Clinical phenotypes of primary hyperparathyroidism in hospitalized patients who underwent parathyroidectomy

Risk of Gallstone Disease in Primary Hyperparathyroidism: A Systematic Review and Meta-analysis

OBJECTIVE

Apart from renal stones, primary hyperparathyroidism (PHPT) has been linked to the occurrence of gallstone disease (GSD). Nevertheless, the association is not consistent across all studies. The present systematic review and meta-analysis aims to collate the hitherto available evidence and provide a pooled estimate of the association between GSD and PHPT.

METHODS

PubMed/MEDLINE, Embase, and Web of Science databases were systematically searched from inception till May 10, 2023 for observational studies reporting the prevalence of GSD (in terms of absolute numbers) in patients with PHPT. The pooled prevalence of GSD and odds ratio with 95% CI of the occurrence of GSD in patients with PHPT as compared to age- and sex-matched controls were calculated. Subgroup analysis was performed based on patient ethnicity (Indian/Caucasian). Statistical analysis was carried out using R version 4.2.2. Random-effects model with Hartung-Knapp adjustment was used for analyses.

RESULTS

A total of 7 observational studies were included, pooling data from 15 949 patients with PHPT. The pooled prevalence of GSD in patients with PHPT was 16% (95% CI: 7%, 25%, I2 = 99%), being 13% (95% CI: 0%, 66%, I2 = 76%) in Indians, and 17% (95% CI: 4%, 31%, I2 = 99%) in Caucasians. Data consolidated from 3 studies showed that the pooled odds ratio of occurrence of GSD in patients with PHPT compared to controls was 1.77 (95% CI: 1.60, 1.97, P < .001, I2 = 0%).

CONCLUSIONS

GSD is more prevalent in patients with PHPT than in the general population. Thus, PHPT may be considered an additional risk factor for GSD.

Hypomagnesemia may be associated with symptomatic disease in patients with primary hyperparathyroidism

AIM

Magnesium (Mg) homeostasis is closely related to calcium (Ca) metabolism. Hypercalcemia inhibits the reabsorption of Mg from the kidneys, leading to hypomagnesemia. Therefore, patients with primary hyperparathyroidism (PHPT) are predisposed to hypomagnesemia. However, there are few studies on the clinical significance of hypomagnesemia in PHPT. The aim of this study was to retrospectively evaluate the association of hypomagnesemia with the clinical outcomes of PHPT.

MATERIALS AND METHODS

A retrospective evaluation was made of the data of 538 consecutive patients (478 females, 60 males) diagnosed with PHPT in our center.

RESULTS

The mean age of the study population was 56.5 ± 11.66 years. The mean serum Mg level was 2 ± 0.26 mg/dl. Asymptomatic disease was present in 241 (44%) patients. Symptomatic patients with osteoporosis, Ca level ≥11.2 mg/dl, and estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 had lower levels of Mg (p < 0.05). Hypomagnesemia was detected in 129 of 538 patients (23.9%). The patients with hypomagnesemia had a higher rate of symptomatic disease (80% vs. 48%, p < 0.0001). The serum parathormone (PTH) level was found to be higher in patients with hypomagnesemia and the lumbar and femur T-scores and serum vitamin D levels were lower (p < 0.05). Patients with hypomagnesemia had higher rates of kidney stones (34% vs. 21%, p = 0.003) and osteoporosis (74% vs. 32%, p < 0.001). Multivariate logistic regression analysis revealed that hypomagnesemia had a significant effect on the development of symptomatic disease (OR:6.88, CI 95%: 5.20-11.27, p < 0.001).

CONCLUSIONS

The current study results demonstrate that hypomagnesemia may be associated with a higher risk of osteoporosis and kidney stones in PHPT patients. Routine evaluation of serum Mg may predict the clinical outcomes of PHPT.

The Russian registry of primary hyperparathyroidism, latest update

Introduction

Until recently no major epidemiological research of primary hyperparathyroidism (PHPT) has been conducted in the Russian Federation, this led to the creation of the Russian online registry. The objective of this study is to estimate the clinical and biochemical profile, classical and non-classical complications, surgical intervention and medical therapy of the patients with different forms of PHPT in the Russian Federation.

Materials and methods

The cross-sectional, observational, continuous study was conducted at the Endocrinology Research Centre (Moscow). The present study explored retrospective data from 6003 patients submitted to the Registry between 12.12.2016 and 25.10.2022 from 81 regions of the Russian Federation (http://pgpt.clin-reg.ru/).

Results

The median age was 59 [60; 66] years with a female:male ratio of 11.7:1. Symptomatic PHPT was observed in 74.3% while asymptomatic form - only in 25.7% of cases. Bone pathology was the predominant clinical manifestation in 62.5% of cases (n=2293), mostly in combination with visceral complications 45.7% (n=1676). The majority of patients (63.3%) had combined visceral disorders including kidney damage in 51.8% and gastroduodenal erosions/ulcers in 32.3% of patients. Symptomatic patients were older (60 [53; 67] vs. 54 [45; 62] years, p<0.001) and had more severe biochemical alterations of calcium-phosphorus metabolism. Cardiovascular disease (СVD) was recorded in 48% of patients, among them the most frequent was arterial hypertension (up to 93.9%). A genetic test was conducted in 183 cases (suspicious for hereditary PHPT) revealing the mutations in MEN1, CDC73, RET genes in 107, 6 and 2 cases, respectively. Surgery was performed in 53.4% of patients with remission achievement in 87%, the relapse/persistence were recorded in 13% of cases. Histological examination revealed carcinoma in 4%, atypical adenoma in 2%, adenoma in 84% and hyperplasia in 11% of cases. Drug therapy was prescribed in 54.0% of cases, most often cholecalciferol.

Conclusion

The detection rate of PHPT has increased in the Russian Federation in recent years. This increase is associated with the start of online registration. However, the majority of patients remain symptomatic with significant alterations of phosphorus-calcium metabolism that indicates delayed diagnosis and requires further modifications of medical care.

Scientific Basics of Personalized Medicine: Realities and Opportunities

Modern trends in the development of health care suggest its focus on the interests of the patient and its holistic nature, as well as deep penetration into all parts of health care information technology. The driving force behind the ongoing changes, of course, are scientific achievements, the importance of which in the development of new medical technologies and the creation of innovative diagnostic devices, as well as medicines, has grown significantly in recent years. These processes provide conditions for the introduction into clinical practice of a new model of medical care-personalized medicine, based on the choice of methods of diagnosis and treatment with account for the individual characteristics of the course of the disease, as well as the patient's lifestyle. Personalized medicine technologies, which involve the creation of an appropriate, often expensive, infrastructure of omics technologies, should ultimately lead to an increase in the efficiency, quality, and, most importantly, safety of medical care. In the Russian Federation, this area is actively developing in four world-class research centers, including the Almazov National Medical Research Center. The current state and prospects of research in the field of personalized medicine are discussed in this article, prepared by the author on the basis of his scientific report at a meeting of the Presidium of the Russian Academy of Sciences.

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).

Immunohistochemical Profile of Parathyroid Tumours: A Comprehensive Review

Immunohistochemistry remains an indispensable tool in diagnostic surgical pathology. In parathyroid tumours, it has four main applications: to detect (1) loss of parafibromin; (2) other manifestations of an aberrant immunophenotype hinting towards carcinoma; (3) histogenesis of a neck mass and (4) pathogenetic events, including features of tumour microenvironment and immune landscape. Parafibromin stain is mandatory to identify the new entity of parafibromin-deficient parathyroid neoplasm, defined in the WHO classification (2022). Loss of parafibromin indicates a greater probability of malignant course and should trigger the search for inherited or somatic CDC73 mutations. Aberrant immunophenotype is characterised by a set of markers that are lost (parafibromin), down-regulated (e.g., APC protein, p27 protein, calcium-sensing receptor) or up-regulated (e.g., proliferation activity by Ki-67 exceeding 5%) in parathyroid carcinoma compared to benign parathyroid disease. Aberrant immunophenotype is not the final proof of malignancy but should prompt the search for the definitive criteria for carcinoma. Histogenetic studies can be necessary for differential diagnosis between thyroid vs. parathyroid origin of cervical or intrathyroidal mass; detection of parathyroid hormone (PTH), chromogranin A, TTF-1, calcitonin or CD56 can be helpful. Finally, immunohistochemistry is useful in pathogenetic studies due to its ability to highlight both the presence and the tissue location of certain proteins. The main markers and challenges (technological variations, heterogeneity) are discussed here in the light of the current WHO classification (2022) of parathyroid tumours.

[Primary hyperparathyreoidism - diagnostic procedures and management]

Hypercalcemia as a laboratory result is often diagnosed during evaluation for osteoporosis. Any form of hypercalcemia should be evaluated further. Owing to fluctuating calcium levels, the measurement should be repeated and corrected for elevated albumin levels by calculation or by measuring ionized calcium. In the diagnosis of primary hyperparathyroidism, measurement of parathyroid hormone, creatinine/glomerular filtration rate, phosphate, 25-OH vitamin D3 and 24-hour urine values are essential for differential diagnosis. Kidney ultrasound is used to detect nephrocalcinosis or kidney stones, and dual-energy X-ray absorptiometry (DXA) to determine bone mineral density (BMD) at the lumbar spine, femoral neck, total femur, and distal forearm. Complete cure is only possible through surgical resection of the adenoma(s). The indication for surgery is dependent on the age of the patient, existing complications, and the patient's preference. Diagnostic imaging should only be performed if surgery is planned. Typically, neck ultrasound and 99mTc MIBI scintigraphy are sufficient to localize the parathyroid adenoma. Presurgical diagnostic evaluation of the thyroid is reasonable for surgical planning. Vitamin-D deficiency should be normalized before surgery. Postsurgical calcium and vitamin-D administration will prevent postsurgical hypocalcemia and hungry-bone disease, and may optimize the outcome of BMD. Treatment of osteoporosis without fractures might not be necessary, owing to normalization of BMD several years after parathyroid surgery. The continuation of specific anti-osteoporotic treatment with bisphosphonates post-surgery did not have any advantage and hence cannot be recommended.

Serum Phosphate: A Neglected Test in the Clinical Management of Primary Hyperparathyroidism

BACKGROUND

Although the inverse correlation between serum PTH and phosphate (P) levels in patients with primary hyperparathyroidism (PHPT) is well known, the relationship between P levels and the clinical picture of the disease has not been well investigated. This was thus the aim of this paper.

PATIENTS

A total of 472 consecutive patients with PHPT attending our center were retrospectively evaluated at diagnosis.

RESULTS

P levels lower than 2.5 mg/dL (HypoP) were found in 198/472 patients (41.9%). HypoP was mild (2-2.5 mg/dL), moderate (1-1.9 mg/dL), and severe (<1 mg/dL) in 168 (84.9%), 30 (15.1%), and 0 cases, respectively. P levels were lower in males than females. Patients with more severe bone density impairment at the radial (but not the vertebral or femoral) site had P levels significantly lower than other patients. PHPT severity was worse in HypoP patients, both clinically (higher prevalence of renal stones, but not of osteoporosis) and biochemically (higher serum calcium and PTH levels). All patients in the moderate HypoP group were either symptomatic or asymptomatic reaching surgical indication according to the latest guidelines.

CONCLUSIONS

We observed a relationship between P levels and biochemical and clinical features of PHPT severity. In asymptomatic PHPT patients, even moderate HypoP is predictive of surgical indication, regardless of age and hypercalcemia severity.