%.

Primary hyperparathyroidism: review and recommendations on evaluation, diagnosis, and management. A Canadian and international consensus

The purpose of this review is to assess the most recent evidence in the management of primary hyperparathyroidism (PHPT) and provide updated recommendations for its evaluation, diagnosis and treatment. A Medline search of "Hyperparathyroidism. Primary" was conducted and the literature with the highest levels of evidence were reviewed and used to formulate recommendations. PHPT is a common endocrine disorder usually discovered by routine biochemical screening. PHPT is defined as hypercalcemia with increased or inappropriately normal plasma parathyroid hormone (PTH). It is most commonly seen after the age of 50 years, with women predominating by three to fourfold. In countries with routine multichannel screening, PHPT is identified earlier and may be asymptomatic. Where biochemical testing is not routine, PHPT is more likely to present with skeletal complications, or nephrolithiasis. Parathyroidectomy (PTx) is indicated for those with symptomatic disease. For asymptomatic patients, recent guidelines have recommended criteria for surgery, however PTx can also be considered in those who do not meet criteria, and prefer surgery. Non-surgical therapies are available when surgery is not appropriate. This review presents the current state of the art in the diagnosis and management of PHPT and updates the Canadian Position paper on PHPT. An overview of the impact of PHPT on the skeleton and other target organs is presented with international consensus. Differences in the international presentation of this condition are also summarized.

MECHANISMS IN ENDOCRINOLOGY: Kidney involvement in patients with primary hyperparathyroidism: an update on clinical and molecular aspects

Primary hyperparathyroidism (PHPT) is the third most common endocrine disease. Kidney is a target of both chronic elevated PTH and calcium in PHPT. The classic PHPT complications of symptomatic kidney stones and nephrocalcinosis have become rare and the PHPT current presentation is asymptomatic with uncertain and long-lasting progression. Nonetheless, the routine use of imaging and of biochemical determinations have revealed the frequent occurrence of asymptomatic kidney stones, hypercalciuria and reduced kidney function in asymptomatic PHPT patients. Though the pathogenesis is far from being elucidated, PHPT is associated with reduced renal function, in terms of estimated glomerular filtration rate, and related increased morbidity and mortality. In the last decade, the effort of the Kidney Disease: Improving Global Outcomes (KDIGO) panel of experts highlighted that even mild reduction of kidney function is associated with increased risk of cardiovascular disease. These considerations provided the basis for the Fourth Workshop recommendations of a more extensive diagnostic workout about kidney features and of wider criteria for parathyroid surgery including asymptomatic kidney disease. Moreover, kidney involvement in PHPT is likely to be affected by variants of genes coding the key molecules regulating the calcium and ions renal handling; these features might have clinical relevance and should be considered both during diagnostic workout and follow-up. Finally, the effects of parathyroid surgery and of medical treatment on kidney involvement of PHPT are reviewed.

Impaired endothelial function in patients with mild primary hyperparathyroidism improves after parathyroidectomy

BACKGROUND

Primary hyperparathyroidism (PHPT) is associated with cardiovascular morbidity; however, data on the reversibility of cardiovascular disease in mild primary hyperparathyroidism are conflicting. The aim of this study was to assess endothelial function in patients with mild PHPT before and after parathyroidectomy (Ptx).

METHODS

We prospectively evaluated 53 patients with mild PHPT (Group 1; 45 women, eight men; aged 52 ± 3·1 years) and 46 healthy control subjects (Group 2; 38 women, eight men; aged 46 ± 9·5 years). Endothelial function was measured as flow-mediated dilation (FMD) and carotid intima-media thickness (CIMT) using Doppler ultrasonography. Patients with diabetes mellitus, coronary heart disease, impaired renal function, hyperthyroidism, hypothyroidism and a history of smoking were excluded from the study. Patients were studied at baseline and 6-12 months after the first evaluation.

RESULTS

There were no differences with respect to age, gender and BMI between the two groups. Hypertension prevalence was three times higher in group 1 than in controls. % FMD was lower in group 1 than in group 2 (2·6 ± 1·2 vs 14·8 ± 9·6, P < 0·001). CIMT was higher in patients with PHPT than controls (0·69 ± 0·18 vs 0·61 ± 0·12, P = 0·045). This significance remained when hypertensive patients were excluded from the analysis. While FMD and CIMT improved significantly after Ptx, there were no differences in mild PHPT patients who followed without parathyroidectomy.

CONCLUSION

FMD and CIMT are impaired in patients with mild PHPT compared to controls and improved significantly after a successful Ptx. Ptx improves endothelial function in patients with mild PHPT that may lead to decreased cardiovascular morbidity and mortality.

Novel inflammatory biomarkers in primary hyperparathyroidism

OBJECTIVE

Primary hyperparathyroidism (PHPT) has been associated with low-grade inflammation and increased risk of cardiovascular disease (CVD). The aim of the study was to investigate systemic levels of pro-inflammatory proteins that previously have not been examined in patients with PHPT. The selection of the pro-inflammatory biomarkers included in this study, MMP9, S100A4, S100A8/A9 and the receptors sCD14 and RAGE, was based on a previous microarray screen of mRNAs in adipose tissue from PHPT patients.

DESIGN

A prospective study was conducted on a total of 57 patients with PHPT and a control group of 20 healthy blood donors.

METHODS

PHPT patients with normalisation of serum calcium levels after parathyroidectomy were followed for 6 months. Forty-two patients participated in the longitudinal study, in which blood samples were taken at inclusion, and 1, 3 and 6 months after surgery.

RESULTS

We observed increased serum levels of MMP9 (P=0.029), S100A4 (P<0.001) and sCD14 (P=0.002) in the 57 patients with PHPT compared to the control-group. During 6 months of follow up, S100A4 (P=0.022) and sCD14 (0.002) decreased significantly, while serum levels of MMP9 increased (P=0.025).

CONCLUSIONS

The results demonstrate an increased inflammatory response in PHPT patients shown by elevated MMP9, S100A4 and sCD14 at inclusion. During the 6 months of follow-up, MMP9 increased further, possibly due to the tissue repair process after parathyroidectomy. S100A4 and sCD14 decreased after surgery demonstrating a partial reversal of the systemic inflammation.

[Localization of parathyroid adenomas with C11-methionine PET-CT]

BACKGROUND AND OBJECTIVES

In primary hyperparathyroidism (pHPT) preoperative localization of parathyroid adenomas enables focussed unilateral parathyroidectomy. Ultrasound and sestamibi scintigraphy are the recommended standard procedures for primary diagnostics of pHPT and C-11 methionine positron emission tomography computed tomography (Met-PET/CT) is the latest technique for localization of hyperfunctioning parathyroid glands.

METHODS

This review presents the results of Met-PET/CT on the basis of a selective literature search using the keywords "primary hyperparathyroidism and methionine", "primary hyperparathyroidism and PET", "parathyroid adenomas and methionine" and "parathyroid adenomas and PET".

RESULTS

Localization of single gland adenomas can be achieved with Met-PET/CT in 79-91 % of cases. The advantages of this procedure are a high sensitivity even in operations for recurrencies or concomitant thyroid nodules and an accurate detection even with atypical localizations. In multiglandular disease a localization of more than one hyperfunctioning gland remains difficult. Potential limitations of the method include the restricted availability and the relatively high costs of Met-PET/CT.

CONCLUSIONS

Using Met-PET/CT hyperfunctioning parathyroid glands can be exactly localized in most patients with pHPT. Indications for this procedure are mostly when preoperative standard tests are negative and in parathyroid surgery for recurrencies.

Mortality associated with primary hyperparathyroidism

561 patients with primary hyperparathyroidism were followed between 1961 and 1994. Relative survival was compared to that of the Australian population studied during the same time interval. Mortality was significantly greater in the hyperparathyroid population (P<0.001). Mortality was not greater in the patients with serum calcium levels >3.00 mmol/L compared to those with a serum calcium levels <3.00 mmol/L. 113 patients did not have parathyroid surgery. Their relative survival was not significantly different from those who had surgery but their mean serum calcium and parathyroid hormone (PTH) levels were significantly lower than those who had surgery. A re-analysis of the 453 patients followed between 1972 and 2011 was carried out and a 20-year survival analysis made of those diagnosed between 1972 and 1981 and those diagnosed between 1982 and 1991. The latter group had significantly worse relative mortality than the former group (P<0.001) but was significantly older at the time of diagnosis (56.94 ± 14.83 vs 52.01 ± 13.58, P<0.001). The serum calcium and serum PTH levels were not significantly different between these two groups.

Primary hyperparathyroidism and vitamin D deficiency

Primary hyperparathyroidism (PHPT) and vitamin D (VD) deficiency are frequent conditions due to the widespread application of assays for calcium and VD. PHPT presentation is dominated by diversity in its expression and the current predominance of asymptomatic forms. VD, which plays a major role in calcium and phosphate homeostasis, is also involved in many physiological processes in this disease, such as lipid and glucose metabolism, and in the signalling pathways and functioning of many cell types. The bone and cardiometabolic complications described in PHPT are exacerbated by vitamin D deficiency, the prevalence of which varies according to many parameters (environment, skin pigmentation, associated chronic diseases, liver and kidney function, assay kit used, etc.). In response to this observation, experts in field from medical societies validated the indication for systematic assay of VD occurring with PHPT and the need for replacement in case of deficiency. Several epidemiological studies have confirmed that replacement with natural vitamin D is well tolerated and safe in subjects with PHPT and VD deficiency. This supplementation reduces hyperparathormonemia, does not have symptomatic effects on calciuria, and especially improves the bone and functional condition of patients.

Current issues in the presentation of asymptomatic primary hyperparathyroidism: proceedings of the Fourth International Workshop

OBJECTIVE

This report summarizes data on traditional and nontraditional manifestations of primary hyperparathyroidism (PHPT) that have been published since the last International Workshop on PHPT.

PARTICIPANTS

This subgroup was constituted by the Steering Committee to address key questions related to the presentation of PHPT. Consensus was established at a closed meeting of the Expert Panel that followed.

EVIDENCE

Data from the 5-year period between 2008 and 2013 were presented and discussed to determine whether they support changes in recommendations for surgery or nonsurgical follow-up.

CONSENSUS PROCESS

Questions were developed by the International Task Force on PHPT. A comprehensive literature search for relevant studies was undertaken. After extensive review and discussion, the subgroup came to agreement on what changes in the recommendations for surgery or nonsurgical follow-up of asymptomatic PHPT should be made to the Expert Panel.

CONCLUSIONS

1) There are limited new data available on the natural history of asymptomatic PHPT. Although recognition of normocalcemic PHPT (normal serum calcium with elevated PTH concentrations; no secondary cause for hyperparathyroidism) is increasing, data on the clinical presentation and natural history of this phenotype are limited. 2) Although there are geographic differences in the predominant phenotypes of PHPT (symptomatic, asymptomatic, normocalcemic), they do not justify geography-specific management guidelines. 3) Recent data using newer, higher resolution imaging and analytic methods have revealed that in asymptomatic PHPT, both trabecular bone and cortical bone are affected. 4) Clinically silent nephrolithiasis and nephrocalcinosis can be detected by renal imaging and should be listed as a new criterion for surgery. 5) Current data do not support a cardiovascular evaluation or surgery for the purpose of improving cardiovascular markers, anatomical or functional abnormalities. 6) Some patients with mild PHPT have neuropsychological complaints and cognitive abnormalities, and some of these patients may benefit from surgical intervention. However, it is not possible at this time to predict which patients with neuropsychological complaints or cognitive issues will improve after successful parathyroid surgery.

Sporadic primary hyperparathyroidism: medical and surgical updates

This review discusses recent findings on the clinical presentation, evaluation, medical and surgical management of primary hyperparathyroidism. Medical management includes the use of cinacalcet and bisphosphonates for bone loss and correction of vitamin D deficiency. Surgical updates reviewed recent studies on the preoperative localization of the disease, specifically, sestamibi scans, 4DCT and MRI. Focused parathyroidectomy continues to be the preferred surgical approach for a select group of patients, guided by intraoperative use of PTH and new technology, such as endoscopic and robotic platforms; however, there appears to be no difference in long-term success compared to the traditional approach.

Subclinical and asymptomatic parathyroid disease: implications of emerging data

Primary hyperparathyroidism, a disorder in which there is a tendency for hypercalcaemia caused by autonomous overproduction of parathyroid hormone, is common, especially in postmenopausal women. Although parathyroidectomy is indicated for symptomatic patients, most individuals with the disorder are asymptomatic and without classic complications, such as renal stones and osteoporosis, at diagnosis. Consensus guidelines suggest which individuals might be suitable for medical follow-up rather than parathyroidectomy, but there are no long-term randomised controlled trials to support the safety of medical surveillance, and some patients progress with time. Data from observational studies suggest that cardiovascular morbidity and mortality are increased in patients with primary hyperparathyroidism, and might be predicted by parathyroid hormone concentrations, even in individuals with asymptomatic primary hyperparathyroidism. Whether parathyroidectomy improves cardiovascular outcomes in patients with asymptomatic primary hyperparathyroidism is unproven, but data suggest that surgery decreases fracture risk and might improve neuropsychological symptoms. Studies also show that patients with normocalcaemic (subclinical) hyperparathyroidism and hypoparathyroidism have a low risk of progression to overt disease, but their long-term risks are not defined. In this Review, we explore the increasing range of asymptomatic parathyroid disorders, focusing on current evidence about their natural history and potential complications, with a particular emphasis on primary hyperparathyroidism.