The efficacy and safety of cinacalcet in primary hyperparathyroidism: a systematic review and meta-analysis of randomized controlled trials and cohort studies

Efficacy of Oral Cinacalcet in Non-PTH Nonmalignant Hypercalcemia from Excess 1,25-Dihydroxyvitamin D

Elevated 1,25-dihydroxyvitamin D (1,25(OH)2D) is a rare cause of non-parathyroid hormone (PTH)-mediated hypercalcemia seen in granulomatous disease, malignancy (most often lymphoma), or genetic mutations. Therapeutic options are limited. We report the case of a 67-year-old White man with nonmalignant, nongranulomatous, 1,25(OH)2D-mediated hypercalcemia treated successfully with cinacalcet. At presentation, he had hypercalcemia, hypercalciuria with recurrent nephrolithiasis, low PTH, elevated 1,25(OH)2D, and normal 25-hydroxyvitamin D. The 1,25(OH)2D levels were inappropriate in the setting of hypercalcemia with low PTH. Evaluations for sarcoidosis, tuberculosis, and malignancy were negative. Genetic testing showed biallelic variants in the CYP24A1 gene. Cinacalcet was trialed and showed normalization of calcium levels. On cinacalcet, biochemical indices showed a slight increase in 1,25(OH)2D and 24-hour urine calcium and mild decrease in PTH. He briefly experienced symptomatic hypocalcemia that resolved after reducing cinacalcet dose. Due to limited symptomatic benefit, he opted to stop cinacalcet. Additional follow-up showed intermittently elevated serum calcium levels after stopping cinacalcet, most recently 10.3 mg/dL. Cinacalcet may be a therapeutic option in nonmalignant, 1,25(OH)2D-mediated hypercalcemia. Further study is necessary to confirm efficacy, understand risks and benefits, and elucidate mechanism(s) of action.

Cinacalcet Reverses Short QT Interval in Familial Hypocalciuric Hypercalcemia Type 1

CONTEXT

Familial hypocalciuric hypercalcemia type 1 (FHH-1) defines an autosomal dominant disease, related to mutations in the CASR gene, with mild hypercalcemia in most cases. Cases of FHH-1 with a short QT interval have not been reported to date.

OBJECTIVE

Three family members presented with FHH-1 and short QT interval (<360 ms), a condition that could lead to cardiac arrhythmias, and the effects of cinacalcet, an allosteric modulator of the CaSR, in rectifying the abnormal sensitivity of the mutant CaSR and in correcting the short QT interval were determined.

METHODS

CASR mutational analysis was performed by next-generation sequencing and functional consequences of the identified CaSR variant (p.Ile555Thr), and effects of cinacalcet were assessed in HEK293 cells expressing wild-type and variant CaSRs. A cinacalcet test consisting of administration of 30 mg cinacalcet (8 Am) followed by hourly measurement of serum calcium, phosphate, and parathyroid hormone during 8 hours and an electrocardiogram was performed.

RESULTS

The CaSR variant (p.Ile555Thr) was confirmed in all 3 FHH-1 patients and was shown to be associated with a loss of function that was ameliorated by cinacalcet. Cinacalcet decreased parathyroid hormone by >50% within two hours, and decreases in serum calcium and increases in serum phosphate occurred within 8 hours, with rectification of the QT interval, which remained normal after 3 months of cinacalcet treatment.

CONCLUSION

Our results indicate that FHH-1 patients should be assessed for a short QT interval and a cinacalcet test used to select patients who are likely to benefit from this treatment.

Morbidity Associated With Primary Hyperparathyroidism-A Population-based Study With a Subanalysis on Vitamin D

CONTEXT

Primary hyperparathyroidism (PHPT) is associated with increased risk of morbidity and death, and vitamin D levels are a potentially confounding variable.

OBJECTIVE

The aim of this study was to assess morbidity and mortality associated with primary hyperparathyroidism (PHPT).

METHODS

In this population-based retrospective matched cohort study, data linkage of biochemistry, hospital admissions, prescribing, imaging, pathology, and deaths was used to identify patients across the region of Tayside, Scotland, who had PHPT from 1997 to 2019. Cox proportional hazards models and hazards ratios (HR) were used to explore the relationship between exposure to PHPT and several clinical outcomes. Comparisons were made with an age- and gender-matched cohort.

RESULTS

In 11 616 people with PHPT (66.8% female), with a mean follow-up period of 8.8 years, there was an adjusted HR of death of 2.05 (95% CI, 1.97-2.13) for those exposed to PHPT. There was also an increased risk of cardiovascular disease (HR = 1.34; 95% CI, 1.24-1.45), cerebrovascular disease (HR = 1.29; 95% CI, 1.15-1.45), diabetes (HR = 1.39; 95% CI, 1.26-1.54), renal stones (HR = 3.02; 95% CI, 2.19-4.17) and osteoporosis (HR = 1.31; 95% CI, 1.16-1.49). Following adjustment for serum vitamin D concentrations (n = 2748), increased risks for death, diabetes, renal stones, and osteoporosis persisted, but not for cardiovascular or cerebrovascular disease.

CONCLUSION

In a large population-based study, PHPT was associated with death, diabetes, renal stones, and osteoporosis, independent of serum vitamin D concentration.

Neuroendocrine Parathyroid Tumors: Quality of Life in Patients with Primary Hyperparathyroidism

Tumors of the parathyroid glands, when associated with PTH (parathyroid hormone) excess, display a large area of complications; in addition to the classical clinical picture of primary hyperparathyroidism (PHP), a complex panel of other symptoms/signs can be identified, including memory and cognitive impairment, chronic asthenia/fatigue, reduced muscle functionality, depressive mood, non-specific bone pain, and loss of sleep quality. The perception of quality of life (QoL) can be supplementarily enhanced by their progressive onset, which makes many patients not be fully aware of them. Their improvement was reported very early after parathyroidectomy (PTx), yet the level of statistical evidence does not qualify these non-classical elements as standalone indications for PTx. Our objective is introducing an up-to-date on QoL scores with regards to the patients diagnosed with PHP, particularly taking into consideration PHP management from baseline to post-operatory outcome, including in cases with multiple endocrine neoplasia. This is a narrative review of literature. We revised full-length papers published in English through PubMed research conducted between January 2018 and May 2023 by using the key words "quality of life" and "primary hyperparathyroidism". We particularly looked at data on self-reported QoL (through questionnaires). We excluded from the search the studies focused on non-PTH related hypercalcemia, secondary, and/or renal/tertiary hyperparathyroidism, and vitamin D supplementation. Overall, we identified 76 papers and selected for the final analysis 16 original studies on QoL and PHP (a total of 1327 subjects diagnosed with syndromic and non-syndromic PHP). The studies with the largest number of individuals were of 92, 104, 110, 134, 159, as well as 191. A few cohorts (n = 5) were of small size (between 20 and 40 patients in each of them). Concerning the study design, except for 2 papers, all the mentioned studies provided longitudinal information, particularly the timeframe from baseline (before PTx) and after surgery. The post-operatory follow-up was of 3-6 months, but mostly between 1 and 3 years (maximum a decade of surveillance). The age of the patients varies between medians of 56, 62, 64, and 68 years. Most frequent questionnaires were SF-36, PHPQoL, and PAS. Despite not being unanimously similar, an overall reduced score of QoL in patients with PHP versus controls was registered, as well as general improvement following PTx. Variations of QoL results might have a multifactorial background from different comorbidities, studied populations, technical aspects of collecting the data, etc. QoL scores in PHP represents a complex heterogeneous picture, from their correlation with clinical features and lab assays (e.g., the level of serum calcium), the associated comorbidities (such as multiple endocrine neoplasia syndromes), up to the assessment of the QoL improvement after parathyroidectomy (PTx). While current studies do not unanimously agree on each QoL domain, the assessment of QoL might represent a supplementary argument to consider when deciding for PTx, especially in asymptomatic cases and in patients who do not fit into well-known categories of surgery candidates, according to current guidelines, thus assessing QoL in PHP is part of a current research gap. QoL evaluation in PHP remains an open issue, towards which awareness should be cultivated by both endocrinologists and surgeons. The introduction of a routine evaluation of the QoL scores in patients, as well as the selection of the most appropriate questionnaire(s), represents an open chapter thus awareness in mandatory.

[Special features of the diagnostics and treatment of hereditary primary hyperparathyroidism]

Between 2% and 10% of patients with primary hyperparathyroidism (pHPT) are diagnosed with hereditary forms of primary hyperparathyroidism (hpHPT). They are more prevalent in younger patients before the age of 40 years, in patients with persistence or recurrence of pHPT and pHPT patients with multi-glandular disease (MGD). The various forms of hpHPT diseases can be classified into four syndromes, i.e., hpHPT associated with diseases of other organ systems, and four diseases that are confined to the parathyroid glands. Approximately 40% of patients with hpHPT suffer from multiple endocrine neoplasia type 1 (MEN-1) or show germline mutations of the MEN‑1 gene. Currently, germline mutations that lead to a specific diagnosis in patients with hpHPT have currently been described in 13 different genes, which enables a clear diagnosis of the disease; however, a clear genotype-phenotype correlation does not exist, even though the complete loss of a coded protein (e.g. due to frame-shift mutations in the calcium sensing receptor, CASR) often leads to more severe clinical consequences than merely a reduced function of the protein (e.g. due to point mutation). As the various hpHPT diseases require different treatment approaches, which do not correspond to that of sporadic pHPT, a clear definition of the specific form of hpHPT must always be strived for. Therefore, before surgery of a pHPT with clinical, imaging or biochemical suspicion of hpHPT, genetic proof or exclusion of hpHPT is necessary. The differentiated treatment approach for hpHTP can only be defined by taking the clinical and diagnostic results of all the abovenamed findings into account.

Management of Primary Hyperparathyroidism

Since the last international guidelines were published in 2014 on the evaluation and management of primary hyperparathyroidism (PHPT), new information has become available with regard to evaluation, diagnosis, epidemiology, genetics, classical and nonclassical manifestations, surgical and nonsurgical approaches, and natural history. To provide the most current summary of these developments, an international group, consisting of over 50 experts in these various aspects of PHPT, was convened. This paper provides the results of the task force that was assigned to review the information on the management of PHPT. For this task force on the management of PHPT, two questions were the subject of systematic reviews using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) methodology. The full report addressing surgical and nonsurgical management of PHPT, utilizing the GRADE methodology, is published separately in this series. In this report, we summarize the results of that methodological review and expand them to encompass a much larger body of new knowledge that did not specifically fit the criteria of the GRADE methodology. Together, both the systematic and narrative reviews of the literature, summarized in this paper, give the most complete information available to date. A panel of experts then considered the last set of international guidelines in light of the newer data and assessed the need for their revision. This report provides the evidentiary background to the guidelines report. In that report, evidence from all task forces is synthesized into a summary statement and revised guidelines for the evaluation and management of PHPT. © 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).

The Efficacy and Safety of Medical and Surgical Therapy in Patients With Primary Hyperparathyroidism: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Both medical and surgical therapy represent potential management options for patients with asymptomatic primary hyperparathyroidism (PHPT). Because uncertainty remains regarding both medical and surgical therapy, this systematic review addresses the efficacy and safety of medical therapy in asymptomatic patients or symptomatic patients who decline surgery and surgery in asymptomatic patients. We searched Medline, Embase, Cochrane Central Register of Controlled Trials, and PubMed from inception to December 2020, and included randomized controlled trials in patients with PHPT that compared nonsurgical management with medical therapy versus without medical therapy and surgery versus no surgery in patients with asymptomatic PHPT. For surgical complications we included observational studies. Paired reviewers addressed eligibility, assessed risk of bias, and abstracted data for patient-important outcomes. We conducted random-effects meta-analyses to pool relative risks and mean differences with 95% confidence intervals and used Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) to assess quality of evidence for each outcome. For medical therapy, 11 trials reported in 12 publications including 438 patients proved eligible: three addressed alendronate, one denosumab, three cinacalcet, two vitamin D, and two estrogen therapy. Alendronate, denosumab, vitamin D, and estrogen therapy all increased bone density. Cinacalcet probably reduced serum calcium and parathyroid hormone (PTH) levels. Cinacalcet and vitamin D may have a small or no increase in overall adverse events. Very-low-quality evidence raised the possibility of an increase in serious adverse events with alendronate and denosumab. The trials also provided low-quality evidence for increased bleeding and mastalgia with estrogen therapy. For surgery, six trials presented in 12 reports including 441 patients proved eligible. Surgery achieved biochemical cure in 96.1% (high quality). We found no convincing evidence supporting an impact of surgery on fracture, quality of life, occurrence of kidney stones, and renal function, but the evidence proved low or very low quality. Surgery was associated with an increase in bone mineral density. For patients with symptomatic and asymptomatic PHPT, who are not candidates for parathyroid surgery, cinacalcet probably reduced serum calcium and PTH levels; anti-resorptives increased bone density. For patients with asymptomatic PHPT, surgery usually achieves biochemical cure. These results can help to inform patients and clinicians regarding use of medical therapy and surgery in PHPT. © 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).

Hypercalcemia: A Review

IMPORTANCE

Hypercalcemia affects approximately 1% of the worldwide population. Mild hypercalcemia, defined as total calcium of less than 12 mg/dL (<3 mmol/L) or ionized calcium of 5.6 to 8.0 mg/dL (1.4-2 mmol/L), is usually asymptomatic but may be associated with constitutional symptoms such as fatigue and constipation in approximately 20% of people. Hypercalcemia that is severe, defined as total calcium of 14 mg/dL or greater (>3.5 mmol/L) or ionized calcium of 10 mg/dL or greater (≥2.5 mmol/L) or that develops rapidly over days to weeks, can cause nausea, vomiting, dehydration, confusion, somnolence, and coma.

OBSERVATIONS

Approximately 90% of people with hypercalcemia have primary hyperparathyroidism (PHPT) or malignancy. Additional causes of hypercalcemia include granulomatous disease such as sarcoidosis, endocrinopathies such as thyroid disease, immobilization, genetic disorders, and medications such as thiazide diuretics and supplements such as calcium, vitamin D, or vitamin A. Hypercalcemia has been associated with sodium-glucose cotransporter 2 protein inhibitors, immune checkpoint inhibitors, denosumab discontinuation, SARS-CoV-2, ketogenic diets, and extreme exercise, but these account for less than 1% of causes. Serum intact parathyroid hormone (PTH), the most important initial test to evaluate hypercalcemia, distinguishes PTH-dependent from PTH-independent causes. In a patient with hypercalcemia, an elevated or normal PTH concentration is consistent with PHPT, while a suppressed PTH level (<20 pg/mL depending on assay) indicates another cause. Mild hypercalcemia usually does not need acute intervention. If due to PHPT, parathyroidectomy may be considered depending on age, serum calcium level, and kidney or skeletal involvement. In patients older than 50 years with serum calcium levels less than 1 mg above the upper normal limit and no evidence of skeletal or kidney disease, observation may be appropriate. Initial therapy of symptomatic or severe hypercalcemia consists of hydration and intravenous bisphosphonates, such as zoledronic acid or pamidronate. In patients with kidney failure, denosumab and dialysis may be indicated. Glucocorticoids may be used as primary treatment when hypercalcemia is due to excessive intestinal calcium absorption (vitamin D intoxication, granulomatous disorders, some lymphomas). Treatment reduces serum calcium and improves symptoms, at least transiently. The underlying cause of hypercalcemia should be identified and treated. The prognosis for asymptomatic PHPT is excellent with either medical or surgical management. Hypercalcemia of malignancy is associated with poor survival.

CONCLUSIONS AND RELEVANCE

Mild hypercalcemia is typically asymptomatic, while severe hypercalcemia is associated with nausea, vomiting, dehydration, confusion, somnolence, and coma. Asymptomatic hypercalcemia due to primary hyperparathyroidism is managed with parathyroidectomy or observation with monitoring, while severe hypercalcemia is typically treated with hydration and intravenous bisphosphonates.