Ultrafast intraoperative parathyroid hormone monitoring system: prospective, multicentre, clinical validity study.

BACKGROUND: Intraoperative parathyroid hormone (PTH) monitoring is a proven and reliable adjunct to parathyroid surgery, able to improve the outcomes and efficiency of the diagnostic and therapeutic pathway for patients with primary hyperparathyroidism. This study evaluated the innovative, compact, fully automated NBCL CONNECT Analyzer, which can measure whole-blood PTH in 5 min. METHODS: A prospective multicentre study was conducted in stages: results reviews, recommendations, and implementation of improvements to the mechanical design, components of cartridges, calibration, and sampling protocols. Patients undergoing parathyroidectomy had PTH levels measured on the Analyzer and main laboratory platforms, either Roche or Abbott. The Miami criterion of a 50% drop in PTH concentration was used to define biochemical cure during surgery, and normal postoperative calcium level as cure of primary hyperparathyroidism. Measurements on the Analyzer were done by laboratory staff in London and nurses in Stuttgart. The Pearson coefficient (R) and Wilcoxon test were used for statistical analysis. RESULTS: Some 234 patients (55 male, 179 female) with a median age of 58.5 (age full range 15-88) years underwent parathyroidectomy (195 minimally invasive, 38 bilateral neck exploration, 1 thoracoscopic; 12 conversions) for primary hyperparathyroidism between November 2021 and July 2022. Primary hyperparathyroidism was cured in 225 patients (96.2%). The sensitivity, specificity, and overall accuracy of the Analyzer assay in predicting biochemical cure were 83.9, 100, and 84.8% in phase 1; 91.2, 100, and 91.3% in phase 2; and 98.6, 100, and 98.6% in phase 3. There were no false-positive results (positive predictive value 100%). Correlations between Analyzer measurements and those obtained using the Roche device were very strong (R = 0.98, P < 0.001 in phase 1; R = 0.92, P < 0.001 in phase 2; R = 0.94, P < 0.001 in phase 3), and correlations for Analyzer readings versus those from the Abbott platform were strong (R = 0.82, P < 0.001; R = 0.89, P < 0.001; R = 0.91, P < 0.001). The Analyzer showed continued good mechanical performance, with stable and repeatable operations (calibrations, quality controls). Introducing a stricter sampling protocol and improvements in the clot-detecting system led to a decrease in the number of clotted samples and false-negative results. Outcomes were not affected by measurements performed either by nurses or laboratory staff. CONCLUSION: Intraoperative PTH monitoring during parathyroid surgery can be done accurately, simply, and quickly in whole blood using the Analyzer.

Emerging pattern of asymptomatic hyperparathyroidism in South India - a six-year retrospective study.

INTRODUCTION: Primary hyperparathyroidism (PHPT) is a common endocrine disease with a variable presentation. There is a recent increase in the number of asymptomatic cases due to the use of multichannel automated analyzers.

Parathyroid fine needle aspiration with PTH washout: Can it lead to parathyroid cell seeding in primary hyperparathyroidism?

Although parathyroid fine-needle aspiration (P-FNA) with parathyroid hormone (PTH) washout is effective in detecting preoperative parathyroid lesions, it also presents risks such as fibrosis, hematoma, and, in rare cases, tumor seeding. This study aimed to investigate whether P-FNA with PTH washout leads to the seeding of parathyroid cells along the path of the needle. A retrospective analysis was conducted on patients undergoing minimally invasive parathyroidectomy guided by preoperative PTH washout. Permanent pathology reports, imaging data, and postoperative serum parathyroid hormone and calcium levels were assessed to determine the effectiveness and safety of the procedure. Complications following P-FNA with PTH washout were also reviewed using data from the patient registration system of Bulent Ecevit University. The procedure accurately localized parathyroid adenomas in 87 patients who underwent ultrasound-guided parathyroidectomy following preoperative P-FNA and PTH washout. Postoperatively, 75 patients showed normal parathyroid hormone and calcium levels. Two patients required secondary surgery for contralateral adenomas. Critically, there was no evidence of P-FNA with PTH washout-induced parathyromatosis or seeding during the follow-up. Effective adenoma localization is crucial for successful minimally invasive surgery of hyperparathyroidism. Our study indicates that combining preoperative P-FNAB with PTH washout and imaging enhances adenoma detection, especially when intraoperative PTH measurements are not available, thus improving surgical outcomes. Notably, we found no evidence of cell implantation after P-FNA, suggesting the safety and efficacy of this method for preventing parathyroid cell seeding.

Characteristics, management and outcomes of primary hyperparathyroidism from 2009 to 2021: a single centre report from South Africa.

BACKGROUND: There has been a notable shift towards the diagnosis of less severe and asymptomatic primary hyperparathyroidism (PHPT) in developed countries. However, there is a paucity of recent data from sub-Saharan Africa (SSA), and also, no reported data from SSA on the utility of intra-operative parathyroid hormone (IO-PTH) monitoring. In an earlier study from Inkosi Albert Luthuli Central Hospital (IALCH), Durban, South Africa (2003-2009), majority of patients (92.9%) had symptomatic disease. The aim of this study was to evaluate the clinical profile and management outcomes of patients presenting with PHPT at IALCH. METHODS: A retrospective chart review of patients with PHPT attending the Endocrinology clinic at IALCH between July 2009 and December 2021. Clinical presentation, laboratory results, radiologic findings, surgical notes and histology were recorded. RESULTS: Analysis included 110 patients (87% female) with PHPT. Median age at presentation was 57 (44; 67.5) years. Symptomatic disease was present in 62.7% (n:69); 20.9% (n:23) had a history of nephrolithiasis and 7.3% (n:8) presented with previous fragility fractures. Mean serum calcium was 2.87 ± 0.34 mmol/l; median serum-PTH was 23.3 (15.59; 45.38) pmol/l, alkaline phosphatase 117.5 (89; 145.5) U/l and 25-hydroxyvitamin-D 42.9 (33.26; 62.92) nmol/l. Sestamibi scan (n:106 patients) identified an adenoma in 83.02%. Parathyroidectomy was performed on 84 patients with a cure rate of 95.2%. Reasons for conservative management (n:26) included: no current surgical indication (n:7), refusal (n:5) or deferral of surgery (n:5), loss to follow-up (n:5) and assessed as high anaesthetic risk (n:4). IO-PTH measurements performed on 28 patients indicated surgical success in 100%, based on Miami criteria. Histology confirmed adenoma in 88.1%, hyperplasia in 7.1% and carcinoma in 4.8%. Post-operative hypocalcaemia developed in 30 patients (35.7%), of whom, 14 developed hungry bone syndrome (HBS). In multivariate analysis, significant risk factors associated with HBS included male sex (OR 7.01; 95% CI 1.28, 38.39; p 0.025) and elevated pre-operative PTH (OR 1.01; 95% CI 1.00, 1.02; p 0.008). CONCLUSIONS: The proportion of asymptomatic PHPT has increased at this centre over the past decade but symptomatic disease remains the dominant presentation. Parathyroidectomy is curative in the majority of patients. IO-PTH monitoring is valuable in ensuring successful surgery.

Primary hyperparathyroidism in pregnancy: a case report highlighting uncommon complication.

Primary hyperparathyroidism (PHPT) is characterized by elevated levels of calcium and parathyroid hormone (PTH). However, the interpretation of diagnostic tests, such as serum calcium and PTH levels, is complex in pregnant women. The aim of this report is to present a case of PHTP in a pregnant adolescent, with a special emphasis on an uncommon complication, as well as diagnostic and treatment strategies. A 17-year-old pregnant female presented with hyperemesis gravidarum and neurological symptoms, leading to the diagnosis of cerebral venous thrombosis. Further investigations revealed hypercalcemia and persistently elevated PTH levels, consistent with PHPT. After localization studies, the patient underwent an emergency parathyroidectomy with a diagnosis of parathyroid adenoma. During follow-up, intrauterine growth restriction and severe preeclampsia developed, necessitating an emergency cesarean section. Both the mother and neonate had favorable outcomes. PHPT is an infrequent condition in the pregnant population, and its diagnosis can be challenging due to the overlap of symptoms with normal physiological changes during pregnancy. The occurrence of uncommon complications, such as thrombotic phenomena, highlights the need for a comprehensive approach to ensure early detection and management. In most cases, parathyroidectomy is the treatment of choice.

El hiperparatiroidismo primario (HPTP) se caracteriza por niveles elevados de calcio y hormona paratiroidea (PTH). Sin embargo, la interpretación de pruebas diagnósticas, como los niveles de calcio sérico y PTH, es compleja en mujeres embarazadas. El objetivo de este reporte es presentar un caso de HPTP en una adolescente embarazada, con especial hincapié en una complicación infrecuente, así como en las estrategias diagnósticas y de tratamiento. Una mujer embarazada de 17 años presentó hiperémesis gravídica y síntomas neurológicos, lo que llevó al diagnóstico de trombosis venosa cerebral. Posteriores investigaciones revelaron hipercalcemia y niveles persistentemente elevados de PTH, consistentes con HPTP. Tras la realización de estudios de localización, la paciente fue sometida a una paratiroidectomía de emergencia con diagnóstico de adenoma de paratiroides. Durante el seguimiento, se desarrolló restricción del crecimiento intrauterino y preeclampsia grave, lo que resultó en la necesidad de realizar una cesárea de emergencia. Tanto la madre como el neonato evolucionaron favorablemente. El HPTP es una condición infrecuente en la población embarazada y su diagnóstico puede ser desafiante por la superposición de síntomas con los cambios fisiológicos normales del embarazo. La aparición de complicaciones infrecuentes, como fenómenos trombóticos, resalta la necesidad de un abordaje integral para garantizar la detección y el manejo temprano. En la mayoría de los casos, la paratiroidectomía es el tratamiento de elección.

Preoperative Lateralization and Diagnostic Value of Selective Bilateral Internal Jugular Venous Sampling in Primary Hyperparathyroidism: Single-Center Experience.

Background and Objectives: Primary hyperparathyroidism (pHPT) is a common endocrine disorder caused by excessive production of parathyroid hormone (PTH) leading to elevated calcium levels. Diagnosis is primarily based on biochemical evaluation, and surgery is the curative treatment. Imaging techniques like ultrasound and Tc-99m Sestamibi scintigraphy are used for localization, but selective Internal Jugular Venous (SVS) becomes valuable in cases of inconclusive or conflicting results. This study evaluated the diagnostic efficacy of SVS for localizing parathyroid adenomas in cases where non-invasive radiological diagnostic methods yielded inconclusive results or negative findings despite clinical symptoms suggestive of pHPT. Materials and Methods: In this retrospective study, a total of 28 patients diagnosed with pHPT underwent SVS at a tertiary center known for receiving referrals from 2017 to 2022. The diagnoses were confirmed through biochemical analysis. The SVS results in 22 patients were compared with non-invasive imaging methods, including ultrasound, scintigraphy, and computed tomography with/without contrast material. SVS was indicated when at least two non-invasive diagnostic procedures failed to clearly localize the parathyroid glands or provided ambiguous results. Results: SVS demonstrated higher sensitivity for localizing parathyroid adenomas compared to non-invasive imaging methods, accurately lateralizing the adenoma in 68.18% of cases. Among the SVS findings, 31.8% of patients had negative results, with 9.1% not having clinically proven parathyroid adenoma, while 22.7% had false negative SVS findings but were later confirmed to have adenoma during surgery. Ultrasound correctly identified the location in 45.45% of cases, CT in 27.27%, and scintigraphy in 40.9%. Conclusions: SVS is a valuable diagnostic tool for accurately localizing parathyroid adenomas in patients with inconclusive non-invasive imaging results. It aids in targeted surgical interventions, contributing to improved management and treatment outcomes in primary hyperparathyroidism.

Neonatal hypocalcaemic seizures unmasking asymptomatic maternal primary hyperparathyroidism.

Hypocalcaemia is a common cause of neonatal seizures. Here, we present a breastfed neonate with smooth perinatal transition and no family history of seizures presenting at 3 weeks with recurrent multifocal clonic seizures. On evaluation, the neonate was found to have low iCa and total calcium. 25-hydroxy vitamin D (25(OH)D) level was low and intact parathyroid hormone (iPTH) was inappropriately normal. The maternal evaluation revealed high calcium and low phosphate levels. iPTH was very high and 25(OH)D was very low in the mother. Sestamibi scan showed a left inferior parathyroid adenoma in the mother. Maternal primary hyperparathyroidism causing hypercalcaemia can suppress parathyroid activity in the fetus, resulting in inappropriate parathyroid response to hypocalcaemia after birth causing recurrent hypocalcaemic seizures. So neonatal hypocalcaemic seizures need careful evaluation of the neonate and the mother at times and can help both mother and neonate.

Testing for Primary Hyperparathyroidism in 17,491 Patients With Hypercalcemia.

BACKGROUND: Primary hyperparathyroidism (PHPT) is underdiagnosed and associated with many adverse health effects. Historically, many hypercalcemic patients have not received parathyroid hormone (PTH) testing; however, underlying reasons are uncertain. Our goals are to determine the PTH testing rate among hypercalcemic individuals at a large academic health system and to assess for characteristics associated with testing versus not testing for PHPT to inform future strategies for closing testing gaps. METHODS: This retrospective study included adult patients with ≥1 elevated serum calcium result between 2018 and 2022. Based on the presence or absence of a serum PTH result, individuals were classified as "screened" versus "unscreened" for PHPT. Demographic and clinical characteristics of these groups were compared. RESULTS: The sample comprised 17,491 patients: 6567 male (37.5%), 10,924 female (62.5%), mean age 59 y. PTH testing was performed in 6096 (34.9%). Characteristics independently associated with the greatest odds of screening were 5+ elevated calcium results (odds ratio [OR] 5.02, P < 0.0001), chronic kidney disease (OR 3.63, P < 0.0001), maximum calcium >12.0 mg/dL (OR 2.48, P < 0.0001), and osteoporosis (OR 2.42, P < 0.0001). Characteristics associated with lowest odds of screening were age <35 y (OR 0.60, P < 0.0001), death during the study period (OR 0.68, P < 0.0001), age ≥85 y (OR 0.70, P = 0.0007), and depression (OR 0.84; P = 0.0081). CONCLUSIONS: Only 35% of hypercalcemic patients received PTH testing. Although the presence of PHPT-associated morbidity was generally associated with increased rates of screening, hypercalcemic patients with depression were 16% less likely to be tested.

Modern Trends for Primary Hyperparathyroidism: Intervening on Less Biochemically Severe Disease.

INTRODUCTION: Primary hyperparathyroidism (PHPT) is defined by autonomous parathyroid hormone secretion, which has broad physiologic effects. Parathyroidectomy is the only cure and is recommended for patients demonstrating symptomatic disease and/or end organ damage. However, there may be a benefit to intervening before the development of complications. We sought to characterize institutional trends in the biochemical and symptomatic presentation of PHPT and the associated cure and complication rates. METHODS: We performed a retrospective cohort study of 1087 patients undergoing parathyroidectomy for PHPT, evaluating patients at 2-year intervals between 2002 and 2019. We identified signs and symptoms of PHPT based on the 2016 American Association of Endocrine Surgery Guidelines. Trends were evaluated with Kruskal Wallis, Chi-square tests, and Fisher's exact tests. RESULTS: Patients with PHPT are presenting with lower parathyroid hormone (P = 0.0001) and calcium (P = 0.001) in the current era. Parathyroidectomy is more commonly performed for borderline guideline concordant patients with osteopenia (40.2%) and modest calciuria (median 246 mg/dL/24 h). 93.7% are cured, with no difference over time or between groups by guideline concordance. CONCLUSIONS: Parathyroidectomy is increasingly performed for patients who demonstrate modest bone and renal dysfunction. Patients experience excellent cure rates and rarely experience postoperative hypocalcemia, suggesting a role for broader surgical indications.

Clinical and outcome comparison of genetically positive vs. negative patients in a large cohort of suspected familial hypocalciuric hypercalcemia.

OBJECTIVE: Biochemical suspicion of familial hypocalciuric hypercalcemia (FHH) might provide with a negative (FHH-negative) or positive (FHH-positive) genetic result. Understanding the differences between both groups may refine the identification of those with a positive genetic evaluation, aid management decisions and prospective surveillance. We aimed to compare FHH-positive and FHH-negative patients, and to identify predictive variables for FHH-positive cases. DESIGN: Retrospective, national multi-centre study of patients with suspected FHH and genetic testing of the CASR, AP2S1 and GNA11 genes. METHODS: Clinical, biochemical, radiological and treatment data were collected. We established a prediction model for the identification of FHH-positive cases by logistic regression analysis and area under the ROC curve (AUROC) was estimated. RESULTS: We included 66 index cases, of which 30 (45.5%) had a pathogenic variant. FHH-positive cases were younger (p = 0.029), reported more frequently a positive family history (p < 0.001), presented higher magnesium (p < 0.001) and lower parathormone levels (p < 0.001) and were less often treated for hypercalcemia (p = 0.017) in comparison to FHH-negative cases. Magnesium levels showed the highest AUROC (0.825, 95%CI: 0.709-0.941). The multivariate analysis revealed that family history and magnesium levels were independent predictors of a positive genetic result. The predictive model showed an AUROC of 0.909 (95%CI: 0.826-0.991). CONCLUSIONS: The combination of magnesium and a positive family history offered a good diagnostic accuracy to predict a positive genetic result. Therefore, the inclusion of magnesium measurement in the routine evaluation of patients with suspected FHH might provide insight into the identification of a positive genetic result of any of the CaSR-related genes.

The Ca∗Cl/P Ratio: A Novel and More Appropriate Screening Tool for Normocalcaemic or Overt Primary Hyperparathyroidism.

OBJECTIVE: The main purpose of this study was to explore the diagnostic performance of the Ca∗Cl/P ratio for primary hyperparathyroidism (PHPT), especially normocalcaemic PHPT (NPHPT), to assist health care providers in making reliable and rapid clinical identifications. METHODS: From January 1, 2013, to March 31, 2023, 230 PHPT patients, including 65 with NPHPT and 230 sex- and age-matched controls, were enrolled in this retrospective study. Differences between hypercalcaemic PHPT (HPHPT) and NPHPT and between them and their respective controls were analyzed. The diagnostic accuracy of the Ca∗Cl/P ratio, Ca/P ratio, Cl/P ratio and albumin-corrected calcium was assessed by the area under the receiver operating characteristic curve. RESULTS: Compared with corresponding controls, NPHPT and HPHPT patients both had significantly higher Ca ∗ Cl/P ratios (271.64 ± 51.74 vs 192.71 ± 26; 419.91 ± 139.11 vs 199.14 ± 36.75, P < .001). In the overall cohort, the ROC-AUC of the Ca∗Cl/P ratio (0.964, 95% CI = 0.943-0.979) for diagnosis of PHPT patients was superior to albumin-corrected calcium (0.959, 95% CI = 0.934-0.973), the Ca/P ratio (0.956, 95% CI = 0.934-0.973), and the Cl/P ratio (0.923, 95% CI = 0.895-0.946). A Ca ∗ Cl/P ratio above 239.17 mmol/L, with sensitivity (0.952), specificity (0.922), PPV (0.924), NPV (0.951) and accuracy (0.937), can distinguish PHPT patients from healthy individuals. Furthermore, the Ca ∗ Cl/P ratio yielded a sensitivity of 0.831, specificity of 0.938, PPV of 0.931, NPV of 0.847 and accuracy of 0.885 for NPHPT. CONCLUSION: The Ca∗Cl/P ratio provides excellent diagnostic power for diagnosis of PHPT, especially NPHPT.

Patient perspectives on barriers to obtaining surgery for primary hyperparathyroidism: A qualitative review.

BACKGROUND: The purpose of this study was to qualitatively explore patient-reported barriers to surgery for primary hyperparathyroidism (PHPT) and identify actionable interventions to improve access to surgical care. METHODS: We recruited forty-nine patients in an endocrine surgery clinic at a large, academic medical to participate in an 11- question phone interview. All interviewees underwent parathyroidectomy for primary hyperparathyroidism. Responses were recorded and a codebook of qualitative themes, blinded to patient race and sex, was created by 3 independent reviewers. Comments were subsequently sorted into the codebook with patient demographic information. RESULTS: Patients that experienced delays in parathyroidectomy most commonly cited "issues with the referral process" and "missed diagnosis" as the cause. Patients were asked to identify the most challenging part about the surgery process. Commonly evoked themes among patients of both races and sexes included "transportation" and "financial" with subthemes of "no ride," "distance from surgeon," "insurance," and "difficulty taking time off work." Patients were asked to name actionable interventions to improve access to surgical care. The most commonly evoked theme involved "support systems," with subthemes of "transportation assistance," "financial," and "patient advocacy." Physician factors were also commonly evoked among patients of both races with subthemes of "knowledge", "communication," and "listening." CONCLUSION: PHPT patients cited multiple barriers to undergoing surgery. Future work can focus on examining these questions with a larger patient cohort and examining delays at the referral and diagnosis stage, which was most commonly cited by our respondents.

Genetics of hereditary forms of primary hyperparathyroidism.

Primary hyperparathyroidism (PHPT), a relatively common disorder characterized by hypercalcemia with raised or inappropriately normal serum parathyroid hormone (PTH) concentrations, may occur as part of a hereditary syndromic disorder or as a non-syndromic disease. The associated syndromic disorders include multiple endocrine neoplasia types 1-5 (MEN1-5) and hyperparathyroidism with jaw tumor (HPT-JT) syndromes, and the non-syndromic forms include familial hypocalciuric hypercalcemia types 1-3 (FHH1-3), familial isolated hyperparathyroidism (FIHP), and neonatal severe hyperparathyroidism (NS-HPT). Such hereditary forms may occur in > 10% of patients with PHPT, and their recognition is important for implementation of gene-specific screening protocols and investigations for other associated tumors. Syndromic PHPT tends to be multifocal and multiglandular with most patients requiring parathyroidectomy with the aim of limiting end-organ damage associated with hypercalcemia, particularly osteoporosis, nephrolithiasis, and renal failure. Some patients with non-syndromic PHPT may have mutations of the MEN1 gene or the calcium-sensing receptor (CASR), whose loss of function mutations usually cause FHH1, a disorder associated with mild hypercalcemia and may follow a benign clinical course. Measurement of the urinary calcium-to-creatinine ratio clearance (UCCR) may help to distinguish patients with FHH from those with PHPT, as the majority of FHH patients have low urinary calcium excretion (UCCR < 0.01). Once genetic testing confirms a hereditary cause of PHPT, further genetic testing can be offered to the patients' relatives and subsequent screening can be carried out in these affected family members, which prevents inappropriate testing in normal individuals.

How often are intrathyroidal parathyroid glands a cause of primary hyperparathyroidism, and how should they be managed?

BACKGROUND: The purpose of our study was to determine the frequency and management of intrathyroidal parathyroid glands in patients with primary hyperparathyroidism and evaluate whether intrathyroidal parathyroid glands were more often superior or inferior glands. METHODS: A retrospective review of the prospective parathyroid database was completed to determine the number of patients with primary hyperparathyroidism and an intrathyroidal parathyroid gland. Demographic data, laboratory and localization studies, operative management, pathology, and outcome were determined for patients with an intrathyroidal parathyroid gland and were compared with patients with an extrathyroidal parathyroid gland. RESULTS: From 1990-2023, 808 patients were operated on for primary hyperparathyroidism; 17 (2%) patients had an intrathyroidal parathyroid gland, an adenoma in 15 (88.2%), and a hyperplastic gland in 2 (11.8%). The mean age was 53 years; 16 (94%) patients were female. Mean calcium and parathyroid hormone was 12 mg/dL and 150 pg/mL, and there were no differences from the extrathyroidal parathyroid group. Ultrasound and Sestamibi imaging were valuable in identifying an intrathyroidal parathyroid gland in 10 of 13 patients and 13 of 17 patients, respectively. Local excision was performed in 9 (53%) patients and lobectomy in 8 (47%) patients. Intraoperative parathyroid hormone was measured and predictive of cure in 12 patients. The location of intrathyroidal parathyroid glands was determined in 15 patients and was inferior in 11 (73%). All patients were cured. No patient developed recurrent disease after a median 54-month follow-up. CONCLUSION: Intrathyroidal parathyroid glands are the cause of primary hyperparathyroidism in 2% of patients and are most often inferior glands. Local excision was accomplished in 53% of our patients.

Association of patient-practitioner sex concordance with specialist referral in primary hyperparathyroidism.

BACKGROUND: Prior research has demonstrated barriers to the workup and management of primary hyperparathyroidism. As recent data have suggested that patient and practitioner sex concordance is associated with lower surgical complications, we sought to evaluate the effect of sex concordance on referral for primary hyperparathyroidism. METHODS: We queried an institutional database for patients with first-incident hypercalcemia and subsequent biochemical evidence of primary hyperparathyroidism between 2010 and 2018. Primary care practitioner and endocrinologist sex, laboratory values, and complications of primary hyperparathyroidism were collected. Sex concordance (male patient/male practitioner or female patient/female practitioner) was evaluated as a binary predictor of specialist evaluation using logistic regression and Cox proportional hazards modeling. RESULTS: Among 1,100 patients, mean age was 62.5 (standard deviation 13.6), and 74% were female sex. Primary care practitioner sex was 52% female, and 63% of patients had sex concordance with their primary care practitioner. Endocrinologist sex was 59% female, and 45% of patients had sex concordance with their endocrinologist. Patients with sex concordance with their primary care practitioner (70 vs 80%, P = .001) and endocrinologist (71 vs 82%, P < .001) were less likely to be female sex compared to those with discordance. After adjusting for demographics and clinical covariates, those patients with primary care practitioner sex concordance had 32% higher odds of endocrinologist evaluation (odds ratio 1.32, 95% confidence interval 1.003-1.734, P = .047). Similarly, those patients with endocrinologist sex concordance had a 48% higher rate of surgeon evaluation (hazard ratio 1.48, confidence interval 1.1-2.0, P = .009). Stratified analysis revealed that sex discordance reduced the rate of surgeon referral for female patients (hazard ratio 0.63, confidence interval 0.44-0.89, P = .008) but not male patients (hazard ratio 1.06, CI 0.58-1.93, P = .861). CONCLUSION: Sex discordance between patients and their health care professionals may contribute to under-referral in primary hyperparathyroidism. Further evaluation of the effect of patient and practitioner identities on communication and decision-making in surgery are needed.