Insulin sensitivity in normocalcaemic primary hyperparathyroidism

Normocalcemic primary hyperparathyroidism is not associated with cardiometabolic alterations

PURPOSE

Cardiometabolic disorders are non-classical complications of hypercalcemic primary hyperparathyroidism (HC-PHPT), but whether this risk connotes normocalcemic PHPT (NC-PHPT) remains to be elucidated. We investigated cardiometabolic alterations in both forms of PHPT, looking for their association with indices of disease activity.

METHODS

Patients with HC-PHPT (n = 17), NC-PHPT (n = 17), and controls (n = 34) matched for age, sex, and BMI were assessed for glucose, lipid, blood pressure alterations, and history of cardiovascular events to perform a case-control study at an ambulatory referral center for Bone Metabolism Diseases.

RESULTS

NC-PHPT, in comparison to controls, showed similar glucose (mean ± SD, 88 ± 11 vs 95 ± 22 mg/dl), total cholesterol (199 ± 25 vs 207 ± 36 mg/dl), and systolic blood pressure levels (SBP, 132 ± 23 vs 132 ± 19 mmHg), together with a comparable frequency of glucose alterations (6% vs 9%), lipid disorders (41% vs 50%) and hypertension (53% vs 59%, p = NS for all comparisons). Conversely, all these abnormalities were more prevalent in HC-PHPT vs controls (p < 0.05). When compared to NC-PHPT, HC-PHPT showed higher glucose (113 ± 31 mg/dl), total cholesterol (238 ± 43 mg/dl), and SBP levels (147 ± 15 mmHg) as well as an increased frequency of glucose (41%) and lipid alterations (77%) and a higher number of cardiovascular events (18% vs 0%, p < 0.05 for all comparisons). Among indices of PHPT activity, calcium levels displayed a significant correlation with glucose (R = 0.46) and SBP values (R = 0.60, p < 0.05).

CONCLUSION

NC-PHPT is not associated with cardiovascular alterations. The predominant pathogenetic role of hypercalcemia in the development of cardiometabolic disorders could account for the absence of such alterations in NC-PHPT.

Unusual body weight loss due to primary hyperparathyroidism: A case study with literature review

Brown tumors (osteitis fibrosa cystica) are rare pathognomonic signs that occur in patients with primary hyperparathyroidism (PHPT). Brown tumors can exist in multiple bones and can easily be misdiagnosed as a metastatic tumor or multiple myeloma. It is also localized in the forearm, humerus, and leg. The symptoms of hypercalcemia, pathologic fracture, and bodyweight loss may increase the diagnostic difficulty of brown tumors because multiple myeloma and bone metastasis also show the same symptoms. We studied a 68-year-old woman who had experienced unusual bodyweight loss in the past 6 months (56kg-40kg) and bone pain. She went to the hospital after a fall with a complaint of bone pain. An X-ray revealed a left bubbly-like cystic change and multiple fractures at the left ulna midshaft. Upon investigation, the level of intact parathyroid hormone was ascertained to be 1800 (normal: 10-60) pg/ml. Microscopically, the tumor demonstrated a benign bone lesion and was compatible with osteitis fibrosa cystica due to PHPT. The parathyroid scan (Tc-99 m sestamibi) indicated right parathyroid hyperplasia, which was later confirmed by a parathyroidectomy. She was diagnosed with osteitis fibrosa cystica associated with PHPT due to a parathyroid adenoma. PHPT can be presented with multiple fractures, bone pain, and bodyweight loss. Therefore, if a patient presents these symptoms, PHPT should be considered.

The Eucalcemic Patient With Elevated Parathyroid Hormone Levels

Primary hyperparathyroidism (PHPT) is classically characterized by hypercalcemia with elevated or inappropriately normal parathyroid hormone (PTH) levels. Elevated PTH levels in the presence of normal calcium levels are not infrequently found during the evaluation of metabolic bone disorders or kidney stone disease. This can be caused by secondary hyperparathyroidism (SHPT) or normocalcemic primary hyperparathyroidism (NPHPT). NPHPT is due to autonomous parathyroid function whereas SHPT is caused by a physiologic stimulation to PTH secretion. Many medical conditions and medications can contribute to SHPT, and differentiation between SHPT and NPHPT may be difficult. Cases are presented to illustrate examples. In this paper, we review the distinction between SHPT and NPHPT as well as end organ effects of NPHPT and outcomes of surgery in NPHPT. We suggest that the diagnosis of NPHPT be made only after careful exclusion of causes of SHPT and consideration of medications that can increase PTH secretion. Further, we advise a conservative approach to surgery in NPHPT.

The impact of vitamin D deficiency on clinical, biochemical and metabolic parameters in primary hyperparathyroidism

BACKGROUND

It has been suggested that vitamin D deficiency is associated with worse clinical outcomes in primary hyperparathyroidism (PHPT). We aimed to evaluate the relationship between vitamin D deficiency and clinical, biochemical and metabolic parameters in PHPT patients.

METHODS

A total of 128 patients with biochemically confirmed PHPT were included. Patients were categorized as vitamin D deficient if 25-OH vitamin D was <50nmol/L, or normal if vitamin D was ≥50nmol/L. Biochemical parameters, bone mineral densitometry (BMD), and urinary tract and neck ultrasonography were assessed.

RESULTS

In the study group, 66 (51.6%) patients had vitamin D deficiency and 60 (48.4%) had normal vitamin D levels. Nephrolithiasis and osteoporosis were found in 26.6% and 30.5% of subjects, respectively. The prevalence of metabolic syndrome (MetS), obesity (BMI≥30kg/m²) and hypertension (HTN) were higher in the vitamin D deficient group when compared to the normal group (p=0.04, p=0.01 and p=0.03, respectively). There was no difference regarding the presence of nephrolithiasis and osteoporosis between the groups. The mean adenoma size was similar in both groups.

CONCLUSIONS

Vitamin D deficiency was not associated with osteoporosis, nephrolithiasis, adenoma size or biochemical parameters in PHPT. However, vitamin D deficiency may be a risk factor for developing HTN and MetS in PHPT.

The influence of parathyroidectomy on cardiometabolic risk factors in patients with primary hyperparathyroidism: a systematic review and meta-analysis

PURPOSE

Primary hyperparathyroidism (PHPT) is associated with increased risk of cardiovascular morbidity and mortality. We aim to determine whether parathyroidectomy (PTX) can change cardiometabolic risk factors including serum lipids, glycemic parameters, systolic and diastolic blood pressure, C reactive protein (CRP), and body mass index (BMI).

METHODS

MEDLINE, Web of Science, Scopus, and Google Scholar were searched for relevant articles published till June 2020. Fixed-effect or random-effects models were used to estimate the weighted mean difference (WMD) and 95% CI for outcomes where applicable.

RESULTS

In total, 34 studies were eligible to be included in the current meta-analysis. Our results indicated no favorable change in serum triglyceride (n = 13, WMD = -0.06, 95% CI: -0.15, 0.03 mmol/L), total cholesterol (n = 15, WMD = 0.01, 95% CI: -0.14, 0.16 mmol/L), LDL-C (n = 10, WMD = -0.01, 95% CI: -0.17, 0.19 mmol/L), HDL-C (n = 10, WMD = 0.03, 95% CI: -0.001, 0.06 mmol/L), and CRP (n = 5, WMD = 0.82, 95% CI: -0.01, 1.64 mg/L) after PTX in PHPT patients. However, glucose (n = 24, WMD = -0.16, 95% CI: -0.26, -0.06 mmol/L), serum insulin (n = 12, WMD = -1.11, 95% CI: -1.73, -0.49 µIU/mL), systolic (n = 17, WMD = -10.14, 95% CI: -12.27, -8.01 mmHg), and diastolic (n = 16, WMD = -5.21, 95% CI: -7.0, -3.43 mmHg) blood pressures were decreased after PTX, whilst a significant increase was observed in BMI (n = 13, WMD = 0.35, 95% CI: 0.19, 0.51 kg/m²).

CONCLUSIONS

PTX could improve glycemic parameters and blood pressure, without any significant change in serum lipoproteins and CRP.

Normocalcemic primary hyperparathyroidism: an update

Normocalcemic primary hyperparathyroidism (NPHPT) is diagnosed in the setting of elevated PTH concentrations with consistently normal albumin-adjusted and ionized serum calcium levels, in absence of secondary causes for elevated PTH concentrations. In order to confirm persistence of the hyperparathyroid state, PTH levels should be elevated on at least two occasions over a 3 to 6 months period. The prevalence of NPHPT depends on the population studied. Data from different studies are often not comparable; indeed, different criteria have been used to exclude secondary hyperparathyroidism. Notwithstanding such limits, the prevalence of NPHPT in studies including ionized calcium dosage was between 0.5% and 0.7%. Available data suggest that patients with NPHPT are likely to have more skeletal, kidney and metabolic complications compared to healthy subjects, but almost all studies suffer from possible misclassification of patients due to lack of ionized calcium dosage. The management of NPHPT is controversial in part due to lack of solid data about the natural history. However, surgical treatment is currently performed more frequently than in the past, although studies do not show, so far, a clear benefit from intervention.

Parathyroidectomy improves cardiovascular risk factors in normocalcemic and hypercalcemic primary hyperparathyroidism

BACKGROUND

Parathyroidectomy has ameliorated cardiovascular risk factors in patients with hypercalcemic primary hyperparathyroidism (PHPT), but the effect of parathyroidectomy on normocalcemic PHPT is not exactly known. This case-controlled study aimed to investigate the effect of parathyroidectomy on cardiovascular risk factors in patients with normocalcemic and hypercalcemic PHPT.

METHODS

Subjects with normocalcemic PHPT (n = 35), age- and sex-matched hypercalcemic PHPT (n = 60) and age- and sex-matched control (n = 60) were included. Cardiometabolic disorders were investigated with traditional cardiometabolic risk factors and the Framingham cardiovascular risk score (CRS) before and 6 months after parathyroidectomy.

RESULTS

Diabetes, dyslipidemia, hypertension, obesity, insulin resistance, osteoporosis, having fractures were similarly increased in the hypercalcemic and normocalcemic PHPT groups (p > 0.05) compared with the controls (p < 0.05). Blood pressures, glucose metabolism (glucose, insulin, HOMA-IR) and lipid profiles were similarly increased in the PHPT groups (p > 0.05) compared with the controls (p < 0.05). After parathyroidectomy, blood pressures, serum total cholesterol, and HOMA-IR were decreased in both PHPT groups (p < 0.05). CRS was lower in the controls (5.74 ± 3.24, p < 0.05). After parathyroidectomy, CRS was decreased in the normocalcemic (11.98 ± 10.11 vs. 7.37 ± 4.48) and hypercalcemic (14.62 ± 11.06 vs. 8.05 ± 7.72) PHPT groups. Increased blood pressures were independent predictors of serum iPTH.

CONCLUSION

The normocalcemic and hypercalcemic PHPT groups had similarly increased cardiovascular risk factors, even independently of serum calcium. Parathyroidectomy ameliorated the increased cardiovascular risk factors in both normocalcemic and hypercalcemic PHPT.

Cardiovascular risk and metabolic syndrome in primary hyperparathyroidism and their correlation to different clinical forms

Cardiometabolic disorders have been associated with primary hyperparathyroidism (PHPT), while the relationship of cardiovascular risk score (CRS) and metabolic syndrome (MS) with different clinical presentation of PHPT remains undefined. Our aim was to evaluate CRS, MS and its components in PHPT looking for their correlation to different clinical forms. In 68 consecutive PHPT patients and 68 matched controls, CRS, MS and its components were assessed to perform an observational case-control study at an ambulatory referral center for Bone Metabolism Diseases. Patients were stratified in symptomatic and asymptomatic PHPT; these latter were divided in high-risk and low-risk subgroups for end-organ damage. An increased proportion of PHPT patients had intermediate-high CRS and MS (mean, 95 % Confidence Interval (CI) 51.5 %, 39.6-63.3 and 20.6 %, 11.0-30.2, respectively, p < 0.02 vs. controls). Intermediate-high CRS was prevalent both in symptomatic and low-risk asymptomatic PHPT while MS resulted prevalent in low-risk asymptomatic but not in symptomatic PHPT. Type 2 DM, IFG, mixed dyslipidemia, hypertriglyceridemia, HDL-hypocholesterolemia, and LDL-hypercholesterolemia predominated in low-risk asymptomatic, while only LDL-hypercholesterolemia prevailed also in symptomatic PHPT. In patients and controls without cardiometabolic risk factors, HOMA-IR index was significantly increased in PHPT vs. controls (p < 0.03) and associated to total calcium (R = 0.73; p < 0.001). By multivariate analysis low-risk asymptomatic PHPT predicted MS after adjusting for age, sex, and BMI. Our data show an increased frequency of intermediate-high CRS both in symptomatic and low-risk asymptomatic PHPT while MS prevails in low-risk asymptomatic PHPT, supporting the potential for cardiovascular morbidity and mortality also in this form.