Comparison of Seated With Recumbent Saline Suppression Testing for the Diagnosis of Primary Aldosteronism

A 120-Minute Saline Infusion Test for the Confirmation of Primary Aldosteronism: A Pilot Study

BACKGROUND

The saline infusion test (SIT) to confirm primary aldosteronism requires infusing 2 L of normal saline over 240 minutes. Previous studies raised concerns regarding increased blood pressure and worsening hypokalemia during SIT. We aimed to evaluate the diagnostic applicability of a SIT that requires 1 L of saline infusion over 120 minutes.

METHODS

A cross-sectional study, including all patients in a large medical center who underwent SIT from 1 January 2015 to 30 April 2023. Blood samples were drawn for baseline renin and aldosterone (t = 0) after 2 hours (t = 120 min) and after 4 hours (t = 240 min) of saline infusion. We used ROC analysis to evaluate the sensitivity and specificity of various aldosterone cut-off values at t = 120 to confirm primary aldosteronism.

RESULTS

The final analysis included 62 patients. A ROC analysis yielded 97% specificity and 90% sensitivity for a plasma aldosterone concentration (PAC) of 397 pmol/L (14 ng/dL) at t = 120 to confirm primary aldosteronism, and an area under the curve of 0.97 (95% CI [0.93, 1.00], P < 0.001). Almost half (44%) of the patients did not suppress PAC below 397 pmol/L (14 ng/dL) at t = 120. Of them, only one (4%) patient suppressed PAC below 276 pmol/L (10 ng/dL) at t = 240. Mean systolic blood pressure increased from 140.1 ± 21.3 mm Hg at t = 0 to 147.6 ± 14.5 mm Hg at t = 240 (P = 0.011).

CONCLUSIONS

A PAC of 397 pmol/L (14 ng/dL) at t = 120 has high sensitivity and specificity for primary aldosteronism confirmation.

Screening for Primary Aldosteronism by Mass Spectrometry Versus Immunoassay Measurements of Aldosterone: A Prospective Within-Patient Study

BACKGROUND

Measurements of aldosterone by mass spectrometry are more accurate and less prone to interferences than immunoassay measurements, and may produce a more accurate aldosterone:renin ratio (ARR) when screening for primary aldosteronism (PA).

METHODS

Differences in diagnostic performance of the ARR using mass spectrometry vs immunoassay measurements of aldosterone were examined in 710 patients screened for PA. PA was confirmed in 153 patients and excluded in 451 others. Disease classifications were not achieved in 106 patients. Areas under receiver-operating characteristic curves (AUROC) and other measures were used to compare diagnostic performance.

RESULTS

Mass spectrometry-based measurements yielded lower plasma aldosterone concentrations than immunoassay measurements. For the ARR based on immunoassay measurements of aldosterone, AUROCs were slightly lower (P = 0.018) than those using mass spectrometry measurements (0.895 vs 0.906). The cutoff for the ARR to reach a sensitivity of 95% was 30 and 21.5 pmol/mU by respective immunoassay and mass spectrometry-based measurements, which corresponded to specificities of 57% for both. With data restricted to patients with unilateral PA, diagnostic sensitivities of 94% with specificities >81% could be achieved at cutoffs of 61 and 52 pmol/mU for respective immunoassay and mass spectrometry measurements.

CONCLUSIONS

Mass spectrometry-based measurements of aldosterone for the ARR provide no clear diagnostic advantage over immunoassay-based measurements. Both approaches offer limited diagnostic accuracy for the ARR as a screening test. One solution is to employ the higher cutoffs to triage patients likely to have unilateral PA for further tests and possible adrenalectomy, while using the lower cutoffs to identify others for targeted medical therapy.German Clinical Trials Register ID: DRKS00017084.

The role of confirmatory tests in the diagnosis of primary aldosteronism

Confirmatory tests for diagnosis of primary aldosteronism (PA) play an important role in sparing patients with a false-positive aldosterone-to-renin ratio (ARR) screening test from undergoing invasive subtyping procedures. We recommend that patients with a positive ARR test should undergo at least one confirmatory test to confirm or exclude the diagnosis of PA before directly proceeding to subtype studies, except for patients with significant PA phenotypes, including spontaneous hypokalemia, plasma aldosterone concentration >20 ng/dL plus plasma renin activity below a detectable level. Although a gold standard confirmatory test has not been identified, we recommend that saline infusion test and captopril challenge test, which were widely used in Taiwan. Patients with PA have been reported to have a higher prevalence of concurrent autonomous cortisol secretion (ACS). ACS is a biochemical condition of mild cortisol overproduction from adrenal lesions, but without the typical clinical features of overt Cushing's syndrome. Concurrent ACS may result in incorrect interpretation of adrenal venous sampling (AVS) and may lead to adrenal insufficiency after adrenalectomy. We recommend screening for ACS in patients with PA scheduled for AVS examinations as well as for adrenalectomy. We recommend the 1-mg overnight dexamethasone suppression test as screening method to detect ACS.

Diagnosis and management of primary hyperaldosteronism in patients with hypertension: a practical approach endorsed by the British and Irish Hypertension Society

Alongside the lack of homogeneity among international guidelines and consensus documents on primary hyperaldosteronism, the National UK guidelines on hypertension do not provide extensive recommendations regarding the diagnosis and management of this condition. Local guidelines vary from area to area, and this is reflected in the current clinical practice in the UK. In an attempt to provide support to the clinicians involved in the screening of subjects with hypertension and clinical management of suspected cases of primary hyperaldosteronism the following document has been prepared on the behalf of the BIHS Guidelines and Information Service Standing Committee. Through remote video conferences, the authors of this document reviewed an initial draft which was then circulated among the BIHS Executive members for feedback. A survey among members of the BIHS was carried out in 2022 to assess screening strategies and clinical management of primary hyperaldosteronism in the different regions of the UK. Feedback and results of the survey were then discussed and incorporated in the final document which was approved by the panel after consensus was achieved considering critical review of existing literature and expert opinions. Grading of recommendations was not performed in light of the limited available data from properly designed randomized controlled trials.

Cost-effectiveness of screening for primary aldosteronism in hypertensive patients in Australia: a Markov modelling analysis

BACKGROUND

Primary aldosteronism affects 3-14% of hypertensive patients in the primary care setting and up to 30% in the hypertensive referral units. Although primary aldosteronism screening is recommended in patients with treatment-resistant hypertension, diagnosis at an earlier stage of disease may prevent end-organ damage and optimize patient outcomes.

METHODS

A Markov model was used to estimate the cost-effectiveness of screening for primary aldosteronism in treatment and disease (cardiovascular disease and stroke) naive hypertensive patients. Within the model, a 40-year-old patient with hypertension went through either the screened or the unscreened arm of the model. They were followed until age 80 or death. In the screening arm, the patient underwent standard diagnostic testing for primary aldosteronism if the screening test, aldosterone-to-renin ratio, was elevated above 70 pmol/l : mU/l. Diagnostic accuracies, transition probabilities and costs were derived from published literature and expert advice. The main outcome of interest was the incremental cost effectiveness ratio (ICER).

RESULTS

Screening hypertensive patients for primary aldosteronism compared with not screening attained an ICER of AU$35 950.44 per quality-adjusted life year (QALY) gained. The results were robust to different sensitivity analyses. Probabilistic sensitivity analysis demonstrated that in 73% of the cases, it was cost-effective to screen at the commonly adopted willingness-to-pay (WTP) threshold of AU$50 000.

CONCLUSION

The results from this study demonstrated that screening all hypertensive patients for primary aldosteronism from age 40 is cost-effective. The findings argue in favour of screening for primary aldosteronism before the development of severe hypertension in the Australian healthcare setting.

Underdiagnosis of Primary Aldosteronism: A Review of Screening and Detection

A clinical condition may be missed due to its higher-than-recognized prevalence or inadequate diagnostic screening. Both factors apply to primary aldosteronism, which is woefully underdiagnosed as a cause of hypertension and end-organ damage. Screening tests should be strongly considered for diseases that pose significant morbidity or mortality if left untreated, that have a high prevalence, and that have treatments that lead to improvement or cure. In this review we present the evidence for each of these points. We outline studies that estimate the prevalence of primary aldosteronism in different at-risk populations and how its recognition has changed over time. We also evaluate myriad studies of screening rates for primary aldosteronism and what factors do and do not influence current screening practices. We discuss the ideal conditions for screening, measuring the aldosterone to renin ratio in different populations that use plasma renin activity or direct renin concentration, and the steps for diagnostic workup of primary aldosteronism. Finally, we conclude with potential strategies to implement higher rates of screening and diagnosis of this common, consequential, and treatable disease.

Exclusion Tests in Unilateral Primary Aldosteronism (ExcluPA) Study

CONTEXT

Determining the diagnostic accuracy of "exclusion" tests for primary aldosteronism (PA) compared to the aldosterone to renin ratio (ARR) is fundamental to avoid invasive subtyping in false-positive patients at screening.

OBJECTIVE

To assess the accuracy of exclusion tests for PA using the diagnosis of unilateral PA as reference.

METHODS

PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched for studies published from January 1, 1970, to December 31, 2021, meeting tight quality criteria. Data were extracted following the PRISMA methodology. We performed a two-stage meta-analysis that entailed an exploratory and a validation phase based on a "golden" or "gold" diagnostic standard, respectively. Pooled specificity, negative likelihood ratio, diagnostic odds ratio, and summary area under the ROC curve (sAUROC) were calculated to analyze the accuracy of exclusion tests.

RESULTS

A meta-analysis of 31 datasets comprising a total of 4242 patients fulfilling the predefined inclusion criteria found that pooled accuracy estimates (sAUROC) did not differ between the ARR (0.95; 95% CI, 0.92-0.98), the captopril challenge test (CCT) (0.92; 95% CI, 0.88-0.97), and the saline infusion test (SIT) (0.96; 95% CI, 0.94-0.99). Solid information could not be obtained for the fludrocortisone suppression test and the furosemide upright test, which were assessed in only 1 study each.

CONCLUSION

The apparently high diagnostic accuracy of the CCT and the SIT was due to the selection of patients with an elevated ARR and thus a high pretest probability of unilateral PA; however, neither test furnished a diagnostic gain over the ARR. Therefore, the systematic use of these exclusion tests in clinical practice is not justified by available evidence.

Saline suppression to distinguish the primary aldosteronism subtype: a diagnostic study

OBJECTIVES

The saline suppression test (SST) serves to confirm the diagnosis of primary aldosteronism (PA), while adrenal vein sampling (AVS) is used to subtype PA as unilateral or bilateral. Criteria that can accurately identify those with bilateral PA based on SST results could reduce the need for AVS. We previously demonstrated that a combination of plasma aldosterone concentration (PAC) < 300 pmol L-1 and a reduction in aldosterone-to-renin ratio (ARR) following recumbent SST had high specificity for predicting bilateral PA in an Australian cohort of 92 patients with PA who have undergone AVS. We sought to validate our predictive criteria in larger, independent cohorts of patients with PA.

DESIGN

An international, multi-centre cohort study.

METHODS

Data from 55 patients at Monash Health, Victoria, Australia, 106 patients from the First Affiliated Hospital of Chongqing Medical University, China, and 105 patients from Nihon University Itabashi Hospital, Japan were analysed.

RESULTS

A combination of PAC <300 pmol L-1 and a reduction in ARR following recumbent SST predicted bilateral PA with specificities of 88.2%, 97.0%, and 100.0% in Australian, Chinese, and Japanese cohorts, respectively. This criterion could allow 22%-38% of patients with PA to bypass AVS and proceed directly to medical treatment.

CONCLUSION

In patients undergoing the recumbent SST, a post-saline PAC <300 pmol L-1 together with a reduction in ARR can predict bilateral PA with high specificity and may allow targeted treatment to be commenced without AVS in up to a third of patients.

Aldosterone, Renin, and Aldosterone-to-Renin Ratio Variability in Screening for Primary Aldosteronism

CONTEXT

The plasma aldosterone concentration (PAC), renin, and aldosterone-to-renin ratio (ARR) are used to screen for primary aldosteronism (PA). Substantial intra-individual variability of PAC and ARR using plasma renin activity in the context of usual antihypertensive therapy has been described, but there is no data on ARR variability calculated using direct renin concentration (DRC).

OBJECTIVE

To describe the intra-individual variability of PAC, DRC, and ARR in the absence of interfering medications in patients with and without PA.

DESIGN

Retrospective cohort study.

PATIENTS

Hypertensive patients referred for investigation of PA, with at least 2 ARR measurements while off interfering medications.

SETTING

Endocrine hypertension service of a tertiary center, from May 2017 to July 2021.

MAIN OUTCOME MEASURES

PAC, DRC, and ARR variability was calculated as coefficient of variation (CV) and percent difference (PD).

RESULTS

Analysis of 223 patients (55% female, median age 52 years), including 162 with confirmed PA, demonstrated high variability with a sample CV of 22-25% in the PAC and sample CV of 41% to 42% in the DRC and ARR in both the PA and non-PA groups. The degree of variability was substantially higher than the assays' analytical CV. Sixty-two patients (38%) with PA had at least one ARR below 70 pmol/L:mU/L (2.4 ng/dL:mU/L), a cut-off for first-line screening of PA.

CONCLUSIONS

Significant intra-individual variability in PAC, DRC, and hence ARR occurs in a large proportion of patients being investigated for PA. These findings support the need for at least 2 ARR before PA is excluded or further investigated.

First survey on the diagnosis and treatment of primary aldosteronism by Spanish Endocrinology and Nutrition specialists

OBJECTIVE

To evaluate the indication and the resources for the screening/diagnosis of primary aldosteronism (PA) in Endocrinology units in Spain.

MATERIAL AND METHODS

An anonymous 2-phase (2020/2021) online survey was conducted by the AdrenoSEEN group among SEEN members with data about screening, confirmation tests, availability of catheterisation and the treatment of PA.

RESULTS

Eighty-eight (88) specialists completed the survey. Plasma aldosterone concentration and plasma renin activity were available at all centres; urinary aldosterone was available in 55% of them. The most frequent indications for determining the aldosterone/renin ratio (ARR) were adrenal incidentaloma (82.6%), hypertension with hypokalaemia (82.6%), hypertension in patients <40 years (79.1%) and a family history of PA (77.9%). 61% and 18% of the respondents used an ARR cut-off value of PA of ≥30 and 20ng/dl per ng/mL/, respectively. The intravenous saline loading test was the most commonly used confirmatory test (66.3%), followed by the captopril challenge test (24.4%), with the 25mg dose used more than the 50mg dose (65% versus 35%). 67.4% of the participants confirmed the availability of adrenal vein catheterization (AVC). 41% of this subgroup perform it with a continuous infusion versus 30.5% with an ACTH (1-24) bolus, whereas 70.3% employ sequential adrenal vein catheterization. 48% of the participants reported an AVC success <50%. Total laparoscopic adrenalectomy was the treatment of choice (90.6%), performed by specialists in General and Digestive Surgery specialising in endocrinological pathology.

CONCLUSION

PA screening and diagnostic tests are extensively available to Spanish endocrinologists. However, there is a major variability in their use and in the cut-off points of the diagnostic methods. The AVS procedure remains poorly standardised and is far from delivering optimal performance. Greater standardisation in the study and diagnosis of PA is called for.

Primary Aldosteronism: State-of-the-Art Review

We are witnessing a revolution in our understanding of primary aldosteronism (PA). In the past 2 decades, we have learned that PA is a highly prevalent syndrome that is largely attributable to pathogenic somatic mutations, that contributes to cardiovascular, metabolic, and kidney disease, and that when recognized, can be adequately treated with widely available mineralocorticoid receptor antagonists and/or surgical adrenalectomy. Unfortunately, PA is rarely diagnosed, or adequately treated, mainly because of a lack of awareness and education. Most clinicians still possess an outdated understanding of PA; from primary care physicians to hypertension specialists, there is an urgent need to redefine and reintroduce PA to clinicians with a modern and practical approach. In this state-of-the-art review, we provide readers with the most updated knowledge on the pathogenesis, prevalence, diagnosis, and treatment of PA. In particular, we underscore the public health importance of promptly recognizing and treating PA and provide pragmatic solutions to modify clinical practices to achieve this.

A Novel ARMC5 Germline Variant in Primary Macronodular Adrenal Hyperplasia Using Whole-Exome Sequencing

Background: Primary macronodular adrenocortical hyperplasia (PMAH) is a rare form of adrenal Cushing’s syndrome with incomplete penetrance which may be sporadic or autosomal dominant. The inactivation of the ARMC5 gene, a potential tumor suppressor gene, is one of the associated causes of PMAH. This study aimed to identify the variant responsible for Iranian familial PMAH. Methods: The proband, a 44-year-old woman, was directed to whole-exome sequencing (WES) of the blood sample to discover a germline variant. In addition, the identified causative variant was confirmed and segregated in other and available unaffected family members. Results: The novel germline heterozygous missense variant, c.2105C>A in the ARMC5 gene, was found, and the same germline variant as the proband was confirmed in two affected sisters. This variant was detected in the brother of the proband with an asymptomatic condition and this considered because of incomplete penetrance and age-dependent appearance. The function of the ARMC5 protein would be damaged by the identified variant, according to in silico and computer analyses that followed. Conclusion: The new germline ARMC5 variation (c.2105C>A, (p. Ala702Glu)) was interpreted as a likely pathogenic variant based on ACMG and Sherloc standards. PMAH may be diagnosed early using genetic testing that shows inherited autosomal dominant mutations in the ARMC5 gene.

Aldosterone Immunoassay-Specific Cutoff Value for Seated Saline Suppression Test for Diagnosing Primary Aldosteronism

A seated saline loading test (SLT) using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is one of the most accepted confirmatory tests of primary aldosteronism. However, LC-MS/MS is time-consuming and is not widely available in diagnostic laboratories compared to immunoassay. With immunoassay, it is unknown whether SLT in the seated position is more accurate than that of the supine position, and a cutoff value of post-seated SLT plasma aldosterone concentration (PAC) must be established in the Korean population. Ninety-eight patients underwent SLT in both positions, and post-SLT PAC was measured by LC-MS/MS and radioimmunoassay. We confirmed primary aldosteronism if post-seated SLT PAC by LC-MS/MS exceeded 5.8 ng/dL. The area under the receiver operating characteristic curve was greater for seated than supine SLT (0.928 vs. 0.834, P=0.003). The optimal cutoff value of post-seated SLT by radioimmunoassay was 6.6 ng/dL (sensitivity 83.3%, specificity 92.2%).

Primary aldosteronism - a multidimensional syndrome

Primary aldosteronism is a common cause of hypertension and is a risk factor for cardiovascular and renal morbidity and mortality, via mechanisms mediated by both hypertension and direct insults to target organs. Despite its high prevalence and associated complications, primary aldosteronism remains largely under-recognized, with less than 2% of people in at-risk populations ever tested. Fundamental progress made over the past decade has transformed our understanding of the pathogenesis of primary aldosteronism and of its clinical phenotypes. The dichotomous paradigm of primary aldosteronism diagnosis and subtyping is being redefined into a multidimensional spectrum of disease, which spans subclinical stages to florid primary aldosteronism, and from single-focal or multifocal to diffuse aldosterone-producing areas, which can affect one or both adrenal glands. This Review discusses how redefining the primary aldosteronism syndrome as a multidimensional spectrum will affect the approach to the diagnosis and subtyping of primary aldosteronism.

Performance of Confirmatory Tests for Diagnosing Primary Aldosteronism: a Systematic Review and Meta-Analysis

Background:

Confirmatory tests are recommended for diagnosing primary aldosteronism, but the supporting evidence is unclear.

Methods:

We searched Medline, EMBASE, and the Cochrane Central Register of Controlled Trials. Studies evaluating any guideline-recommended confirmatory test (ie, saline infusion test, salt loading test, fludrocortisone suppression test, and captopril challenge test), compared with a reference standard were included. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess the risk of bias. Meta-analyses were conducted using hierarchical summary receiver operating characteristic models.

Results:

Fifty-five studies were included, comprising 26 studies (3654 participants) for the recumbent saline infusion test, 4 studies (633 participants) for the seated saline infusion test, 2 studies (99 participants) for the salt loading test, 7 studies (386 participants) for the fludrocortisone suppression test, and 25 studies (2585 participants) for the captopril challenge test. Risk of bias was high, affecting more than half of studies, and across all domains. Studies with case-control sampling overestimated accuracy by 7-fold (relative diagnostic odds ratio, 7.26 [95% CI, 2.46–21.43]) and partial verification or use of inconsistent reference standards overestimated accuracy by 5-fold (5.12 [95% CI, 1.48–17.77]). There were large variations in how confirmatory tests were conducted, interpreted, and verified. Under most scenarios, confirmatory testing resulted in an excess of missed cases. The certainty of evidence underlying each test (Grading of Recommendations, Assessment, Development, and Evaluations) was very low.

Conclusions:

Recommendations for confirmatory testing in patients with abnormal screening tests and high probability features of primary aldosteronism are based on very low-quality evidence and their routine use should be reconsidered.

Validation of three novel clinical prediction tools for primary aldosteronism subtyping

The 20-point clinical prediction SPACE score, the aldosterone-to-lowest potassium ratio (APR), aldosterone concentration (AC) and the AC relative reduction rate after saline infusion test (SIT) have recently been proposed for primary aldosteronism (PA) subtyping prior to adrenal vein sampling (AVS). To validate those claims, we performed a retrospective cross-sectional study that included all patients at our center who had positive SIT to confirm PA and were diagnosed with either bilateral disease (BPA) according to AVS or with lateralized disease (LPA) if biochemically cured after adrenalectomy from November 2004 to the end of 2019. Final diagnoses were used to evaluate the diagnostic performance of proposed clinical prediction tools. Our cohort included 144 patients (40 females), aged 32-72 years (mean 54 years); 59 with LPA and 85 with BPA. The originally suggested SPACE score ≤8 and SPACE score >16 rules yielded about 80% positive predictive value (PPV) for BPA and LPA, respectively. Multivariate analyses with the predictors constituting the SPACE score highlighted post-SIT AC as the most important predictor of PA subtype for our cohort. APR-based tool of <5 for BPA and >15 for LPA yielded about 75% PPV for LPA and BPA. The proposed post-SIT AC <8.79 ng/dL criterion yielded 41% sensitivity and 90% specificity, while the relative post-SIT AC reduction rate of >33.8% criterion yielded 80% sensitivity and 51% specificity for BPA prediction. The application of any of the validated clinical prediction tools to our cohort did not predict the PA subtype with the high diagnostic performance originally reported.

Detecting primary aldosteronism in Australian primary care: a prospective study

OBJECTIVE

To assess the identification of primary aldosteronism (PA) in newly diagnosed, treatment-naïve patients with hypertension by screening in primary care.

DESIGN

Prospective study.

SETTING

General practices in the South Eastern Melbourne Primary Health Network with at least three general practitioners and general practices elsewhere in Victoria that had referred patients to the Endocrine Hypertension Clinic at Monash Health, 2017-2020.

PARTICIPANTS

Adults (18-80 years) with newly diagnosed hypertension (measurements of systolic blood pressure > 140 mmHg or diastolic blood pressure > 90 mmHg on at least two occasions) and not taking antihypertensive medications were screened for PA by assessing their aldosterone-to-renin ratio (ARR). Participants with two ARR values exceeding 70 pmol/mU underwent saline suppression testing at the Endocrine Hypertension Service (Monash Health) to confirm the diagnosis of PA.

MAIN OUTCOME MEASURES

Prevalence of PA (number of patients with confirmed PA divided by number screened).

RESULTS

Sixty-two of 247 screened participants had elevated ARR values on screening (25%); for 35 people (14%; 95% CI, 10-19%), PA was confirmed by saline suppression testing. Baseline characteristics (mean age, sex distribution, median baseline blood pressure levels, and serum potassium concentration) were similar for people with or without PA.

CONCLUSION

PA was diagnosed in 14% of patients with newly diagnosed hypertension screened by GPs, indicating a potential role for GPs in the early detection of an important form of secondary hypertension for which specific therapies are available.

Poor Performance of Angiotensin II Enzyme-Linked Immuno-Sorbent Assays in Mostly Hypertensive Cohort Routinely Screened for Primary Aldosteronism

Primary aldosteronism (PA) is the most common, but broadly underdiagnosed, form of hormonal hypertension. To improve screening procedures, current biochemical approaches aim to determine newly appreciated angiotensin II (Ang II) and calculate the aldosterone-to-angiotensin II ratio (AA2R). Thus, the aim of this study was to assess the diagnostic performance of these screening tests in comparison to the aldosterone-to-direct renin ratio (ADRR), which is routinely used. Cheap and available ELISA was used for Ang II measurement. To our knowledge, this is the first study of this laboratory method’s usage in PA. The study cohort included 20 PA patients and 80 controls. Ang II concentrations were comparable between PA and non-PA patients (773.5 vs. 873.2 pg/mL, p = 0.23, respectively). The AA2R was statistically significantly higher in PA group when compared with non-PA (0.024 vs. 0.012 ng/dL/pg/mL, p < 0.001). However, the diagnostic performance of the AA2R was significantly worse than that of the ADRR (AUROC 0.754 vs. 0.939, p < 0.01). The sensitivity and specificity of the AA2R were 70% and 76.2%, respectively. Thus, the AA2R was not effective as a screening tool for PA. Our data provide important arguments in the discussion on the unsatisfactory accuracy of renin−angiotensin system evaluation by recently repeatedly used ELISA tests.

Japan Endocrine Society clinical practice guideline for the diagnosis and management of primary aldosteronism 2021

Primary aldosteronism (PA) is associated with higher cardiovascular morbidity and mortality rates than essential hypertension. The Japan Endocrine Society (JES) has developed an updated guideline for PA, based on the evidence, especially from Japan. We should preferentially screen hypertensive patients with a high prevalence of PA with aldosterone to renin ratio ≥200 and plasma aldosterone concentrations (PAC) ≥60 pg/mL as a cut-off of positive results. While we should confirm excess aldosterone secretion by one positive confirmatory test, we could bypass patients with typical PA findings. Since PAC became lower due to a change in assay methods from radioimmunoassay to chemiluminescent enzyme immunoassay, borderline ranges were set for screening and confirmatory tests and provisionally designated as positive. We recommend individualized medicine for those in the borderline range for the next step. We recommend evaluating cortisol co-secretion in patients with adrenal macroadenomas. Although we recommend adrenal venous sampling for lateralization before adrenalectomy, we should carefully select patients rather than all patients, and we suggest bypassing in young patients with typical PA findings. A selectivity index ≥5 and a lateralization index >4 after adrenocorticotropic hormone stimulation defines successful catheterization and unilateral subtype diagnosis. We recommend adrenalectomy for unilateral PA and mineralocorticoid receptor antagonists for bilateral PA. Systematic as well as individualized clinical practice is always warranted. This JES guideline 2021 provides updated rational evidence and recommendations for the clinical practice of PA, leading to improved quality of the clinical practice of hypertension.

The Saline Infusion Test for Primary Aldosteronism: Implications of Immunoassay Inaccuracy

CONTEXT

Diagnosis of primary aldosteronism (PA) for many patients depends on positive results for the saline infusion test (SIT). Plasma aldosterone is often measured by immunoassays, which can return inaccurate results.

OBJECTIVE

This study aimed to establish whether differences in aldosterone measurements by immunoassay versus mass spectrometry (MS) might impact confirmatory testing for PA.

METHODS

This study, involving 240 patients tested using the SIT at 5 tertiary care centers, assessed discordance between immunoassay and MS-based measurements of plasma aldosterone.

RESULTS

Plasma aldosterone measured by Liaison and iSYS immunoassays were respectively 86% and 58% higher than determined by MS. With an immunoassay-based SIT cutoff for aldosterone of 170 pmol/L, 78 and 162 patients had, respectivel, negative and positive results. All former patients had MS-based measurements of aldosterone < 117 pmol/L, below MS-based cutoffs of 162 pmol/L. Among the 162 patients with pathogenic SIT results, MS returned nonpathologic results in 62, including 32 under 117 pmol/L. Repeat measurements by an independent MS method confirmed nonpathogenic results in 53 patients with discordant results. Patients with discordant results showed a higher (P < 0.0001) prevalence of nonlateralized than lateralized adrenal aldosterone production than patients with concordant results (83% vs 28%). Among patients with nonlateralized aldosterone production, 66% had discordant results. Discordance was more prevalent for the Liaison than iSYS immunoassay (32% vs 16%; P = 0.0065) and was eliminated by plasma purification to remove interferents.

CONCLUSION

These findings raise concerns about the validity of immunoassay-based diagnosis of PA in over 60% of patients with presumed bilateral disease. We provide a simple solution to minimize immunoassay inaccuracy-associated misdiagnosis of PA.

Prevalence of primary aldosteronism in type 2 diabetes mellitus and hypertension: A prospective study from Western India

OBJECTIVE

Type 2 diabetes mellitus (T2DM) and hypertension commonly coexist; however, underlying primary aldosteronism (PA) can lead to worsening of hypertension, glycemia and cardiovascular risk. We aim to screen patients with T2DM and hypertension for PA by conducting a prospective monocentric study from Western India, which included adults with T2DM and hypertension from the outpatient diabetes clinic.

DESIGN

Prospective study.

PATIENTS AND MEASUREMENTS

Patients with an aldosterone renin ratio of ≥1.6 ng/dl/µIU/ml with plasma aldosterone concentration (PAC) ≥ 10 ng/dl were considered to be positive on a screening test. A PAC ≥ 6 ng/dl on seated saline suppression test (SST) was used to confirm the diagnosis of PA.

RESULTS

Four hundred and eighty-six patients were included in this study. Seventy-six (15.6%, 95% confidence interval [CI]: 12.7%-19.1%) patients had a positive screening test with positive confirmatory test in 20 of the 36 (55.5%, 95% CI: 39.3%-71.7%) screen-positive patients who underwent SST. Patients with positive screening test had a higher proportion of females (65.8% vs. 50%; p = .011), frequent history of hypertensive crises (21.1% vs. 8%; p = .001), uncontrolled blood pressure (51.3% vs. 34.6%; p = .006), diagnosis of hypertension before diabetes (32.9% vs. 21.7%; p = .035) and higher systolic (137.6 ± 6.9 vs. 131.2 ± 17.8 mmHg; p = .004) and diastolic (85.3 ± 11.1 vs. 81.7 ± 10.7 mmHg; p = .007) blood pressures. Patients with positive confirmatory test had longer duration of diabetes (108 [60-162] vs. 42 [24-87] months; p = .012), hypertension (84 [42-153] vs. 36 [15-81] months; p = .038) and higher creatinine (1.16 [1.02-1.42] vs. 0.95 [0.84-1.12] mg/dl; p = .021).

CONCLUSIONS

PA is prevalent (at least 4.1%) in Asian Indian patients with T2DM and hypertension. Further studies are needed to assess the cost-effectiveness of routine screening.

Relationship between vascular ageing and left ventricular geometry in patients with newly diagnosed primary aldosteronism

BACKGROUND

Changes in left ventricular (LV) geometry are early manifestations of cardiac damage. The relationship between vascular aging and LV geometry has been reported. However, in newly diagnosed primary aldosteronism (PA), with more severe target organ damage than essential hypertension, the relationship between vascular aging and LV geometry has never been described.

METHODS

We conducted a retrospective study among newly diagnosed PA from 1 January 2017 to 30 September 2021 at the Third Xiangya Hospital. The data of vascular aging parameters were collected, including ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), and carotid intima-media thickness (cIMT). Echocardiography data were collected to assess LV geometry patterns.

RESULTS

A total of 146 patients with newly diagnosed PA were included. The mean age was 44.77 ± 9.79 years, and 46.58% participants were women. Linear regression analysis adjusting all potential confounders showed that cIMT was significantly associated with LV mass index (LVMI) (β=0.164, P=0.028) and baPWV was significantly associated with relative wall thickness (RWT) (β= 0.00005, P=0.025). Multifactorial adjusted logistic regression analysis demonstrated that cIMT was significantly associated with LV hypertrophy (LVH) (OR=7.421, 95%CI: 1.717-815.688, P=0.021) and baPWV was significantly associated with LV concentric geometry (LVCG) (OR=1.003, 95%CI: 1.001-1.006, P=0.017).

CONCLUSION

baPWV was significantly associated with LVCG and cIMT was significantly associated with LVH in newly diagnosed PA. This study provides insights on the importance of baPWV measurement and cIMT measurement in early assessment of cardiac damage in newly diagnosed PA.

Diagnosis and treatment of primary aldosteronism

Primary aldosteronism is a common cause of secondary hypertension associated with excess cardiovascular morbidities. Primary aldosteronism is underdiagnosed because it does not have a specific, easily identifiable feature and clinicians can be poorly aware of the disease. The diagnostic investigation is a multistep process of screening, confirmatory testing, and subtype differentiation of unilateral from bilateral forms for therapeutic management. Adrenal venous sampling is key for reliable subtype identification, but can be bypassed in patients with specific characteristics. For unilateral disease, surgery offers the possibility of cure, with total laparoscopic unilateral adrenalectomy being the treatment of choice. Bilateral forms are treated mainly with mineralocorticoid receptor antagonists. The goals of treatment are to normalise both blood pressure and excessive aldosterone production, and the primary aims are to reduce associated comorbidities, improve quality of life, and reduce mortality. Prompt diagnosis of primary aldosteronism and the use of targeted treatment strategies mitigate aldosterone-specific target organ damage and with appropriate patient management outcomes can be excellent. Advances in molecular histopathology challenge the traditional concept of primary aldosteronism as a binary disease, caused by either a unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia. Somatic mutations drive autonomous aldosterone production in most adenomas. Many of these same mutations have been identified in nodular lesions adjacent to an aldosterone-producing adenoma and in patients with bilateral disease. In addition, germline mutations cause rare familial forms of aldosteronism (familial hyperaldosteronism types 1-4). Genetic testing for inherited forms in suspected cases of familial hyperaldosteronism avoids the burdensome diagnostic investigation in positive patients. In this Review, we discuss advances and future management approaches in the diagnosis of primary aldosteronism.

[Conn's syndrome-Frequent and still too rarely diagnosed to underdiagnosed]

Conn's syndrome represents the most common cause of endocrine hypertension and is associated with an increased cardiovascular risk, a series of comorbidities (including type 2 diabetes mellitus) and with their frequent occurrence. Therefore, a correct and rapid diagnosis is of essential importance. Measurement of the aldosterone-renin ratio is used as a first screening test for primary aldosteronism. This should ideally be evaluated under optimized conditions (e.g. at rest), after adjustment of the blood pressure medication and with an equilibrated potassium balance. In cases of elevated aldosterone to renin ratio, further confirmatory testing as well as imaging of the adrenal glands is needed. After confirmation of Conn's syndrome a differentiation between a unilateral and bilateral adrenal disease is necessary for further treatment planning. The current gold standard is still selective adrenal vein catheterization. Promising alternatives to an adrenal vein catheter, such as functional imaging techniques and measurement of steroid profiles are currently being investigated in clinical trials. In cases of lateralization of aldosterone production, unilateral laparoscopic adrenalectomy of the affected side is the treatment of choice. In contrast, patients with bilateral disease or patients with contraindications for adrenalectomy should receive life-long treatment with mineralocorticoid receptor antagonists.

Primary Hyperaldosteronism: Approach to Diagnosis and Management

Hyperaldosteronism is a relatively more common disorder than previously recognized. Patients with hyperaldosteronism are at high risk for cardiovascular events. Patients suspected of having hyperaldosteronism should undergo initial screening and subsequent confirmatory testing to establish a biochemical diagnosis. Although adrenal computed tomography/magnetic resonance imaging scans often define a disease's subtype, adrenal vein sampling, in order to determine lateralization, may be necessary in some patients who are surgical candidates. Medical therapy using optimal doses of mineralocorticoid receptor antagonists can control symptoms and normalize plasma renin activity. The long-term outcome of patients treated with either surgical or optimal medical therapy appears similar.

Improvement in quality of life and psychological symptoms after treatment for primary aldosteronism: Asian Cohort Study

BACKGROUND

In addition to increased cardiovascular risk, patients with primary aldosteronism (PA) also suffer from impaired health-related quality of life (HRQoL) and psychological symptoms. We assessed for changes in HRQoL and depressive symptoms in a cohort of Asian patients with PA, after surgical and medical therapy.

METHODS

Thirty-four patients with PA were prospectively recruited and completed questionnaires from 2017 to 2020. HRQoL was assessed using RAND-36 and EQ-5D-3L, and depressive symptoms were assessed using Beck Depression Inventory (BDI-II) at baseline, 6 months, and 1 year post-treatment.

RESULTS

At 1 year post-treatment, significant improvement was observed in both physical and mental summative scores of RAND-36, +3.65, P = 0.023, and +3.41, P = 0.033, respectively, as well as four subscale domains (physical functioning, bodily pain, role emotional, and mental health). Significant improvement was also seen in EQ-5D dimension of anxiety/depression at 1 year post-treatment. Patients treated with surgery (n = 21) had significant improvement in EQ-5D index score post-treatment and better EQ-5D outcomes compared to the medical group (n = 13) at 1 year post-treatment. 37.9, 41.6 and 58.6% of patients had symptoms in the cognitive, affective and somatic domains of BDI-II, respectively. There was a significant improvement in the affective domain of BDI-II at 1 year post-treatment.

CONCLUSION

Both surgical and medical therapy improve HRQoL and psychological symptoms in patients with PA, with surgery providing better outcomes. This highlights the importance of early diagnosis, accurate subtyping and appropriate treatment of PA.

Primary aldosteronism is highly prevalent in patients with hypertension and moderate to severe obstructive sleep apnea

STUDY OBJECTIVES

It has been suggested that there might be a pathophysiological link and overlap between primary aldosteronism (PA) and obstructive sleep apnea (OSA). Therefore, in a prospective study, we evaluated the frequency of PA in hypertensive patients suspected of having OSA.

METHODS

We included 207 consecutive hypertensive patients (mean age 53.2 ± 12.1 years, 133 M, 74 F) referred for polysomnography on the basis of one or more of the following clinical features: typical OSA symptoms, resistant or difficult-to-treat hypertension, diabetes, or cardiovascular disease. PA was diagnosed based on thew saline infusion test.

RESULTS

Moderate-to-severe OSA was diagnosed in 94 patients (45.4% of the whole group). PA was diagnosed in 20 patients with OSA (21.3%) compared with 9 patients in the group without OSA (8.0%; P = .006). PA was also frequent in patients in whom symptoms of OSA were a sole indication for PA screening (15.4%) and in patients with and without resistant hypertension (24.5% and 17.8%, respectively). Most patients with PA and OSA were diagnosed with bilateral adrenal hyperplasia (18 patients, 90%). There were no major differences in clinical characteristics between patients with OSA with PA and those without PA. In multivariate models, moderate-to-severe OSA predicted the presence of PA (odds ratio 2.89, P = .018).

CONCLUSIONS

Patients with clinically important moderate-to-severe OSA are characterized by a relatively high frequency of PA. Our results support the recommendations to screen patients with moderate-to-severe OSA for PA, regardless of the presence of other indications for PA screening.

Aldosterone-producing adenoma associated with non-suppressed renin: a case series

Although the aldosterone/renin ratio (ARR) is the preferred screening test for primary aldosteronism (PA), patients with non-suppressed renin and a falsely negative ARR on non-interfering medications have occasionally been reported. This report describes the clinical characteristics and outcomes of seven patients with proven aldosterone-producing adenoma (APA) and non-suppressed renin.Chart review of seven PA patients with an APA and a non-suppressed plasma renin concentration (PRC > 8.4 mU/L) was undertaken to collect data on anthropometric and biochemical characteristics, diagnostic evaluation and postsurgical outcomes.Seven patients (two women and five men) with a proven APA had median (range) PRC, plasma aldosterone and ARR of 20 (9-43) mU/L, 750 (270-1940) pmol/L and 45 (8-62, normal <70), respectively, on non-interfering medications. Six patients had two consecutive ARR measurements and in five of them both were normal. Renal artery stenosis was carefully excluded in all patients. Further evaluation for PA was pursued because of high clinical suspicion (either hypokalaemia and/or a known adrenal mass lesion on imaging). All underwent adrenal vein sampling confirming unilateral PA which was managed by unilateral adrenalectomy. Postsurgical follow-up data either confirmed or were highly suggestive of cure of PA.Strict control of factors known to influence the ARR is crucial to avoid false-negative results. Other causes that could explain a non-suppressed renin should be excluded. In patients with a consistently non-suppressed renin further diagnostic workup for PA should be considered if clinical suspicion remains high.

Seated Saline Suppression Test Is Comparable With Captopril Challenge Test for the Diagnosis of Primary Aldosteronism: A Prospective Study

OBJECTIVE

The saline suppression test (SST) and captopril challenge test (CCT) are commonly used confirmatory tests for primary aldosteronism (PA). Seated SST (SSST) has been reported to be superior to recumbent SST. Whether SSST is better than CCT remains unclear. We aimed to compare the diagnostic accuracy of SSST and CCT in a prospective study.

METHODS

Hypertensive patients at a high risk of PA were consecutively included. Patients with an aldosterone-renin ratio of ≥1.0 ng/dL/μIU/mL were asked to complete SSST, CCT, and the fludrocortisone suppression test (FST). Using FST as a reference standard (plasma aldosterone concentration [PAC] post FST ≥ 6.0 ng/dL), area under the receiver-operating characteristic curve (AUC), sensitivity, and specificity of SSST and CCT were calculated, and multiple regression analyses were performed to identify potential factors leading to false diagnosis.

RESULTS

A total of 196 patients diagnosed with PA and 73 with essential hypertension completed the study. Using PAC post SSST and PAC post CCT to confirm PA, SSST and CCT had comparable AUCs (AUC_SSST 0.87 [95% CI 0.82-0.91] vs AUC_CCT 0.88 [0.83-0.95], P = .646). When PAC post SSST and post CCT were set at 8.5 and 11 ng/dL, respectively, the sensitivity and specificity of SSST (0.72 [0.65, 0.78] and 0.86 [0.76, 0.93]) and CCT (0.73 [0.67, 0.80] and 0.85 [0.75, 0.92]) were not significantly different. In the multiple regression analyses, 1-SD increment of sodium intake resulted in a 40% lower risk of false diagnosis with SSST.

CONCLUSION

SSST and CCT have comparable diagnostic accuracy. Insufficient sodium intake decreases the diagnostic efficiency of SSST but not of CCT. Since CCT is simpler and cheaper, it is preferred over SSST.

[Hyperaldosteronism]

Aldosterone is produced in the adrenal cortex and governs volume and electrolyte homeostasis. Hyperaldosteronism can occur either as primary aldosteronism (renin-independent) or secondary aldosteronism (renin-dependent). As the commonest cause of secondary hypertension, primary aldosteronism is associated with increased cardiovascular risk. Its most prevalent subtypes are aldosterone-producing adenomas as the most frequent unilateral form and bilateral hyperaldosteronism. Unilateral hyperplasia, familial hyperaldosteronism and aldosterone-producing carcinoma are rare. The aldosterone/renin ratio serves as a screening parameter for primary aldosteronism. If this ratio is elevated, confirmatory testing and adrenal imaging are performed. Adrenal venous sampling is considered the gold standard for the distinction of unilateral from bilateral disease. Unilateral disease can potentially be cured by adrenalectomy, whereas patients that are not candidates for surgery or have bilateral disease are treated with mineralocorticoid receptor antagonists. Over the past 10 years, somatic mutations in ion channels or transporters have been identified as causes of aldosterone-producing adenomas and so-called aldosterone-producing cell clusters (potential precursors of adenomas and correlates of bilateral hyperplasia, but also of subclinical hyperaldosteronism). In addition, germline mutations in overlapping genes cause familial hyperaldosteronism. Secondary hyperaldosteronism can occur in patients with hypertension treated with diuretics or in renal artery stenosis.

Minor Change of Plasma Renin Activity during the Saline Infusion Test Provide an Auxiliary Diagnostic Value for Primary Aldosteronism

OBJECTIVE

To clarify whether it has some hidden diagnostic values for PA, especially in the case of an inconclusive SIT result, we investigated the difference in changes of plasma renin activity (PRA) during SIT between patients with PA and non-PA.

METHODS

We measured and compared the SIT parameters of 159 PA patients, 368 non-PA patients, and 43 inconclusive patients who were included in this study.

RESULTS

The PA group showed a minor change of PRA during the SIT (ΔPRA, defined as (pre-SIT PRA-post-SIT PRA)) compared with the non-PA group (0.17 ng/ml/h vs. 1.07 ng/ml/h, P < 0.001). According to ROC analysis, ΔPRA showed a greater AUC than post-SIT PRA (0.897 vs. 0.855, P < 0.001). The cutoff value was 0.5 ng/ml/h, with 90.3% sensitivity and 78.6% specificity. When combined with ARR post-SIT, it showed 81.6% sensitivity and 97.0% specificity for PA diagnosis. Further analysis of 43 patients with an inconclusive SIT result who completed AVS found that ΔPRA was smaller in the confirmed PA group compared with the unconfirmed PA group (0.19 ng/ml/h vs. 0.29 ng/ml/h, P < 0.05); there was no significant difference in PAC post-SIT between two groups. ΔPRA ≤ 0.21 ng/ml/h provides 71.4% sensitivity, 80.0% specificity, and 87.0% PPV for their PA diagnosis.

CONCLUSIONS

PA patients show minor PRA change during SIT; the change of PRA during SIT provides an auxiliary diagnostic value for PA, especially in patients with an inconclusive SIT result.

Role of the Mevalonate Pathway in Adrenocortical Tumorigenesis

3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) is the rate-limiting enzyme of the mevalonate pathway, which generates cholesterol and non-sterol compounds such as isoprenoid, which are involved in key steps of tumorigenesis such as cell growth and proliferation. Our aim was to evaluate the role of the mevalonate pathway in adrenocortical tumors (ACTs). Expression pattern of HMGCR, FDFT1, LDLR, SCARB1, StAR, TSPO, CYP11A1, CYP11B1, CYP17A1, CYP21A1, and HSD3B1 genes, involved in the mevalonate pathway and steroidogenesis, was quantified by real-time RT-PCR in 46 ACT [14 adenomas (ACA) and 11 carcinomas (ACC) from adults and 13 ACA and 8 ACC from pediatric patients]. Effects of the mevalonate pathway inhibition on NCI-H295A cell viability was assessed by colorimetric assay. HMGCR was overexpressed in most adult ACT. The expression of TSPO, STAR, CYP11B1, CYP21A1, and HSD3B1 in adult ACC was significantly lower than in ACA (p<0.05). Regarding pediatric ACT, the expression of genes involved in steroidogenesis was not different between ACA and ACC. Inhibition of isoprenoid production significantly decreased the viability of NCI-H295A cells (p<0.05). However, cholesterol synthesis blockage did not show the same effect on cell viability. Low expression of TSPO ,: StAR, CYP11B1, CYP21A1, and HSD3B1 characterized a signature of adult ACCs. Our data suggest that HMGCR overexpression in adult ACC might lead to intracellular isoprenoid accumulation and cell proliferation. Therefore, the mevalonate pathway is a potential target for ACC treatment.

Significance of Discordant Results Between Confirmatory Tests in Diagnosis of Primary Aldosteronism

CONTEXT

Current clinical guidelines recommend confirmation of a positive result in at least one confirmatory test in the diagnosis of primary aldosteronism (PA). Clinical implication of multiple confirmatory tests has not been established, especially when patients show discordant results.

OBJECTIVE

The aim of the present study was to explore the role of 2 confirmatory tests in subtype diagnosis of PA.

DESIGN AND SETTING

A retrospective cross-sectional study was conducted at two referral centers.

PARTICIPANTS AND METHODS

We identified 360 hypertensive patients who underwent both a captopril challenge test (CCT) and a saline infusion test (SIT) and exhibited at least one positive result. Among them, we studied 193 patients with PA whose data were available for subtype diagnosis based on adrenal vein sampling (AVS).

MAIN OUTCOME MEASURE

The prevalence of bilateral subtype on AVS according to the results of the confirmatory tests was measured.

RESULTS

Of patients studied, 127 were positive for both CCT and SIT (double-positive), whereas 66 were positive for either CCT or SIT (single-positive) (n = 34 and n = 32, respectively). Altogether, 135 were diagnosed with bilateral subtype on AVS. The single-positive patients had milder clinical features of PA than the double-positive patients. The prevalence of bilateral subtype on AVS was significantly higher in the single-positive patients than in the double-positive patients. (63/66 [95.5%] vs 72/127 [56.7%], P < .01). Several clinical parameters were different between CCT single-positive and SIT single-positive patients.

CONCLUSION

Patients with discordant results between CCT and SIT have a high probability of bilateral subtype of PA on AVS.

Aldosterone is Aberrantly Regulated by Various Stimuli in a High Proportion of Patients with Primary Aldosteronism

CONTEXT

In primary aldosteronism (PA), aldosterone secretion is relatively independent of the renin-angiotensin system, but can be regulated by several other stimuli.

OBJECTIVE

To evaluate aldosterone response to several stimuli in a series of patients with PA secondary either to bilateral adrenal hyperplasia (BAH) or unilateral aldosterone-producing adenoma (APA).

DESIGN AND SETTING

Prospective cohort study conducted in a university teaching hospital research center.

PATIENTS

Forty-three patients with confirmed PA and subtyped by adrenal vein sampling (n = 39) were studied, including 11 with BAH, 28 with APA, and 4 with undefined etiology. We also studied 4 other patients with aldosterone and cortisol cosecretion.

INTERVENTIONS

We systematically explored aberrant regulation of aldosterone using an in vivo protocol that included the following stimulation tests performed over 3 days under dexamethasone suppression: upright posture, mixed meal, adrenocorticotropin (ACTH) 1-24, gonadotropin-releasing hormone (GnRH), vasopressin, and serotonin R4 agonist.

MAIN OUTCOME MEASURES

Positive response was defined as >50% renin or ACTH-independent increase in plasma aldosterone/cortisol concentration following the various stimulation tests.

RESULTS

Renin-independent aldosterone secretion increased in response to several aberrant stimuli (upright posture, GnRH) in up to 83% of patients with APA or BAH in whom ACTH 1-24 and HT4R agonists also produced aldosterone oversecretion in all patients. The mean significant aberrant responses per patient was similar in BAH (4.6) and in APA (4.0).

CONCLUSIONS

Aldosterone secretion in PA is relatively autonomous from the renin-angiotensin system, but is highly regulated by several other stimuli, which contributes to the large variability of aldosterone levels in PA patients.

The Value of Different Single or Combined Indexes of the Captopril Challenge Test in the Diagnosis of Primary Aldosteronism

OBJECTIVE

The result interpretation of the captopril challenge test (CCT) for the diagnosis of primary aldosteronism (PA) is not standardized. Superiorities of different indexes in the CCT have not been fully investigated. We aimed to comprehensively evaluate the value and influence factors of different CCT-associated indexes in the diagnosis of PA.

METHODS

We enrolled 312, 85, 179 and 97 patients in the groups of PA, essential hypertension (EH), unilateral PA (UPA) and bilateral PA (BPA), respectively. For each single index investigated, we computed diagnostic estimates including the area under the receiver operating characteristic curve (AUC). We performed pre-specified subgroup analyses to explore influence factors. We assessed the diagnostic value of combined indexes in binary logistic regression models.

RESULTS

Post-CCT aldosterone to renin ratio (ARR) (AUC = 0.8771) and plasma aldosterone concentration (PAC) (AUC = 0.8769) showed high value in distinguishing PA from EH, and their combination (AUC = 0.937) was even superior to either alone. The diagnostic efficacy was moderately high for post-CCT aldosterone to angiotensin II ratio (AA2R) (AUC = 0.834) or plasma renin activity (PRA) (AUC = 0.795) but low for the suppression percentage of PAC (AUC = 0.679). Post-CCT PAC had a significantly higher AUC in the UPA than BPA subgroup (AUC = 0.914 vs 0.827, P<0.05).

CONCLUSION

We can take post-CCT ARR and PAC altogether into account to distinguish PA from EH, while caution should be taken to interpret CCT results with the suppression percentage of PAC. Post-CCT PAC may perform better to identify the unilateral than bilateral form of PA.

Confounders of the aldosterone-to-renin ratio when used as a screening test in hypertensive patients: A critical analysis of the literature

The aldosterone‐to‐renin ratio (ARR) is a common screening test for primary aldosteronism in hypertensives. However, there are many factors which could confound the ARR test result and reduce the accuracy of this test. The present review's objective is to identify these factors and to describe to what extent they affect the ARR. Our analysis revealed that sex, age, posture, and sodium‐intake influence the ARR, whereas assay techniques do not. Race and body mass index have an uncertain effect on the ARR. We conclude that several factors can affect the ARR. Not taking these factors into account could lead to misinterpretation of the ARR.

Comparison of the shortened and standard saline infusion tests for primary aldosteronism diagnostics

The saline infusion test (SIT) is widely used to confirm PA, but some patients may not tolerate the standard loading volume of 2 L saline over 4 h. The shortened SIT, loading only 1 L saline over 2 h, is suggested to be useful and would be more acceptable if the diagnostic utility of the shortened SIT is comparable to that of the standard SIT. We compared the diagnostic values of the plasma aldosterone concentration after 2 h of 1 L saline loading (2 h PAC) and that after 4 h of 2 L saline loading (4 h PAC) for the prediction of unilateral aldosterone hypersecretion and postoperative outcome. This retrospective, single-center study involved 555 PA-suspected patients who underwent SIT, 153 patients with adrenal vein sampling (AVS) results, and 37 patients with a 1-year postoperative evaluation. To detect the Japanese cutoff of 4 h PAC > 60 pg/mL, a 2-h PAC Youden Index at 66 pg/mL showed 91% sensitivity and 75% specificity. For unilateral aldosterone hypersecretion, the sensitivity and specificity of 2 h PAC were not inferior to those of 4 h PAC by Markov chain Monte Carlo (MCMC) methods. The sensitivity and specificity of 2 h PAC for postoperative reduction of anti-hypertensive drugs were also not inferior to those of 4 h PAC. Although using the 2 h PAC > 66 pg/mL cutoff may increase false positives for PA diagnosis, the shortened SIT, possibly using a cutoff value higher than 66 pg/mL, may be as useful as the standard SIT for selecting PA patients for AVS and to predict postoperative outcomes with reduced burden on patients.

Genetics, prevalence, screening and confirmation of primary aldosteronism: a position statement and consensus of the Working Group on Endocrine Hypertension of The European Society of Hypertension

: Autonomous aldosterone overproduction represents the underlying condition of 5-10% of patients with arterial hypertension and carries a significant burden of mortality and morbidity. The diagnostic algorithm for primary aldosteronism is sequentially based on hormonal tests (screening and confirmation tests), followed by lateralization studies (adrenal CT scanning and adrenal venous sampling) to distinguish between unilateral and bilateral disease. Despite the recommendations of the Endocrine Society guideline, primary aldosteronism is largely underdiagnosed and undertreated with high between-centre heterogeneity. Experts from the European Society of Hypertension have critically reviewed the available literature and prepared a consensus document constituting two articles to summarize current knowledge on the epidemiology, diagnosis, treatment, and complications of primary aldosteronism.

Reassessment of Urinary Aldosterone Measurement After Saline Infusion in Primary Aldosteronism

Context

Urinary aldosterone levels (Uald) are widely measured in the oral sodium-loading test to confirm primary aldosteronism (PA), but reliable studies on their diagnostic value are limited. This may be due to the difficulty in collecting urine with reliable accuracy, keeping oral sodium intake constant between patients. Therefore, we focused on 24-hour Uald after intravenous saline infusion in a hospitalized setting, which provides a reliable sodium load in consistent amounts.

Objective

Comparing plasma aldosterone concentrations (PAC) and Uald after saline infusion in the sitting position, to evaluate the accuracy in determining PA subtypes and the correlation of both measurements.

Design and Setting

This was a retrospective cross-sectional study in a single referral center.

Patients

Of 53 patients without renal dysfunction who were diagnosed with PA and underwent adrenal venous sampling, 16 and 37 were diagnosed with unilateral and bilateral PA, respectively.

Main Outcome Measures

Uald collected for 24 hours and PAC after saline infusion.

Results

The area under the receiver operating characteristic curve for diagnosing unilateral PA was not significantly different between Uald and PAC after saline infusion (0.921 and 0.958, respectively; P = 0.370). The predicted optimal cutoff value of Uald was 16.5 μg/day (sensitivity, 87.5%; specificity, 100%), and that of PAC after saline infusion was 19.3 ng/dL (sensitivity, 87.5%; specificity, 97.3%). In studied patients with PA, Uald was positively correlated with PAC after saline infusion (r = 0.617; P < 0.001).

Conclusions

We reassessed Uald in PA patients under sufficient sodium loading and demonstrated the correlation between Uald and PAC after saline infusion.

Primary Aldosteronism: Where Are We Now? Where to from Here?

The past nine years have seen major advances in establishing the etiology of unilateral primary aldosteronism, and very possibly that of bilateral hyperaldosteronism, in response to somatic mutations in aldosterone synthase expressing cells. Though there have been important advances in the management of primary aldosteronism, in small but convincing studies, they represent minor changes to current guidelines. What has been totally absent is consideration of the public health issue that primary aldosterone represents, and the public policy issues that would be involved in addressing the disorder. In his introduction to PiPA 6, Martin Reincke calculated that only one in a thousand patients in Germany with primary aldosteronism were treated appropriately, an astounding figure for any disease in the 21st century. Towards remedying this totally unacceptable public health issue, the author proposes a radical simplification and streamlining of screening for primary aldosteronism, and the management of most patients by general practitioners. The second bottle-neck in current management is that of mandatory adrenal venous sampling for all but 1-2% of patients, a costly procedure requiring rare expertise. Ideally, it should be reserved - on the basis of likelihood, enhanced imaging, or peripheral steroid profiles - for a small minority of patients with clear evidence for unilateral disease. Only when costs are minimized and roadblocks removed will primary aldosteronism be properly treated as the public health issue that it is.

Baseline Plasma Aldosterone Level and Renin Activity Allowing Omission of Confirmatory Testing in Primary Aldosteronism

CONTEXT

Previous studies have proposed cutoff value of baseline plasma aldosterone concentration (bPAC) under renin suppression that could diagnose primary aldosteronism (PA) without confirmatory testing. However, those studies are limited by selection bias due to a small number of patients and a single-center study design.

OBJECTIVE

This study aimed to determine cutoff value of bPAC and baseline plasma renin activity (bPRA) for predicting positive results in confirmatory tests for PA.

DESIGN

The multi-institutional, retrospective, cohort study was conducted using the PA registry in Japan (JPAS/JRAS). We compared bPAC in patients with PA who showed positive and negative captopril challenge test (CCT) or saline infusion test (SIT) results.

PATIENTS

Patients with PA who underwent CCT (n = 2256) and/or SIT (n = 1184) were studied.

MAIN OUTCOME MEASURES

The main outcomes were cutoff value of bPAC (ng/dL) and bPRA (ng/mL/h) for predicting positive CCT and/or SIT results.

RESULTS

In patients with renin suppression (bPRA ≤ 0.3), the cutoff value of bPAC that would give 100% specificity for predicting a positive SIT result was lower than that for predicting a positive CCT result (30.85 vs 56.35, respectively). Specificities of bPAC cutoff values ≥ 30.85 for predicting positive SIT and CCT results remained high (100.0% and 97.0%, respectively) in patients with bPRA ≤ 0.6. However, the specificities of bPAC cutoff values ≥ 30.85 for predicting positive SIT and CCT results decreased when patients with bPRA > 0.6 were included.

CONCLUSION

Confirmatory testing could be omitted in patients with bPAC ≥ 30.85 in the presence of bPRA ≤ 0.6.

Mass spectrometry reveals misdiagnosis of primary aldosteronism with scheduling for adrenalectomy due to immunoassay interference

BACKGROUND

Diagnosis of primary aldosteronism (PA) involves a multistep process reliant on the accuracy of aldosterone measurements at each step. We report on immunoassay interference leading to a wrongful diagnosis and indication for surgical intervention.

CASE

A 38-year old hypertensive male with a 1.4 cm left adrenal mass was diagnosed with PA based on an elevated aldosterone:renin ratio and a positive saline infusion test. Adrenal venous sampling (AVS) indicated left-sided aldosterone hypersecretion, supporting a decision to remove the left adrenal. The patient was also enrolled in a study to evaluate mass spectrometry-based steroid profiling, which indicated plasma aldosterone concentrations measured in five different peripheral samples averaging only 11% those of the immunoassay. Mass spectrometric measurements did not support left-sided adrenal aldosterone hypersecretion. Two independent laboratories confirmed differences in measurements by immunoassay and mass spectrometry. Lowered concentrations measured by the immunoassay that matched those by mass spectrometry were achieved after sample purification to remove macromolecules, confirming immunoassay interference.

CONCLUSIONS

Although our patient may represent an isolated case of immunoassay interference leading to misdiagnosis of PA, unnecessary AVS and potentially wrongful removal of an adrenal, it is also possible that such inaccuracies may impact the diagnostic process and treatment for other patients.

Primary aldosteronism: Treatment of the disease, and new therapeutic approaches

Primary aldosteronism is currently considered to represent 5-13% of hypertension, yet fewer than 1% of patients with the disorder are ever diagnosed and treated. Current management of patients screened and confirmed positive for primary aldosteronism involves imaging, and with very few exceptions adrenal venous sampling to lateralize (or not) hyperaldosteronism. Unilateral disease is treated by adrenalectomy: bilateral disease by mineralocorticoid receptor antagonists and conventional antihypertensives as/if required. New therapeutic approaches include (i) routine screening on first presentation for hypertension; (ii) harmonisation of cut-offs for renin and aldosterone, plus use of 24-h urinary rather than spot plasma values for the latter; (iii) adoption of a dexamethasone enhanced seated saline suppression test for confirmation exclusion; (iv) enhanced imaging and steroid profiles as partial replacement for adrenal venous sampling; and finally (v), inclusion of low dose spironolactone in first-line therapy for hypertension.

A clinical prediction score using age at diagnosis and saline infusion test parameters can predict aldosterone-producing adenoma from idiopathic adrenal hyperplasia

PURPOSE

Accurate subtyping of the primary aldosteronism into aldosterone-producing adenoma (APA) and idiopathic adrenal hyperplasia (IAH) is important to direct for specific treatment modalities. The objective of the study was to compare the clinical and biochemical parameters of APA and IAH patients to derive a Clinical Prediction Score reliably predicting APA from IAH.

METHODS

This was a retrospective multi-centre study recruiting 38 APA patients and 42 IAH patients from four major hospitals in Hong Kong using database from Surgical Outcomes Monitoring and Improvement Programme and Clinical Data Analysis and Reporting System. Their clinical and biochemical parameters were evaluated.

RESULTS

Patients in APA group were younger than IAH group (mean age 48.6 ± 9.2 vs. 57.1 ± 7.3 years old, p < 0.001), had more suppressed renin before saline infusion in saline infusion test (SIT) (median 0.19 [IQR 0.15-0.37] vs. 0.39 [IQR 0.19-0.69] ng/mL/h, p = 0.01), and higher aldosterone level after saline infusion in SIT (median 674 [IQR 498-1000] vs. 327 [IQR 242-483] pmol/L, p < 0.001). A clinical prediction score using three parameters was devised, comprising age at diagnosis < 50 years, PRA before saline infusion in SIT ≤ 0.26 ng/mL/h, and aldosterone level after saline infusion in SIT ≥ 424 pmol/L. A score of 2 would predict APA with a sensitivity of 84.2% and specificity of 88.1%, and a score of 3 would predict APA with a sensitivity of 31.6% and specificity of 100%.

CONCLUSIONS

Clinical Prediction Score based on the combination of age at diagnosis, PRA, and aldosterone level in the saline infusion tests could reliably predict APA from IAH.

Prevalence, diagnosis and outcomes of treatment for primary aldosteronism

Primary aldosteronism (PA) is the most common potentially curable form of hypertension. The overproduction of aldosterone leads to an increased risk of cardiovascular and cerebrovascular events as well as adverse effects to the heart and kidney and psychological disorders. PA is mainly caused by unilateral aldosterone excess due to an aldosterone-producing adenoma or bilateral excess due to bilateral adrenocortical hyperplasia. The diagnostic work-up of PA comprises three steps: screening, confirmatory testing and differentiation of unilateral surgically-correctable forms from medically treated bilateral PA. These specific treatments can mitigate or reverse the increased risks associated with PA. Herein we summarise the prevalence, outcomes and current and future clinical approaches for the diagnosis of primary aldosteronism.

Diagnosis of Primary Aldosteronism by Seated Saline Suppression Test-Variability Between Immunoassay and HPLC-MS/MS

BACKGROUND

In primary aldosteronism (PA), excessive, autonomous secretion of aldosterone is not suppressed by salt loading or fludrocortisone. For seated saline suppression testing (SSST), the recommended diagnostic cutoff 4-hour plasma aldosterone concentration (PAC) measured by high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS is 162 pmol/L. Most diagnostic laboratories, however, use immunoassays to measure PAC. The cutoff for SSST using immunoassay is not known. We hypothesized that the cutoff is different between the assays.

METHODS

We analyzed 80 of the 87 SSST tests that were performed during our recent study defining the HPLC-MS/MS cutoff. PA was confirmed in 65 by positive fludrocortisone suppression testing (FST) and/or lateralization on adrenal venous sampling and excluded in 15 by negative FST. PAC was measured by a chemiluminescence immunoassay (PACIA) in the SSST samples using the DiaSorin Liaison XL analyzer, and receiver operating characteristics (ROC) analysis was performed to identify the PACIA cutoff.

RESULTS

ROC revealed good performance (area under the curve = 0.893; P < .001) of 4-hour postsaline PACIA for diagnosis of PA and an optimal diagnostic cutoff of 171 pmol/L, with sensitivity and specificity of 95.4% and 80.0%, respectively. A higher cutoff of 217 pmol/L improved specificity (86.7%) with lower sensitivity (86.2%). PACIA measurements strongly correlated with PAC measured by HPLC-MS (r = 0.94, P < .001).

CONCLUSIONS

A higher diagnostic cutoff for SSST should be employed when PAC is measured by immunoassay rather than HPLC-MS/MS. The results suggest that (i) PA can be excluded if 4-hour PACIA is less than 171 pmol/L, and (ii) PA is highly likely if the PACIA is greater than 217 pmol/L by chemiluminescence immunoassay. A gray zone exists between the cutoffs of 171 and 217 pmol/L, likely reflecting a lower specificity of immunoassay.