Mortality and Morbidity in Mild Primary Hyperparathyroidism: Results From a 10-Year Prospective Randomized Controlled Trial of Parathyroidectomy Versus Observation

Skeletal Effect of Parathyroidectomy on Patients With Primary Hyperparathyroidism: A Systematic Review and Meta-Analysis

CONTEXT

Parathyroidectomy (PTX) is recommended for curing primary hyperparathyroidism (PHPT), although uncertainty remains regarding the extent of fracture risk reduction following surgery.

OBJECTIVE

This work aimed to compare fracture risk and bone mineral density (BMD) changes in patients with PHPT undergoing PTX vs observation (OBS).

METHODS

We systematically searched PubMed, Embase, and the Cochrane Library until September 2022, including randomized controlled trials (RCTs) and cohort studies, and reviewed citations from previous reviews. Among 1260 initial records, 48 eligible articles from 35 studies (5 RCTs; 30 cohorts) included PHPT patients receiving PTX or OBS interventions with reported fracture events at any site, including the hip, spine, or forearm, and/or BMD changes at each location. Data extraction followed Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines by 2 independent reviewers.

RESULTS

In 238 188 PHPT patients (PTX: 73 778 vs OBS: 164 410), PTX significantly reduced fractures at any site (relative risk [RR], 0.80; 95% CI, 0.74-0.86) compared to OBS. In 237 217 patients (PTX: 73 458 vs OBS: 163 759), the risk of hip fractures decreased (RR, 0.63; 95% CI, 0.52-0.76). No reduction in forearm and vertebral fractures was observed in 3574 and 3795 patients, respectively. The annual percentage BMD changes from baseline were higher in the PTX group: femoral neck, 1.91% (95% CI, 1.14-2.68); hip, 1.75% (95% CI, 0.58-2.92); radius, 1.75% (95% CI, 0.31-3.18); spine, 2.13% (95% CI, 1.16-3.10).

CONCLUSION

PTX significantly reduced overall and hip fracture risks in PHPT patients. Despite minimal BMD increase, the substantial decrease in fracture risk suggests additional benefits of PTX beyond mineral content enhancement.

No effect of surgery on kidney and cardiovascular risk factors in mild primary hyperparathyroidism: secondary analyses from a 10-year randomized controlled trial

OBJECTIVE

Renal function and the skeleton are classic target organs in primary hyperparathyroidism (PHPT), affected by the chronic course of the disease. Most patients diagnosed today exhibit mild PHPT, characterized by slight hypercalcemia and no or unspecific symptoms. Concerns have been raised that PHPT could promote deteriorating kidney function and increase cardiovascular risk directly. To examine the effect of parathyroidectomy (PTX) on mild PHPT on renal function and markers for bone turnover, cardiovascular disease (CVD), and vascular inflammation.

DESIGN

Prospective randomized controlled trial. ClinicalTrials.gov: NCT00522028.

SETTING

Eight Scandinavian referral centers.

PARTICIPANTS

From 1998 to 2005, 191 patients with mild PHPT were included in Sweden, Norway, and Denmark. Of these 150 were included in the present analyses.

INTERVENTION

Seventy patients were randomized to PTX and 80 to observation without intervention (OBS).

MEASURES

e-GFR was calculated based on creatinine and cystatin C. Markers of CVD and systemic inflammation: osteoprotegerin, vascular cell adhesion molecule 1, soluble CD40 ligand, interleukin-1 receptor antagonist, von Willebrand factor. Bone turnover markers: C-terminal telopeptide of type 1 collagen (CTX-1) and serum Procollagen type 1 N-terminal propeptide.

RESULTS

No differences in the development of renal function or vascular and systemic inflammation were detected. CTX-1 was lower in PTX after 10 years.

LIMITATIONS

Secondary analyses of a randomized controlled trial.

CONCLUSION

PTX does not appear to affect renal function or markers of CVD and vascular inflammation in mild PHPT in a ten-year perspective.

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.

Parathyroidectomy Improves Bone Density in Women With Primary Hyperparathyroidism and Preoperative Osteopenia

CONTEXT

Osteoporosis and/or bone fractures are indications of parathyroidectomy in primary hyperparathyroidism (PHPT), especially in women. However, the benefit of surgery in patients with osteopenia remains unclear.

OBJECTIVE

To evaluate bone mineral density (BMD) and bone remodeling biomarkers changes 1 year after parathyroidectomy in women with PHPT.

DESIGN

In the prospective, monocentric, observational prospective cohort with primary hyperparathyroidism patients (CoHPT) cohort, women operated for sporadic PHPT since 2016 with ≥1 year follow-up were included. BMD (dual-X ray absorptiometry) and bone remodeling biomarkers [cross-linked C-telopeptide (CTX), procollagen type 1 N-terminal propeptide (P1NP), and bone-specific alkaline phosphatases] were assessed before and 1 year after parathyroidectomy.

SETTING

Referral center.

PATIENTS

A total of 177 women with PHPT (62.5 ± 13.3 years, 83.1% menopausal, 43.9% osteopenic, and 45.1% osteoporotic) were included.

INTERVENTION

Parathyroidectomy.

MAIN OUTCOME MEASURE

BMD change between before and 1 year after parathyroidectomy.

RESULTS

Parathyroidectomy resulted in significant increase in BMD and decrease in serum bone remodeling biomarker concentrations. In the 72 patients with baseline osteopenia, mean BMD significantly increased at the lumbar spine [+0.05 g/cm2 (95% confidence interval [CI], 0.03-0.07)], the femoral neck [+0.02 g/cm2 (95% CI 0.00-0.04)], the total hip [+0.02 g/cm2 (95% CI 0.01-0.02)], and the forearm [+0.01 (95% CI 0.00-0.02)], comparable to osteoporotic patients. Among osteopenic patients, those with individual BMD gain (>0.03 g/cm2) at ≥1 site had higher preoperative serum CTX, P1NP, and urine calcium concentrations than those without improvement.

CONCLUSION

Parathyroidectomy significantly improved BMD and remodeling biomarkers in women with osteopenia, thereby supporting the benefit of parathyroidectomy in these patients. Preoperative serum CTX and P1NP concentrations could be useful to predict expected BMD gain.

Systematic review of the risk of urolithiasis following parathyroidectomy in patients with primary hyperparathyroidism

OBJECTIVE

Parathyroidectomy (PTX) is the conclusive therapy for primary hyperparathyroidism (PHPT), but its effect on the risk of urolithiasis is inconclusive. We comprehensively reviewed the currently available research to investigate the impact of PTX on the likelihood of urolithiasis among individuals suffering PHPT.

METHODS

Internet-based articles in English language released on Cochrane, PubMed, Scopus, Web of knowledge, and Embase up to September, 2023 were comprehensively reviewed. Each publication in contrast to the incidence, occurrence, or recurrence of urolithiasis after PTX versus medical treatment in PHPT patients was included. The outcome with pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) was examined employing DerSimonian and Laird's model of random effects. To determine the range of the real effect size of a future study in 95% of all populations, a prediction interval (PI) was also established.

RESULTS

Finally, ten studies involving 74,190 patients were included. Results from randomized-controlled trials (RCTs) and observational studies (OSs) both revealed that PTX did not substantially lessen the vulnerability of urolithiasis among individuals with PHPT (RCTs: pooled relative risk [RR] 0.42, 95%CI 0.13-1.41, p = 0.163; OSs: pooled RR 1.37, 95%CI 0.96 to 1.97, p = 0.084). The PI (RCT: 0.03 to 5.96; OSs: 0.44-4.20) containing 1.0 suggested the possibility of consistent results in future studies. Subgroup and sensitivity analyses supported the above findings, and no evidence showed publication bias.

CONCLUSION

Our analysis from the available RCTs or OSs did not give adequate or exact proof that the average effect of PTX lowers the incidence of urolithiasis among PHPT persons based on the random-effects model. Future research shall take into account the common effect of PTX as well as the prerequisites of preventive stone procedures, which will further help us assess the effectiveness of PTX in reducing kidney calculus comorbidity and develop techniques to avoid stone sequelae in these individuals.

Regional variations in the management of primary hyperparathyroidism in Sweden: population-based case-control study

BACKGROUND

Substantial disparities in the utilization of parathyroidectomy for primary hyperparathyroidism have been reported. This study aimed to analyse regional variations in parathyroidectomy incidence with respect to the patient's disease burden and socioeconomic status.

METHODS

A population-based case-control study included all patients with primary hyperparathyroidism who underwent parathyroidectomy in Sweden between 2008 and 2017 and 10 matched controls. Data on demographic and socioeconomic variables, co-morbidities and drug prescriptions were collected from relevant national registers. Conditional logistic regression was used to analyse predictors of parathyroidectomy.

RESULTS

A total of 8626 patients with primary hyperparathyroidism (77% women) underwent parathyroidectomy during the study interval. The annual incidence of parathyroidectomy was 9.0 per 100 000 persons. The annual age-adjusted regional incidences of parathyroidectomy varied between 3.3 and 16.9 operations per 100 000 inhabitants. Except for a small underrepresentation of patients with lower education, no effect of socioeconomic variables was observed. Compared with matched controls, the parathyroidectomy group had increased odds ratios of having developed classical symptoms of primary hyperparathyroidism and being prescribed medication against cardiovascular disorders and psychiatric illness at the time of parathyroidectomy. Increased risks of kidney stones and osteoporosis were observed 5 years before parathyroidectomy. Patients with primary hyperparathyroidism selected for parathyroidectomy from regions with a low incidence of operations had a higher prevalence of kidney stones, osteoporosis and hypertension, as well as larger adenomas and higher calcium levels at the time of parathyroidectomy compared with patients in high-incidence regions.

CONCLUSION

The considerable variation in parathyroidectomy seems more likely associated with different clinical thresholds for detection of primary hyperparathyroidism and referral to surgery than socioeconomic disparities.

Parathyroidectomy and the Risk of Major Cerebrovascular and Cardiovascular Events in the Elderly

OBJECTIVE

We aimed to determine the incidence of major cardiovascular and cerebrovascular events in elderly patients with primary hyperparathyroidism (pHPT) and the impact of parathyroidectomy.

SUMMARY BACKGROUND DATA

pHPT is underdiagnosed and undertreated in the United States. It is associated with increased cardiovascular disease risk, but its association with cerebrovascular disease risk is not well-established. It is also unknown if parathyroidectomy reduces these risks.

METHODS

The incidence of major cerebrovascular and cardiovascular events in 108,869 patients with pHPT diagnosed in the Medicare database between 2008 and 2018 and a matched comparison group of 1,088,690 Medicare subjects was prospectively evaluated. We estimated hazard ratios (HR) for the association of pHPT and parathyroidectomy for the risk of these outcomes from Cox proportional hazards models. Survival curves were calculated to obtain 5-year disease-free survival estimates.

RESULTS

For patients with pHPT, five-year disease-free survival was lower, and HRs were higher than the comparison group for any outcome (75.9% vs. 78.4; HR 1.11, 95% confidence interval [CI] 1.09-1.13), major cerebrovascular events (84.5% vs. 86.3%; HR 1.14, 95% CI 1.12-1.17), and major cardiovascular events (87.7% vs. 88.8%; HR 1.06, 95% CI 1.03-1.08). However, in patients who had parathyroidectomy, the risks of major cerebrovascular and cardiovascular events did not differ from the comparison cohort. The lower risk in patients who had parathyroidectomy was maintained in subgroup analyses.

CONCLUSIONS

Older patients with pHPT have an increased risk of major cerebrovascular and cardiovascular events compared with patients without the disease. Physicians treating older patients with primary hyperparathyroidism should consider parathyroidectomy.R.M.P. and N.N. contributed equally to the preparation of this manuscript.

Primary Hyperparathyroidism and Cardiovascular Disease: An Association Study Using Clinical Natural Language Processing Systems and Big Data Analytics

Primary hyperparathyroidism (PHPT) seems to be associated with different cardiovascular diseases (CVDs). We evaluated the association of PHPT with major CV risk factors (CVRFs) and CVDs by using artificial intelligence (AI) tools. An observational and retrospective study was conducted using data from the electronic health records (EHRs) of the Hospital Universitario Puerta de Hierro Majadahonda (Spain). Of a total of 699,157 patients over 18 years of age studied (54.7% females), 6515 patients (0.9%; 65.4% women; mean age 67.6 ± 15.9 years) had a diagnosis of PHPT. The overall frequencies of hypertension, dyslipidemia, diabetes mellitus, and smoking habit in the cohort of patients with PTHP were all significantly (p < 0.001) higher than those found in patients without a diagnosis of PTHP. The total frequency of stroke, ischemic heart disease, atrial fibrillation, deep vein thrombosis, and pulmonary embolism in the cohort of PHPT patients were significantly (p < 0.001) higher than that found in patients without the diagnosis of PHPT. A multivariate regression analysis showed that PHPT was significantly (p < 0.001) and independently associated with all the CVDs evaluated. Our data show that there is a significant association between the diagnosis of PHPT and the main CVRFs and CVDs in our hospital population.

Molecular and Clinical Spectrum of Primary Hyperparathyroidism

Recent data suggest an increase in the overall incidence of parathyroid disorders, with primary hyperparathyroidism (PHPT) being the most prevalent parathyroid disorder. PHPT is associated with morbidities (fractures, kidney stones, chronic kidney disease) and increased risk of death. The symptoms of PHPT can be nonspecific, potentially delaying the diagnosis. Approximately 15% of patients with PHPT have an underlying heritable form of PHPT that may be associated with extraparathyroidal manifestations, requiring active surveillance for these manifestations as seen in multiple endocrine neoplasia type 1 and 2A. Genetic testing for heritable forms should be offered to patients with multiglandular disease, recurrent PHPT, young onset PHPT (age ≤40 years), and those with a family history of parathyroid tumors. However, the underlying genetic cause for the majority of patients with heritable forms of PHPT remains unknown. Distinction between sporadic and heritable forms of PHPT is useful in surgical planning for parathyroidectomy and has implications for the family. The genes currently known to be associated with heritable forms of PHPT account for approximately half of sporadic parathyroid tumors. But the genetic cause in approximately half of the sporadic parathyroid tumors remains unknown. Furthermore, there is no systemic therapy for parathyroid carcinoma, a rare but potentially fatal cause of PHPT. Improved understanding of the molecular characteristics of parathyroid tumors will allow us to identify biomarkers for diagnosis and novel targets for therapy.

Long-term effects of primary hyperparathyroidism and parathyroidectomy on kidney function

IMPORTANCE

Limited evidence supports kidney dysfunction as an indication for parathyroidectomy in asymptomatic primary hyperparathyroidism (PHPT).

OBJECTIVE

To investigate the natural history of kidney function in PHPT and whether parathyroidectomy alters renal outcomes.

DESIGN

Matched control study.

SETTING

A vertically integrated health care system serving 4.6 million patients in Southern California.

PARTICIPANTS

6058 subjects with PHPT and 16 388 matched controls, studied from 2000 to 2016.

EXPOSURES

Biochemically confirmed PHPT with varying serum calcium levels.

MAIN OUTCOMES

Estimated glomerular filtration rate (eGFR) trajectories were compared over 10 years, with cases subdivided by severity of hypercalcemia: serum calcium 2.62-2.74 mmol/L (10.5-11 mg/dL), 2.75-2.87 (11.1-11.5), 2.88-2.99 (11.6-12), and >2.99 (>12). Interrupted time series analysis was conducted among propensity-score-matched PHPT patients with and without parathyroidectomy to compare eGFR trajectories postoperatively.

RESULTS

Modest rates of eGFR decline were observed in PHPT patients with serum calcium 2.62-2.74 mmol/L (−1.0 mL/min/1.73 m2/year) and 2.75-2.87 mmol/L (−1.1 mL/min/1.73 m2/year), comprising 56% and 28% of cases, respectively. Compared with the control rate of −1.0 mL/min/1.73 m2/year, accelerated rates of eGFR decline were observed in patients with serum calcium 2.88-2.99 mmol/L (−1.5 mL/min/1.73 m2/year, P < .001) and >2.99 mmol/L (−2.1 mL/min/1.73 m2/year, P < .001), comprising 9% and 7% of cases, respectively. In the propensity score–matched population, patients with serum calcium >2.87 mmol/L exhibited mitigation of eGFR decline after parathyroidectomy (−2.0 [95% CI: −2.6 to −1.5] to −0.9 [95% CI: −1.5 to 0.4] mL/min/1.73 m2/year).

CONCLUSIONS AND RELEVANCE

Compared with matched controls, accelerated eGFR decline was observed in the minority of PHPT patients with serum calcium >2.87 mmol/L (11.5 mg/dL). Parathyroidectomy was associated with mitigation of eGFR decline in patients with serum calcium >2.87 mmol/L.

FCH-PET/CT in Primary Hyperparathyroidism With Discordant/Negative MIBI Scintigraphy and Ultrasonography

CONTEXT

The contribution of [18F]F-fluorocholine (FCH)-positron emission tomography (PET)/computed tomography (CT) in normocalcemic primary hyperparathyroidism (nPHPT) remains unknown.

OBJECTIVE

To evaluate the sensitivity and specificity of FCH-PET/CT in a cohort of osteoporotic patients with nPHPT and discordant or negative [99mTc]Tc-sestamibi scintigraphy and ultrasonography who all underwent parathyroidectomy (PTX).

DESIGN

Longitudinal retrospective cohort study in patients referred for osteoporosis with mild biological primary hyperparathyroidism.

SETTING

Tertiary referral center with expertise in bone metabolism and surgical management of hyperparathyroidism.

PATIENTS

Among 109 patients with PHPT analyzed, 3 groups were individualized according to total serum calcium (tCa) and ionized calcium (iCa): 32 patients with hypercalcemia (HtCa group), 39 patients with normal tCa and elevated iCa (NtCa group), and 38 patients with both normal tCa and iCa (NiCa). All patients had biochemical follow-up confirming or not the success of PTX.

MAIN OUTCOME MEASURES

To evaluate the performance of FCH-PET/CT in terms of sensitivity and specificity, and to compare with first-line imaging procedures in the setting of nPHPT.

RESULTS

The sensitivity of FCH-PET/CT was 67% in the hypercalcemic group, 48% in the NtCa group (P = .05 vs HtCa), and 33% in the NiCa group (P = .004 vs HtCa). Specificity ranged from 97% to 99%. FCH-PET/CT was positive in 64.3% of patients with negative conventional imaging, with biochemical resolution after PTX in 77.8% of patients. Triple negative imaging was observed in 20 patients, with PHPT resolution in 85% of these patients.

CONCLUSION

This study highlights the contribution of FCH-PET/CT in a well-phenotyped cohort of normocalcemic patients with discordant or negative findings in [99mTc]Tc-sestamibi scintigraphy and ultrasonography. However, negative imaging in nPHPT does not rule out the possibility of surgical cure by an experienced surgeon.

Comparison of Medical Management versus Parathyroidectomy in Patients with Mild Primary Hyperparathyroidism: A Meta-Analysis

BACKGROUND

Parathyroidectomy is the definitive cure for patients with primary hyperparathyroidism (pHPT) and has an annual prevalence of 0.2-1% in the United States. Some patients with mild disease are medically managed effectively using calcium-lowering medications and drugs against complications such as osteoporosis; however, many maintain a persistently high calcium level that negatively impacts their skeletal, renal, and psychogenic systems over the long term. This meta-analysis aims to compare the outcomes of medical management versus parathyroidectomy in patients with mild pHPT.

STUDY DESIGN

This meta-analysis was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using PubMed, Embase, and Web of Science by two teams of investigators. Analysis was run using R packages.

RESULTS

A total of 12 publications including seven randomized control, two prospective, and three retrospective trials with a total of 1346 patients were included for analysis. The average follow-up for all patients was 41 ± 23.8 months. Demographics, pre-treatment calcium, PTH, and bone mineral density (BMD) were similar between the medical (N = 632) and surgical (N = 714) cohorts. Post-treatment calcium and PTH levels were significantly higher in the medical cohort (10.46 vs. 9.39, p < 0.01), (106.14 vs. 43.25, p = 0.001), respectively. Interestingly, the post-treatment PTH in the medical cohort increased when compared to pre-treatment (83.84 to 106.14). Patients in the medical cohort had lower BMD in lumbar (0.48 g/cm²; OR = 0.42, 95% CI = 0.21, 0.83), femoral (0.48; OR = 0.42, 95% CI = 0.29, 0.61), and hip (0.61; OR = 0.33, 95% CI = 0.13, 0.85). Incidences of fracture, nephrolithiasis, cardiovascular death, or overall mortality were not significantly different between the cohorts.

CONCLUSIONS

The present study is the most comprehensive meta-analysis on mild pHPT to date. Our findings reflect that parathyroidectomy is the superior option in the treatment of mild pHPT patients as opposed to medical management.

Estimated Effect of Parathyroidectomy on Long-Term Kidney Function in Adults With Primary Hyperparathyroidism

BACKGROUND

Multidisciplinary guidelines recommend parathyroidectomy to slow the progression of chronic kidney disease in patients with primary hyperparathyroidism (PHPT) and an estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2. Limited data address the effect of parathyroidectomy on long-term kidney function.

OBJECTIVE

To compare the incidence of a sustained decline in eGFR of at least 50% among patients with PHPT treated with parathyroidectomy versus nonoperative management.

DESIGN

Target trial emulation was done using observational data from adults with PHPT, using an extended Cox model with time-varying inverse probability weighting.

SETTING

Veterans Health Administration.

PATIENTS

Patients with a new biochemical diagnosis of PHPT in 2000 to 2019.

MEASUREMENTS

Sustained decline of at least 50% from pretreatment eGFR.

RESULTS

Among 43 697 patients with PHPT (mean age, 66.8 years), 2928 (6.7%) had a decline of at least 50% in eGFR over a median follow-up of 4.9 years. The weighted cumulative incidence of eGFR decline was 5.1% at 5 years and 10.8% at 10 years in patients managed with parathyroidectomy, compared with 5.1% and 12.0%, respectively, in those managed nonoperatively. The adjusted hazard of eGFR decline did not differ between parathyroidectomy and nonoperative management (hazard ratio [HR], 0.98 [95% CI, 0.82 to 1.16]). Subgroup analyses found no heterogeneity of treatment effect based on pretreatment kidney function. Parathyroidectomy was associated with a reduced hazard of the primary outcome among patients younger than 60 years (HR, 0.75 [CI, 0.59 to 0.93]) that was not evident among those aged 60 years or older (HR, 1.08 [CI, 0.87 to 1.34]).

LIMITATION

Analyses were done in a predominantly male cohort using observational data.

CONCLUSION

Parathyroidectomy had no effect on long-term kidney function in older adults with PHPT. Potential benefits related to kidney function should not be the primary consideration for PHPT treatment decisions.

PRIMARY FUNDING SOURCE

National Institute on Aging.

[Localization diagnostics and operative strategy for the first intervention in sporadic primary hyperparathyroidism]

Primary hyperparathyroidism (pHPT) is a frequent endocrine disease, the incidence of which is clearly increasing. In addition to the classical symptoms of bone pain, osteoporosis and renal calculi, nonspecific complaints, such as listlessness and exhaustion, anxiety states and depressive symptoms also often occur. The diagnosis is simple and is carried out by determination of calcium and parathormone (PTH) serum levels. The majority of parathyroid adenomas can be localized by ultrasound and Tc-99m-MIBI scintigraphy. The indications for surgery can normally already be identified by the laboratory biochemical detection. Surgery is the only curative treatment of pHPT and is normally successful. In addition to bilateral exploration, a focused parathyroidectomy can be planned. The success of surgery can be intraoperatively documented by the determination of intraoperative Quick PTH (IOPTH).

Parathyroidectomy for adults with primary hyperparathyroidism

BACKGROUND

Primary hyperparathyroidism (PHPT), a disorder in which the parathyroid glands produce excessive amounts of parathyroid hormone, is most common in older adults and postmenopausal women. While most people with PHPT are asymptomatic at diagnosis, symptomatic disease can lead to hypercalcaemia, osteoporosis, renal stones, cardiovascular abnormalities and reduced quality of life. Surgical removal of abnormal parathyroid tissue (parathyroidectomy) is the only established treatment for adults with symptomatic PHPT to prevent exacerbation of symptoms and to be cured of PHPT. However, the benefits and risks of parathyroidectomy compared to simple observation or medical therapy for asymptomatic and mild PHPT are not well established.

OBJECTIVES

To evaluate the benefits and harms of parathyroidectomy in adults with PHPT compared to simple observation or medical therapy.

SEARCH METHODS

We searched CENTRAL, MEDLINE, LILACS, ClinicalTrials.gov and WHO ICTRP from their date of inception until 26 November 2021. We applied no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing parathyroidectomy with simple observation or medical therapy for the treatment of adults with PHPT.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. cure of PHPT, 2. morbidity related to PHPT and 3. serious adverse events. Our secondary outcomes were 1. all-cause mortality, 2. health-related quality of life and 3. hospitalisation for hypercalcaemia, acute renal impairment or pancreatitis. We used GRADE to assess the certainty of the evidence for each outcome.

MAIN RESULTS

We identified eight eligible RCTs that included 447 adults with (mostly asymptomatic) PHPT; 223 participants were randomised to parathyroidectomy. Follow-up duration varied from six months to 24 months. Of the 223 participants (37 men) randomised to surgery, 164 were included in the analyses, of whom 163 were cured at six to 24 months (overall cure rate 99%). Parathyroidectomy compared to observation probably results in a large increase in cure rate at six to 24 months follow-up: 163/164 participants (99.4%) in the parathyroidectomy group and 0/169 participants in the observation or medical therapy group were cured of their PHPT (8 studies, 333 participants; moderate certainty).  No studies explicitly reported intervention effects on morbidities related to PHPT, such as osteoporosis, osteopenia, kidney dysfunction, urolithiasis, cognitive dysfunction or cardiovascular disease, although some studies reported surrogate outcomes for osteoporosis and cardiovascular disease. A post-hoc analysis revealed that parathyroidectomy, compared to observation or medical therapy, may have little or no effect after one to two years on bone mineral density (BMD) at the lumbar spine (mean difference (MD) 0.03 g/cm2,95% CI -0.05 to 0.12; 5 studies, 287 participants; very low certainty). Similarly, compared to observation, parathyroidectomy may have little or no effect on femoral neck BMD after one to two years (MD -0.01 g/cm2, 95% CI -0.13 to 0.11; 3 studies, 216 participants; very low certainty). However, the evidence is very uncertain for both BMD outcomes. Furthermore, the evidence is very uncertain about the effect of parathyroidectomy on improving left ventricular ejection fraction (MD -2.38%, 95% CI -4.77 to 0.01; 3 studies, 121 participants; very low certainty). Four studies reported serious adverse events. Three of these reported zero events in both the intervention and control groups; consequently, we were unable to include data from these three studies in the pooled analysis. The evidence suggests that parathyroidectomy compared to observation may have little or no effect on serious adverse events (RR 3.35, 95% CI 0.14 to 78.60; 4 studies, 168 participants; low certainty).  Only two studies reported all-cause mortality. One study could not be included in the pooled analysis as zero events were observed in both the intervention and control groups. Parathyroidectomy compared to observation may have little or no effect on all-cause mortality, but the evidence is very uncertain (RR 2.11, 95% CI 0.20 to 22.60; 2 studies, 133 participants; very low certainty). Three studies measured health-related quality of life using the 36-Item Short Form Health Survey (SF-36) and reported inconsistent differences in scores for different domains of the questionnaire between parathyroidectomy and observation. Six studies reported hospitalisations for the correction of hypercalcaemia. Two studies reported zero events in both the intervention and control groups and could not be included in the pooled analysis. Parathyroidectomy, compared to observation, may have little or no effect on hospitalisation for hypercalcaemia (RR 0.91, 95% CI 0.20 to 4.25; 6 studies, 287 participants; low certainty). There were no reported hospitalisations for renal impairment or pancreatitis.

AUTHORS' CONCLUSIONS

In accordance with the literature, our review findings suggest that parathyroidectomy, compared to simple observation or medical (etidronate) therapy, probably results in a large increase in cure rates of PHPT (with normalisation of serum calcium and parathyroid hormone levels to laboratory reference values). Parathyroidectomy, compared with observation, may have little or no effect on serious adverse events or hospitalisation for hypercalcaemia, and the evidence is very uncertain about the effect of parathyroidectomy on other short-term outcomes, such as BMD, all-cause mortality and quality of life. The high uncertainty of evidence limits the applicability of our findings to clinical practice; indeed, this systematic review provides no new insights with regard to treatment decisions for people with (asymptomatic) PHPT. In addition, the methodological limitations of the included studies, and the characteristics of the study populations (mainly comprising white women with asymptomatic PHPT), warrant caution when extrapolating the results to other populations with PHPT. Large-scale multi-national, multi-ethnic and long-term RCTs are needed to explore the potential short- and long-term benefits of parathyroidectomy compared to non-surgical treatment options with regard to osteoporosis or osteopenia, urolithiasis, hospitalisation for acute kidney injury, cardiovascular disease and quality of life.

Primary hyperparathyroidism and fracture probability

The incidence of hip and major osteoporotic fracture was increased in patients with primary hyperparathyroidism even in patients not referred for parathyroidectomy. The risk of death was also increased which attenuated an effect on fracture probabilities. The findings argue for widening the indications for parathyroidectomy in mild primary hyperparathyroidism.

INTRODUCTION

Primary hyperparathyroidism (PHPT) is associated with an increase in the risk of fracture. In FRAX, the increase in risk is assumed to be mediated by low bone mineral density (BMD). However, the risk of death is also increased and its effect on fracture probability is not known.

OBJECTIVE

The aim of this study was to determine whether PHPT affects hip fracture and major osteoporotic fracture risk independently of bone mineral density (BMD) and whether this and any increase in mortality affects the assessment of fracture probability.

METHODS

A register-based survey of patients with PHPT and matched controls in Denmark were identified from hospital registers. The incidence of death, hip fracture, and major osteoporotic fracture were determined for computing fracture probabilities excluding time after parathyroidectomy. The gradient of risk for fracture for differences in BMD was determined in a subset of patients and in BMD controls. The severity of disease was based on serum calcium and parathyroid hormone levels.

RESULTS

We identified 6884 patients with biochemically confirmed PHPT and 68,665 matched population controls. On follow-up, excluding time after parathyroidectomy in those undergoing surgery, patients with PHPT had a higher risk of death (+52%), hip fracture (+48%), and major osteoporotic fracture (+36%) than population controls. At any given age, average 10-year probabilities of fracture were higher in patients with PHPT than population controls. The gradient of fracture risk with differences in BMD was similar in cases and controls. Results were similar when confined to patients not undergoing parathyroidectomy. Fracture probability decreased with the severity of disease due to an increase in mortality rather than fracture risk.

CONCLUSION

The risk of hip and other major osteoporotic fracture is increased in PHPT irrespective of the disease severity. Fracture probability was attenuated due to the competing effect of mortality. The increased fracture risk in patients treated conservatively argues for widening the indications for parathyroidectomy in mild PHPT.

Positive Effect of Parathyroidectomy Compared to Observation on BMD in a Randomized Controlled Trial of Mild Primary Hyperparathyroidism

Mild or asymptomatic disease is now the dominating presentation of primary hyperparathyroidism (PHPT). However, bone involvement with decreased bone mineral density (BMD) and an increased risk of fractures has been demonstrated. Indications for parathyroidectomy (PTX) in mild PHPT have been debated for years. There is a need of long-term randomized studies comparing PTX with observation without intervention (OBS). Here, we present bone health data from the Scandinavian Investigation of Primary Hyperparathyroidism (SIPH), a randomized controlled trial, comparing PTX to OBS. This study included 191 patients (96 OBS/95 PTX), and 129 patients (64 OBS/65 PTX) were followed for 10 years to the end of study (EOS). BMD was measured with dual-energy X-ray absorptiometry (DXA), peripheral fractures were noted, and spine radiographs were obtained for vertebral fracture assessment. There was a significant treatment effect of PTX on BMD compared with OBS for all analyzed compartments, most explicit for the lumbar spine (LS) and femoral neck (FN) (p < 0.001). The mean changes in T-score from baseline to 10 years were from 0.41 for radius 33% (Rad33) to 0.58 for LS greater in the PTX group than in the OBS group. There was a significant decrease in BMD for all compartments in the OBS group, most pronounced for FN, Rad33, and ultradistal radius (UDR) (p < 0.001). Even though there was a significant treatment effect of PTX compared with OBS, there was only a significant increase in BMD over time for LS (p < 0.001). We found no difference between groups in fracture frequency in the 10-year cohort, neither with modified intention-to-treat (mITT) analysis nor per protocol analysis. Because BMD is only a surrogate endpoint of bone health and PTX did not reduce fracture risk, observation could be considered a safe option for many patients with mild PHPT regarding bone health in a 10-year perspective. © 2023 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 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.

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.

Questionable value of [99mTc]-sestamibi scintigraphy in patients with pHPT and negative ultrasound

PURPOSE

A successful focused surgical approach in primary hyperparathyroidism (pHPT) relies on accurate preoperative localization of the parathyroid adenoma (PA). Most often, ultrasound is followed by [^99mTc]-sestamibi scintigraphy, but the value of this approach is disputed. Here, we evaluated the diagnostic approach in patients with surgically treated pHPT in our center with the aim to further refine preoperative diagnostic procedures.

METHODS

A single-center retrospective analysis of patients with pHPT from 01/2005 to 08/2021 was carried out followed by evaluation of the preoperative imaging modalities to localize PA. The localization of the PA had to be confirmed intraoperatively by the fresh frozen section and significant dropping of the intraoperative parathyroid hormone (PTH) levels.

RESULTS

From 658 patients diagnosed with pHPT, 30 patients were excluded from the analysis because of surgery for recurrent or persistent disease. Median age of patients was 58.0 (13-93) years and 71% were female. Neck ultrasound was carried out in 91.7% and localized a PA in 76.6%. In 23.4% (135/576) of the patients, preoperative neck ultrasound did not detect a PA. In this group, [^99mTc]-sestamibi correctly identified PA in only 25.4% of patients. In contrast, in the same cohort, the use of [¹¹C]-methionine or [¹¹C]-choline PET resulted in the correct identification of PA in 79.4% of patients (OR 13.23; 95% CI 5.24-33.56).

CONCLUSION

[¹¹C]-Methionine or [¹¹C]-choline PET/CT are superior second-line imaging methods to select patients for a focused surgical approach when previous ultrasound failed to identify PA.