Screening for primary aldosteronism in hypertensive subjects: results from two German epidemiological studies

Unawareness of Primary Aldosteronism as a Common Cause of Hypokalemia - Insights from the IPAHK+ Trial (Incidence of Primary Aldosteronism in Patients with Hypokalemia)

Hypokalemia plays an important role in the diagnosis and management of primary aldosteronism (PA). While the hypokalemic variant of the disease accounts for about one third of all cases, little is known about the incidence of PA in hypokalemic populations. The IPAHK+ study is an epidemiological, cross-sectional trial to provide evidence on the incidence of PA in hypokalemic patients from a university hospital outpatient population. Recruitment of outpatients with hypokalemia≤3 mmol/l is carried out on a continuous referral-basis through an automated data delivery system. Up to an interim data closure, 66 patients underwent the study protocol. The mean age of the participants was 52.9±1.5 years with an equal sex ratio of 1:1 women to men, a mean potassium value of 2.78±0.31 mmol/l [1.8;3.0] and a prevalence of arterial hypertension of 72.7%. PA was diagnosed in 46.6% of all participants, all of whom had a history of hypertension. Incidence of PA increased continuously with decreasing potassium levels with proportions of 26.7%, 50% and 57.1% in the subgroups of 3.0 mmol/l (n=15), 2.8-2.9 mmol/l (n=22) and≤2.7 mmol/l (n=21), respectively. Prior to testing, 59.1% of all patients presented at least with one plausible other cause of hypokalemia. The incidence of PA in the investigated outpatient population was more than 4 out of 10 and inversely correlated with baseline potassium levels. Moderate or severe hypokalemia, regardless of its cause, should therefore prompt evaluation for PA in hypertensive individuals. Normotensive hypokalemic PA was not observed in this cohort.

Urine steroid metabolomics as a diagnostic tool in primary aldosteronism

Primary aldosteronism (PA) causes 5-10% of hypertension cases, but only a minority of patients are currently diagnosed and treated because of a complex, stepwise, and partly invasive workup. We tested the performance of urine steroid metabolomics, the computational analysis of 24-hour urine steroid metabolome data by machine learning, for the identification and subtyping of PA. Mass spectrometry-based multi-steroid profiling was used to quantify the excretion of 34 steroid metabolites in 24-hour urine samples from 158 adults with PA (88 with unilateral PA [UPA] due to aldosterone-producing adenomas [APAs]; 70 with bilateral PA [BPA]) and 65 sex- and age-matched healthy controls. All APAs were resected and underwent targeted gene sequencing to detect somatic mutations associated with UPA. Patients with PA had increased urinary metabolite excretion of mineralocorticoids, glucocorticoids, and glucocorticoid precursors. Urine steroid metabolomics identified patients with PA with high accuracy, both when applied to all 34 or only the three most discriminative steroid metabolites (average areas under the receiver-operating characteristics curve [AUCs-ROC] 0.95-0.97). Whilst machine learning was suboptimal in differentiating UPA from BPA (average AUCs-ROC 0.65-0.73), it readily identified APA cases harbouring somatic KCNJ5 mutations (average AUCs-ROC 0.79-85). These patients showed a distinctly increased urine excretion of the hybrid steroid 18-hydroxycortisol and its metabolite 18-oxo-tetrahydrocortisol, the latter identified by machine learning as by far the most discriminative steroid. In conclusion, urine steroid metabolomics is a non-invasive candidate test for the accurate identification of PA cases and KCNJ5-mutated APAs.

Key to the Treatment of Primary Aldosteronism in Secondary Hypertension: Subtype Diagnosis

PURPOSE OF REVIEW

Primary aldosteronism (PA) is a leading global cause of secondary hypertension. Subtyping diagnosis of PA is the key to surgery, but accurate classification of PA is crucial but challenging in clinical diagnosis and treatment. The purpose of this review is to provide a summary of current literature and propose subtyping diagnosis flow chart to help us classify PA quickly and accurately.

RECENT FINDINGS

Early diagnosis and accurate typing are essential for the timely treatment and appropriate management of PA. For most patients, adrenal venous sampling (AVS) is the central choice for typing diagnosis, but AVS is invasive and difficult to promote effectively. CT can help identify unilateral typical adenomas in select patients to avoid AVS. New radionuclide imaging has shown value in the diagnosis and classification of PA, which distinguishes adrenocortical hyperplasia from adenoma and can replace AVS in some patients. Accurately diagnosing unilateral PA is crucial for determining the appropriate treatment strategy for PA. The simple flow chart of PA subtyping diagnosis based on the current literature needs to be verified and evaluated by follow-up researches.

Laparoscopic adrenalectomy for adrenal tumors with endocrine activity: Perioperative management pathways for reduced complications and improved outcomes

The major adrenal tumors with endocrine activity are primary aldosteronism, Cushing's syndrome/mild autonomous cortisol secretion, and pheochromocytoma/paraganglioma. Excessive aldosterone secretion in primary aldosteronism causes cardiovascular, renal, and other organ damage in addition to hypertension and hypokalemia. Cortisol hypersecretion in Cushing's syndrome/mild autonomous cortisol secretion causes obesity, hypertension, impaired glucose tolerance, and cardiometabolic syndrome. Massive secretion of catecholamines in pheochromocytoma/paraganglioma causes hypertension and cerebrocardiovascular disease due to rapid blood pressure fluctuation. Moreover, pheochromocytoma multi-system crisis is a feared and possibly fatal presentation of pheochromocytoma/paraganglioma. Thus, adrenal tumors with endocrine activity are considered an indication for adrenalectomy, and perioperative management is very important. They have a risk of perioperative complications, either due to direct hemodynamic effects of the hormone hypersecretion or due to hormone-related comorbidities. In the last decades, deliberate preoperative evaluation and advanced perioperative management have significantly reduced complications and improved outcomes. Furthermore, improvements in anesthesia and surgical techniques with the feasibility of laparoscopic adrenalectomy have contributed to reduced morbidity and mortality. However, there are still several challenges to be considered in the perioperative care of these patients. There are very few data available prospectively to guide clinical management, due to the rarity of adrenal tumors with endocrine activity. Therefore, most guidelines are based on retrospective data analyses or small case series. In this review, the latest knowledge is summarized, and practical pathways to reduce perioperative complications and improve outcomes in adrenal tumors with endocrine activity are presented.

Prevalence of High Aldosterone-Renin Ratio in Patients With Hypertension in Basrah

BACKGROUND AND AIM

Aldosterone-renin ratio (ARR) is an important screening tool for the assessment of primary aldosteronism as a cause of secondary hypertension. This study aimed to measure the prevalence of patients with elevated ARR among samples of Iraqi patients with hypertension.

METHODS

A retrospective study was conducted at Faiha Specialized Diabetes, Endocrine and Metabolism Center (FDEMC) in Basrah during the period of February 2020 to November 2021. We evaluated the records of patients with hypertension whom were screened for endocrine cause, and an ARR cut-off equal or more than 5.7 was considered elevated.

RESULTS

Of the total 150 patients enrolled, 39 (26%) of them had an elevated ARR. No statistically significant association for the elevated ARR with age, gender, BMI, duration of hypertension, systolic and diastolic blood pressure, pulse rate, and presence or absence of diabetes mellitus or lipid profile.

CONCLUSION

High frequency of elevated ARR was seen in 26% of patients with hypertension. More studies need to be conducted in the future taking larger samples.

Assessment of skin microcirculation in primary aldosteronism: impaired microvascular responses compared to essential hypertensives and normotensives

Primary aldosteronism (PA) is associated with considerably higher cardiovascular risk and increased prevalence of organ damage compared to essential hypertension (EH). Laser speckle contrast imaging (LSCI) has emerged as a novel non-invasive tool to assess of skin microcirculation. Our aim was to evaluate skin microvascular function (SMF) using LSCI coupled with post-occlusive reactive hyperemia (PORH) in a group of PA patients (PAs) compared to patients with EH (EHs) and normotensive controls (NTs). We enrolled PAs, age- and gender-matched with EHs and NTs. All participants underwent SMF assessment by LSCI with PORH. We enrolled 109 participants including 29 PAs, 47 EHs, and 33 NTs. SMF was significantly impaired in PAs, including peak time (p < 0.001) and base to peak flux (p < 0.001) compared to NTs and EHs. Among PAs, plasma aldosterone showed a positive correlation with occlusion flux (p = 0.005). Our study shows for the first time that PAs present impaired SMF as assessed with LSCI coupled with PORH, not only compared to NTs but also compared to EHs with similar blood pressure profile. Further studies are needed to investigate the clinical impact of such alterations in terms of pathophysiology and cardiovascular risk prediction.

Who should be screened for primary aldosteronism? A comprehensive review of current evidence

Arterial hypertension is a major risk factor for cardiovascular disease. The prevalence of primary aldosteronism (PA) ranges from 5% to 10% in the general hypertensive population and is regarded as one of the most common causes of secondary hypertension. There are two major causes of PA: bilateral adrenal hyperplasia and aldosterone-producing adenoma. The diagnosis of PA comprises screening, confirmatory testing, and subtype differentiation. The Endocrine Society Practice Guidelines for the diagnosis and treatment of PA recommends screening of patients at an increased risk of PA. These categories include patients with stage 2 and 3 hypertension, drug-resistant hypertension, hypertensive with spontaneous or diuretic-induced hypokalemia, hypertension with adrenal incidentaloma, hypertensive with a family history of early onset hypertension or cerebrovascular accident at a young age, and all hypertensive first-degree relatives of patients with PA. Recently, several studies have linked PA with obstructive sleep apnea and atrial fibrillation unexplained by structural heart defects and/or other conditions known to cause the arrhythmia, which may be partly responsible for the higher rates of cardiovascular and cerebrovascular accidents in patients with PA. The aim of this review is to discuss which patients should be screened for PA, focusing not only on well-established guidelines but also on additional groups of patients with a potentially higher prevalence of PA, as has been reported in recent research.

The metabolic phenotype of patients with primary aldosteronism: impact of subtype and sex - a multicenter-study of 3566 Caucasian and Asian subjects

BACKGROUND

Accumulating evidence suggests that primary aldosteronism (PA) is associated with several features of the metabolic syndrome, in particular with obesity, type 2 diabetes mellitus, and dyslipidemia. Whether these manifestations are primarily linked to aldosterone-producing adenoma (APA) or bilateral idiopathic hyperaldosteronism (IHA) remains unclear. The aim of the present study was to investigate differences in metabolic parameters between APA and IHA patients and to assess the impact of treatment on these clinical characteristics.

METHODS

We conducted a retrospective multicenter study including 3566 patients with APA or IHA of Caucasian and Asian origin. We compared the prevalence of metabolic disorders between APA and IHA patients at the time of diagnosis and 1-year post-intervention, with special references to sex differences. Furthermore, correlations between metabolic parameters and plasma aldosterone, renin, or plasma cortisol levels after 1 mg dexamethasone (DST) were performed.

RESULTS

As expected, APA patients were characterized by higher plasma aldosterone and lower serum potassium levels. Only female IHA patients demonstrated significantly worse metabolic parameters than age-matched female APA patients, which were associated with lower cortisol levels upon DST. One-year post-intervention, female adrenalectomized patients showed deterioration of their lipid profile, when compared to patients treated with mineralocorticoid receptor antagonists. Plasma aldosterone levels negatively correlated with the BMI only in APA patients.

CONCLUSIONS

Metabolic alterations appear more prominent in women with IHA. Although IHA patients have worse metabolic profiles, a correlation with cortisol autonomy is documented only in APAs, suggesting an uncoupling of cortisol action from metabolic traits in IHA patients.

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.

Incidence of Primary Aldosteronism in Patients with Hypokalemia (IPAHK+): Study Design and Baseline Characteristics

Hypokalemia plays a central role for case finding, course, treatment decision, and prognosis of patients with primary aldosteronism. However, to date there is a lack of high-level evidence about the incidence of primary aldosteronism in hypokalemic patients. The IPAHK⁺study is an epidemiological, cross-sectional, monocentric study to provide evidence on the incidence of PA in a hypokalemic population. The aim of the current analysis was to describe the baseline characteristics of the first 100 patients eligible for study inclusion. The recruitment of patients with hypokalemia (≤3 mmol/l) is carried out continuously on a referral-basis by the central laboratory of the University Hospital Zurich through an automated suitability testing and data delivery system. The careful evaluation of the first 100 reported patients was based on the available reporting system. Out of 28 140 screened patients, 222 (0.79%) were identified with a serum potassium value of≤3 mmol/l (mean 2.89±0.02 mmol/l). Mean potassium levels were slightly lower in non-hypertensive subjects compared to hypertensive subjects (mean difference 0.07 mmol/l, p=0.033), while no significant difference was found between the sexes and patients with and without the diagnosis of primary aldosteronism, atrial fibrillation, or the use of diuretics. The incidence of PA was 4% in the total population studied and 7.5% in the subgroup of hypertensive patients. In conclusion, the continuous enrollment of patients from the IPHAK⁺hypokalemia registry into the IPAHK⁺trial will provide evidence about the actual incidence of primary aldosteronism in a hypokalemic outpatient population.

Developing a research database of primary aldosteronism: rationale and baseline characteristics

BACKGROUND

Management of primary aldosteronism (PA) has become a research hotspot in the field of endocrinology. To obtain reliable research evidence, it is necessary to establish a high-quality PA research database.

METHODS

The establishment of PA research database involved two steps. Firstly, patients with confirmation of PA diagnosis between 1 Jan 2009 to 31 Aug 2019 at West China Hospital were identified and data were extracted. Secondly, patients with confirmatory testing for PA will be enrolled into a prospective cohort. Data will be prospectively collected based on the case report forms since 1 Sep 2019. We evaluated the quality of research database through assessment of quality of key variables.

RESULTS

Totally, 862 patients diagnosed as PA were identified, of which 507 patients who had positive confirmatory testing for PA were included into the retrospective database. Among 862 patients diagnosed as PA, the mean systolic blood pressure (SBP) was 156.1 (21.7) mmHg, mean diastolic blood pressure (DBP) was 97.2 (14.5) mmHg. Among included patients, the mean serum potassium level was 2.85 (IQR, (2.47-3.36) mmol/L, and the mean plasma aldosterone concentration (PAC) was 28.1 (IQR, 20.0-40.4) ng/dL. The characteristics of patients with positive confirmatory testing for PA were similar. Validation of data extracting and linking showed the accuracy were 100%. Evaluation of missing data showed that the completeness of BMI (95.9%), SBP (99.4%) and DBP (99.4%) were high.

CONCLUSION

Through integrating retrospective and prospective cohort of PA, a research database of PA with high quality and comprehensive data can be established. We anticipate that the research database will provide a high level of feasibility for management of PA in China.

Therapeutic Outcomes with Surgical and Medical Management of Primary Aldosteronism

PURPOSE OF REVIEW

Primary aldosteronism (PA) is the most common cause of secondary hypertension and is significantly under-diagnosed. Delays in diagnosis and treatment can lead to cardiovascular morbidity and mortality. The goal of this study is to review the management of PA, with a focus on medical and surgical treatment outcomes.

RECENT FINDINGS

PA causes cardiovascular dysfunction in excess of degree of hypertension. Adrenalectomy demonstrates a therapeutic advantage over mineralocorticoid antagonist (MRA) therapy, after controlling for degree of hypertension and subtype of PA. Higher rates of atrial fibrillation, heart failure, stroke, and incidence of chronic kidney disease are observed in subjects treated with MRAs than in subjects treated with adrenalectomy. The therapeutic benefit of surgery may reflect definitive resolution of excess aldosterone. Complete mineralocorticoid blockade may achieve similar benefit to adrenalectomy. Adrenalectomy is the most effective treatment for unilateral PA. Biomarkers for MRA therapy might inform optimal medical therapy of bilateral adrenal hyperplasia.

Testing for Primary Aldosteronism and Mineralocorticoid Receptor Antagonist Use Among U.S. Veterans : A Retrospective Cohort Study

BACKGROUND

Primary aldosteronism is a common cause of treatment-resistant hypertension. However, evidence from local health systems suggests low rates of testing for primary aldosteronism.

OBJECTIVE

To evaluate testing rates for primary aldosteronism and evidence-based hypertension management in patients with treatment-resistant hypertension.

DESIGN

Retrospective cohort study.

SETTING

U.S. Veterans Health Administration.

PARTICIPANTS

Veterans with apparent treatment-resistant hypertension (n = 269 010) from 2000 to 2017, defined as either 2 blood pressures (BPs) of at least 140 mm Hg (systolic) or 90 mm Hg (diastolic) at least 1 month apart during use of 3 antihypertensive agents (including a diuretic), or hypertension requiring 4 antihypertensive classes.

MEASUREMENTS

Rates of primary aldosteronism testing (plasma aldosterone-renin) and the association of testing with evidence-based treatment using a mineralocorticoid receptor antagonist (MRA) and with longitudinal systolic BP.

RESULTS

4277 (1.6%) patients who were tested for primary aldosteronism were identified. An index visit with a nephrologist (hazard ratio [HR], 2.05 [95% CI, 1.66 to 2.52]) or an endocrinologist (HR, 2.48 [CI, 1.69 to 3.63]) was associated with a higher likelihood of testing compared with primary care. Testing was associated with a 4-fold higher likelihood of initiating MRA therapy (HR, 4.10 [CI, 3.68 to 4.55]) and with better BP control over time.

LIMITATIONS

Predominantly male cohort, retrospective design, susceptibility of office BPs to misclassification, and lack of confirmatory testing for primary aldosteronism.

CONCLUSION

In a nationally distributed cohort of veterans with apparent treatment-resistant hypertension, testing for primary aldosteronism was rare and was associated with higher rates of evidence-based treatment with MRAs and better longitudinal BP control. The findings reinforce prior observations of low adherence to guideline-recommended practices in smaller health systems and underscore the urgent need for improved management of patients with treatment-resistant hypertension.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Prevalence, Subtype Classification, and Outcomes of Treatment of Primary Aldosteronism: A Prospective Study in China

OBJECTIVE

To investigate the prevalence of primary aldosteronism (PA) among participants with hypertension, evaluate the concordance of PA classification between adrenal computed tomography and adrenal venous sampling, and compare the outcomes of surgery and medication for unilateral PA.

METHODS

A prospective study was conducted among all inpatients with hypertension (n = 7594) at the National Center for Cardiovascular Diseases, China, from May 2016 to April 2018.

RESULTS

Of the 7594 participants, 8.12% (n = 617) with plasma aldosterone-renin ratio ≥3.7 were possible PA cases. Three hundred sixty-seven cases with plasma aldosterone-renin ratio ≥3.7 and plasma aldosterone concentration ≥10 ng/dL were confirmed using the recumbent saline infusion test (69.20%, 182 of 263) or the captopril challenge test (66.5%, 69 of 104, P > .05). The prevalence of PA was 3.31% (n = 251). Of the 251 patients with PA, all of them had multiple comorbidities, and 49.40% (n = 124) had spontaneous hypokalemia. The concordance of PA classification between adrenal computed tomography and adrenal venous sampling was only 47.11%. The patients' blood pressure declined to normal ranges in the adrenalectomy (85.71%, 30 of 35) and spironolactone (63.04%; 29 of 46) groups (P < .05). Furthermore, hypokalemia was normalized in the adrenalectomy (100.00%; 26 of 26) and spironolactone (94.74%; 18 of 19) groups.

CONCLUSION

It is necessary to incorporate PA screening into routine practice for those with hypertension in the Chinese population. This will assist in ensuring that the best therapeutic schedule based on PA subtypes is devised. Additionally, as a result, it may contribute to restoring the blood pressure levels and reducing the prevalence of comorbidities in these patients with PA.

Evolution of the Primary Aldosteronism Syndrome: Updating the Approach

CONTEXT

New approaches are needed to address the evolution of the primary aldosteronism syndrome and to increase its recognition. Herein, we review evidence indicating that primary aldosteronism is a prevalent syndrome that is mostly unrecognized, and present a pragmatic and pathophysiology-based approach to improve diagnosis and treatment.

METHODS

Evidence was gathered from published guidelines and studies identified from PubMed by searching for primary aldosteronism, aldosterone, renin, and hypertension. This evidence was supplemented by the authors' personal knowledge, research experience, and clinical encounters in primary aldosteronism.

INTERPRETATION OF EVIDENCE

Renin-independent aldosterone production is a prevalent phenotype that is diagnosed as primary aldosteronism when severe in magnitude, but is largely unrecognized when milder in severity. Renin-independent aldosterone production can be detected in normotensive and hypertensive individuals, and the magnitude of this biochemical phenotype parallels the magnitude of blood pressure elevation, the risk for incident hypertension and cardiovascular disease, and the likelihood and magnitude of blood pressure reduction with mineralocorticoid receptor antagonist therapy. Expansion of the indications to screen for primary aldosteronism, combined with the use of a pathophysiology-based approach that emphasizes inappropriate aldosterone production in the context of renin suppression, will substantially increase the diagnostic and therapeutic yields for primary aldosteronism.

CONCLUSIONS

The landscape of primary aldosteronism has evolved to recognize that it is a prevalent syndrome of renin-independent aldosterone production that contributes to the pathogenesis of hypertension and cardiovascular disease. Expanding screening indications and simplifying the diagnostic approach will enable implementation of targeted treatment for primary aldosteronism.

The Unrecognized Prevalence of Primary Aldosteronism: A Cross-sectional Study

BACKGROUND

Primary aldosteronism is a nonsuppressible renin-independent aldosterone production that causes hypertension and cardiovascular disease.

OBJECTIVE

To characterize the prevalence of nonsuppressible renin-independent aldosterone production, as well as biochemically overt primary aldosteronism, in relation to blood pressure.

DESIGN

Cross-sectional study.

SETTING

4 U.S. academic medical centers.

PARTICIPANTS

Participants with normotension (n = 289), stage 1 hypertension (n = 115), stage 2 hypertension (n = 203), and resistant hypertension (n = 408).

MEASUREMENTS

Participants completed an oral sodium suppression test, regardless of aldosterone or renin levels, as a confirmatory diagnostic for primary aldosteronism and to quantify the magnitude of renin-independent aldosterone production. Urinary aldosterone was measured in participants in high sodium balance with suppressed renin activity. Biochemically overt primary aldosteronism was diagnosed when urinary aldosterone levels were higher than 12 μg/24 h.

RESULTS

Every blood pressure category had a continuum of renin-independent aldosterone production, where greater severity of production was associated with higher blood pressure, kaliuresis, and lower serum potassium levels. Mean adjusted levels of urinary aldosterone were 6.5 μg/24 h (95% CI, 5.2 to 7.7 μg/24 h) in normotension, 7.3 μg/24 h (CI, 5.6 to 8.9 μg/24 h) in stage 1 hypertension, 9.5 μg/24 h (CI, 8.2 to 10.8 μg/24 h) in stage 2 hypertension, and 14.6 μg/24 h (CI, 12.9 to 16.2 μg/24 h) in resistant hypertension; corresponding adjusted prevalence estimates for biochemically overt primary aldosteronism were 11.3% (CI, 5.9% to 16.8%), 15.7% (CI, 8.6% to 22.9%), 21.6% (CI, 16.1% to 27.0%), and 22.0% (CI, 17.2% to 26.8%). The aldosterone-renin ratio had poor sensitivity and negative predictive value for detecting biochemically overt primary aldosteronism.

LIMITATION

Prevalence estimates rely on arbitrary and conventional thresholds, and the study population may not represent nationwide demographics.

CONCLUSION

The prevalence of primary aldosteronism is high and largely unrecognized. Beyond this categorical definition of primary aldosteronism, there is a prevalent continuum of renin-independent aldosterone production that parallels the severity of hypertension. These findings redefine the primary aldosteronism syndrome and implicate it in the pathogenesis of "essential" hypertension.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Prevalence of primary aldosteronism in hypertensive kidney transplant recipients: A cross-sectional study

Due to high prevalence of primary aldosteronism (PA) in the general hypertensive population, and its association with worse cardiovascular and renal outcomes, the 2016 Endocrine Society Guidelines explicitly recognize PA as a major public health issue requiring urgent attention. Its prevalence in hypertensive kidney transplant recipients (KTRs) is unknown. In this cross-sectional study, we screened KTRs with hypertension who were on ≥4 antihypertensive medications, on 3 antihypertensive medications with BP ≥ 140/90, and on potassium supplements, or were hypokalemic. 172 of 280 eligible patients successfully completed the testing. A positive screen for PA defined by an aldosterone-to-renin ratio of ≥20 and a plasma aldosterone concentration of >15 ng/dL yielded a prevalence of 15.7%. Potassium supplement requirement (52% vs 27%, P = .01) and hypokalemia (25.9% vs 4.8%, P < .01) were more common in patients who screened positive compared with those who screened negative. 67% of patients who screened positive were on potassium supplements and/or were hypokalemic. Our study is the first to systematically explore the prevalence of PA among the hypertensive KTR population, which has inherently high cardiovascular risk. Further studies are needed to determine the cardiovascular and renal risk attributable to PA, and define optimal therapy for KTRs with PA.

Hypokalemia and the Prevalence of Primary Aldosteronism

Hypokalemia is closely linked with the pathophysiology of primary aldosteronism (PA). Although hypokalemic PA is less common than the normokalemic course of the disease, hypokalemia is of particular importance for the manifestation and development of comorbidities. Specifically, a growing body of evidence demonstrates that hypokalemia in PA patients is associated with a more severe disease course regarding cardiovascular and metabolic morbidity and mortality. It is also well appreciated that low potassium levels per se can promote or exacerbate hypertension. The spectrum of hypokalemia-related symptoms ranges from asymptomatic courses to life-threatening conditions. Hypokalemia is found in 9-37% of all cases of PA with a predominance in patients with aldosterone producing adenoma. Conversely, hypokalemia resolves in almost 100% of cases after both, specific medical or surgical treatment of the disease. However, to date, high-level evidence about the prevalence of primary aldosteronism in a hypokalemic population is missing. Epidemiological data are expected from the recently launched IPAHK+study ("Incidence of Primary Aldosteronism in Patients with Hypokalemia").

Histological Characterization of Aldosterone-producing Adrenocortical Adenomas with Different Somatic Mutations

CONTEXT

Aldosterone-producing adrenocortical adenomas (APAs) are mainly composed of clear (lipid rich) and compact (eosinophilic) tumor cells. The detailed association between these histological features and somatic mutations (KCNJ5, ATP1A1, ATP2B3, and CACNA1D) in APAs is unknown.

OBJECTIVE

To examine the association between histological features and individual genotypes in APAs.

METHODS

Examination of 39 APAs subjected to targeted next-generation sequencing (11 KCNJ5, 10 ATP1A1, 10 ATP2B3, and 8 CACNA1D) and quantitative morphological and immunohistochemical (CYP11B2 and CYP17A1) analyses using digital imaging software.

RESULTS

KCNJ5- and ATP2B3-mutated APAs had clear cell dominant features (KCNJ5: clear 59.8% [54.4-64.6%] vs compact 40.2% (35.4-45.6%), P = .0022; ATP2B3: clear 54.3% [48.2-62.4 %] vs compact 45.7% (37.6-51.8 %), P = .0696). ATP1A1- and CACNA1D-mutated APAs presented with marked intratumoral heterogeneity. A significantly positive correlation of immunoreactivity was detected between CYP11B2 and CYP17A1 in tumor cells of KCNJ5-mutated APAs (P = .0112; ρ = 0.7237), in contrast, significantly inverse correlation was detected in ATP1A1-mutated APAs (P = .0025; ρ = -0.8667).

CONCLUSION

KCNJ5-mutated APAs, coexpressing CYP11B2 and CYP17A1, were more deviated in terms of zonation-specific differentiation of adrenocortical cells than ATP1A1- and ATP2B3-mutated APAs.

Application of CT texture analysis to assess the localization of primary aldosteronism

We performed present study to investigate whether the localization of primary aldosteronism (PA) can be predicted using quantitative texture analysis on unenhanced computed tomography (CT). Plain CT data of 82 PA patients (54 unilateral (right-sided:left-sided = 24:30), 28 bilateral) were analyzed retrospectively. After semi-automatically setting the region of interest to include the whole adrenal gland, texture analyses were performed with or without a Laplacian of Gaussian filter with various spatial scaling factors (SSFs). Logistic regression analysis was performed using the extracted histogram-based texture features to identify parameters capable of predicting excessive aldosterone production. The result of adrenal venous sampling served as gold standard in present study. As a result, logistic regression analysis indicated that the mean gray level intensity (p = 0.026), the mean value of the positive pixels (p = 0.003) in the unfiltered image, and entropy (p = 0.027) in the filtered image (SSF: 2 mm) were significant parameters. Using the model constructed by logistic regression analysis and the optimum cutoff value, the localization of PA (three multiple choices of left, right or bilateral) was determined with an accuracy of 67.1% (55/82). CT texture analysis may provide a potential avenue for less invasive prediction of the localization of PA.

The Association between eGFR and the Aldosterone-to-Renin Ratio and Its Effect on Screening for Primary Aldosteronism

OBJECTIVES

Long-term exposure to excessive aldosterone secretion from the adrenal gland may cause renal damage in patients with primary aldosteronism (PA). The aldosterone-to-renin ratio (ARR) may be significantly affected by renal function, especially in patients with renal damage related to long-term PA. The objective of this study was to investigate the association between the estimated glomerular filtration rate (eGFR) and ARR as well as its effect on screening for PA.

METHODS

This study was performed in Zhongshan Hospital, Fudan University, China. 803 patients with hypertension were consecutively recruited from 2012 to 2015. All participants underwent routine biochemical measurements, including plasma renin activity (PRA) and plasma aldosterone concentration (PAC). In all patients with a PAC higher than 10 ng/dl, a saline perfusion test was conducted, and a CT scan or adrenal venous sampling was also performed if needed. Receiver operating characteristic (ROC) analysis was conducted in all eGFR < 90 and eGFR ≥ 90 groups separately to determine the optimal cut-off values of ARR.

RESULTS

The optimal cut-off point for PA was an ARR of 40 ng/dl per ng/ml.h in the whole population, 52 ng/dl per ng/ml.h in subjects with an eGFR higher than 90 ml/min/1.73 m², and 18 ng/dl per ng/ml.h in subjects with an eGFR lower than 90 ml/min/1.73 m². Patients with an eGFR higher than 90 ml/min/1.73 m² had significantly lower PRA and higher ARR levels than patients with an eGFR lower than 90 ml/min/1.73 m² (P < 0.05).

CONCLUSIONS

Unsuppressed renin and lower ARR levels were associated with decreased eGFR in patients with primary aldosteronism. Diagnostic criteria of ARR by stratified eGFR may be an optimal strategy for the screening of primary aldosteronism.

CTNNB1 Knockdown Inhibits Cell Proliferation and Aldosterone Secretion Through Inhibiting Wnt/β-Catenin Signaling in H295R Cells

Aldosterone-producing adenomas (APA) is one of the causative factors of primary aldosteronism. Previous studies have suggested that there are somatic CTNNB1 mutations in APA, but the specific mechanism of CTNNB1 mutation in APA tumorigenesis and aldosterone secretion remains unclear. In the present study, human adrenocortical carcinoma cell line H295 R was used to establish stable CTNNB1 knockdown cell lines. Cell proliferation and aldosterone secretion of H295 R cells in response to angiotensin Ⅱ (Agn Ⅱ) were analyzed. We found that CTNNB1 knockdown reduced β-catenin expression and inhibited proliferation of H295 R cells. CTNNB1 knockdown inhibited Wnt/β-catenin signaling pathway and downregulated expression of downstream genes including axin 2, lymphoid enhancer binding factor 1 (LEF1), and cyclin D1. In addition, CTNNB1 knockdown decreased responses of H295 R cells to Agn Ⅱ and decreased aldosterone secretion. Our findings suggest that CTNNB1 knockdown can inhibit H295 R cell proliferation and decrease aldosterone secretion in the responses of H295 R cells to Ang II through inhibiting Wnt/β-catenin signaling pathway, indicating that targeting Wnt/β-catenin signaling pathway may be an important approach to decrease aldosterone secretion in the treatment of aldoster-producing adenomas.

Aldosterone as a mediator of severity in retinal vascular disease: Evidence and potential mechanisms

Diabetic retinopathy (DR) and retinal vein occlusion (RVO) are the two most common retinal vascular diseases and are major causes of vision loss and blindness worldwide. Recent and ongoing development of medical therapies including anti-vascular endothelial growth factor and corticosteroid drugs for treatment of these diseases have greatly improved the care of afflicted patients. However, severe manifestations of retinal vascular disease result in persistent macular edema, progressive retinal ischemia and incomplete visual recovery. Additionally, choroidal vascular diseases including neovascular age-related macular degeneration (NVAMD) and central serous chorioretinopathy (CSCR) cause vision loss for which current treatments are incompletely effective in some cases and highly burdensome in others. In recent years, aldosterone has gained attention as a contributor to the various deleterious effects of retinal and choroidal vascular diseases via a variety of mechanisms in several retinal cell types. The following is a review of the role of aldosterone in retinal and choroidal vascular diseases as well as our current understanding of the mechanisms by which aldosterone mediates these effects.

Case detection in primary aldosteronism: high-diagnostic value of the aldosterone-to-renin ratio when performed under standardized conditions

OBJECTIVE

The aldosterone-to-renin ratio is widely used and is the recommended screening modality for primary aldosteronism by the Endocrine Society Guideline. However, studies on its diagnostic accuracy have been inconsistent, which is mainly because of methodological limitations. We set out to evaluate this diagnostic value by using a highly standardized study protocol, which is in line with the Endocrine Society Guideline recommendations regarding indications for screening, testing conditions and reference standards in daily clinical practice.

METHODS

In this prospective study, 233 consecutive patients referred to the University Medical Center Utrecht with difficult-to-control hypertension were enrolled. In addition to aldosterone-to-renin ratio measurements, all patients underwent a saline infusion test as a reference standard. A plasma aldosterone concentration greater than 280 pmol/l after saline infusion was considered diagnostic for aldosteronism and the plasma renin activity was assessed to exclude patients with secondary aldosteronism from the final primary aldosteronism diagnosis.

RESULTS

Correlation of the aldosterone-to-renin ratio (cut-off >5) with primary aldosteronism diagnosis showed 16 true positive, 29 false positive, 188 true negative and 0 false negative aldosterone-to-renin ratios, resulting in a sensitivity of 100% (CI 75.9-100), specificity of 86.7% (CI 81.2-90.7), positive-predictive value of 35.6% (CI 22.3-51.3) and negative-predictive value of 100% (CI 97.5-100.0). The corresponding area under the curve was 0.933 (CI 0.900-0.966).

CONCLUSION

These findings show that the aldosterone-to-renin ratio is a good screening modality for primary aldosteronism and is without a high risk of missing a primary aldosteronism diagnosis whenever performed under well standardized conditions.

Screening of primary aldosteronism by clinical features and daily laboratory tests: combination of urine pH, sex, and serum K

OBJECTIVE

To develop and validate a scoring system for selection of patients who should proceed to endocrinologic examinations of primary aldosteronism in newly diagnosed hypertensive patients.

METHODS

A multivariate logistic regression analysis for primary aldosteronism was undertaken by use of seven possible primary aldosteronism markers, age less than 40 years, female sex, moderate-to-severe hypertension, hypokalemia, serum Na minus Cl at least 40 mmol/l, serum uric acid 237.92 μmol/l or less (4.0 mg/dl), and urine pH (U-pH) at least 7.0, in consecutive outpatients newly diagnosed with hypertension. The diagnostic criteria of primary aldosteronism were plasma aldosterone concentration-to-plasma renin activity ratio [ARR, (ng/dl)/(ng/ml per h)] at least 20 and at least one positive result in four types of challenge tests.

RESULTS

Of 130 patients, 24 were diagnosed with primary aldosteronism. The area under the receiver operating characteristic curve (AUC) for a logistic model incorporating all possible primary aldosteronism markers was 0.73 [95% confidence interval (CI): 0.61-0.85]. Removing high U-pH, female sex, and hypokalemia from the full model decreased the AUC by 0.059, 0.035, and 0.011, respectively. We devised pH of urine, female sex, low serum K (PFK) score, in which one point each was assigned to high U-pH, female sex, and hypokalemia. The prevalences of primary aldosteronism in patients with 0, 1, 2, and 3 points were 11, 14, 42, and 60%, respectively. In external validation datasets (n = 106), AUC of PFK score was significantly higher than that of hypokalemia alone (0.73, 95% CI: 0.63-0.83 vs. 0.53, 95% CI: 0.44-0.63, P < 0.01).

CONCLUSION

PFK score may be a better parameter than hypokalemia alone for identifying patients with a high probability of having primary aldosteronism.

The Expanding Spectrum of Primary Aldosteronism: Implications for Diagnosis, Pathogenesis, and Treatment

Primary aldosteronism is characterized by aldosterone secretion that is independent of renin and angiotensin II and sodium status. The deleterious effects of primary aldosteronism are mediated by excessive activation of the mineralocorticoid receptor that results in the well-known consequences of volume expansion, hypertension, hypokalemia, and metabolic alkalosis, but it also increases the risk for cardiovascular and kidney disease, as well as death. For decades, the approaches to defining, diagnosing, and treating primary aldosteronism have been relatively constant and generally focused on detecting and treating the more severe presentations of the disease. However, emerging evidence suggests that the prevalence of primary aldosteronism is much greater than previously recognized, and that milder and nonclassical forms of renin-independent aldosterone secretion that impart heightened cardiovascular risk may be common. Public health efforts to prevent aldosterone-mediated end-organ disease will require improved capabilities to diagnose all forms of primary aldosteronism while optimizing the treatment approaches such that the excess risk for cardiovascular and kidney disease is adequately mitigated. In this review, we present a physiologic approach to considering the diagnosis, pathogenesis, and treatment of primary aldosteronism. We review evidence suggesting that primary aldosteronism manifests across a wide spectrum of severity, ranging from mild to overt, that correlates with cardiovascular risk. Furthermore, we review emerging evidence from genetic studies that begin to provide a theoretical explanation for the pathogenesis of primary aldosteronism and a link to its phenotypic severity spectrum and prevalence. Finally, we review human studies that provide insights into the optimal approach toward the treatment of primary aldosteronism.

Adrenal venous sampling: the learning curve of a single interventionalist with 282 consecutive procedures

PURPOSE

Primary aldosteronism (PA) is a common cause of secondary hypertension. Adrenal venous sampling (AVS) is the gold standard for assessing laterality of PA, which is of paramount importance to decide adequate treatment. AVS is a technically complicated procedure with success rates ranging between 30% and 96%. The aim of this study was to investigate the success rate of AVS over time, performed by a single interventionalist.

METHODS

This was a retrospective study based on consecutive AVS procedures performed by a single operator between September 2005 and June 2016. Data on serum concentrations of aldosterone and cortisol from right and left adrenal vein, inferior vena cava, and peripheral vein were collected and selectivity index (SI) calculated. Successful AVS was defined as SI > 5.

RESULTS

In total, 282 AVS procedures were performed on 269 patients, 168 men (62%) and 101 women (38%), with a mean age of 55±11 years (range, 26-78 years). Out of 282 AVS procedures, 259 were successful, giving an overall success rate of 92%. The most common reason for failure was inability to localize the right adrenal vein (n=16; 76%). The success rates were 63%, 82%, and 94% during the first, second, and third years, respectively. During the last 8 years the success rate was 95%, and on average 27 procedures were performed annually.

CONCLUSION

Satisfactory AVS success rate was achieved after approximately 36 procedures and satisfactory success rate was maintained by performing approximately 27 procedures annually. AVS should be limited to few operators that perform sufficiently large number of procedures to achieve, and maintain, satisfactory AVS success rate.

The Spectrum of Subclinical Primary Aldosteronism and Incident Hypertension: A Cohort Study

BACKGROUND

Primary aldosteronism is recognized as a severe form of renin-independent aldosteronism that results in excessive mineralocorticoid receptor (MR) activation.

OBJECTIVE

To investigate whether a spectrum of subclinical renin-independent aldosteronism that increases risk for hypertension exists among normotensive persons.

DESIGN

Cohort study.

SETTING

National community-based study.

PARTICIPANTS

850 untreated normotensive participants in MESA (Multi-Ethnic Study of Atherosclerosis) with measurements of serum aldosterone and plasma renin activity (PRA).

MEASUREMENTS

Longitudinal analyses investigated whether aldosterone concentrations, in the context of physiologic PRA phenotypes (suppressed, ≤0.50 µg/L per hour; indeterminate, 0.51 to 0.99 µg/L per hour; unsuppressed, ≥1.0 µg/L per hour), were associated with incident hypertension (defined as systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or initiation of antihypertensive medications). Cross-sectional analyses investigated associations between aldosterone and MR activity, assessed via serum potassium and urinary fractional excretion of potassium.

RESULTS

A suppressed renin phenotype was associated with a higher rate of incident hypertension than other PRA phenotypes (incidence rates per 1000 person-years of follow-up: suppressed renin phenotype, 85.4 events [95% CI, 73.4 to 99.3 events]; indeterminate renin phenotype, 53.3 events [CI, 42.8 to 66.4 events]; unsuppressed renin phenotype, 54.5 events [CI, 41.8 to 71.0 events]). With renin suppression, higher aldosterone concentrations were independently associated with an increased risk for incident hypertension, whereas no association between aldosterone and hypertension was seen when renin was not suppressed. Higher aldosterone concentrations were associated with lower serum potassium and higher urinary excretion of potassium, but only when renin was suppressed.

LIMITATION

Sodium and potassium were measured several years before renin and aldosterone.

CONCLUSION

Suppression of renin and higher aldosterone concentrations in the context of this renin suppression are associated with an increased risk for hypertension and possibly also with increased MR activity. These findings suggest a clinically relevant spectrum of subclinical primary aldosteronism (renin-independent aldosteronism) in normotension.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Coexistence of Primary Hyperaldosteronism and Graves' Disease, a Rare Combination of Endocrine Disorders: Is It beyond a Coincidence-A Case Report and Review of the Literature

BACKGROUND

Primary hyperaldosteronism is a known cause for secondary hypertension. In addition to its effect on blood pressure, aldosterone exhibits proinflammatory actions and plays a role in immunomodulation/development of autoimmunity. Recent researches also suggest significant thyroid dysfunction among patients with hyperaldosteronism, but exact causal relationship is not established. Autoimmune hyperthyroidism (Graves' disease) and primary hyperaldosteronism rarely coexist but underlying mechanisms associating the two are still unclear.

CASE PRESENTATION

A 32-year-old Sri Lankan female was evaluated for new onset hypertension in association with hypokalemia. She also had features of hyperthyroidism together with high TSH receptor antibodies suggestive of Graves' disease. On evaluation of persistent hypokalemia and hypertension, primary hyperaldosteronism due to right-sided adrenal adenoma was diagnosed. She was rendered euthyroid with antithyroid drugs followed by right-sided adrenalectomy. Antithyroid drugs were continued up to 12 months, after which the patient entered remission of Graves' disease.

CONCLUSION

Autoimmune hyperthyroidism and primary hyperaldosteronism rarely coexist and this case report adds to the limited number of cases documented in the literature. Underlying mechanism associating the two is still unclear but possibilities of autoimmune mechanisms and autoantibodies warrant further evaluation and research.

On the effect of hyperaldosteronism-inducing mutations in Na/K pumps

Mutated Na/K pumps in adrenal adenomas are thought to cause hyperaldosteronism via a gain-of-function effect involving a depolarizing inward current. The findings of Meyer et al. suggest instead that the common mechanism by which Na/K pump mutants lead to hyperaldosteronism is a loss-of-function.

Primary aldosteronism, a condition in which too much aldosterone is produced and that leads to hypertension, is often initiated by an aldosterone-producing adenoma within the zona glomerulosa of the adrenal cortex. Somatic mutations of ATP1A1, encoding the Na/K pump α1 subunit, have been found in these adenomas. It has been proposed that a passive inward current transported by several of these mutant pumps is a "gain-of-function" activity that produces membrane depolarization and concomitant increases in aldosterone production. Here, we investigate whether the inward current through mutant Na/K pumps is large enough to induce depolarization of the cells that harbor them. We first investigate inward currents induced by these mutations in Xenopus Na/K pumps expressed in Xenopus oocytes and find that these inward currents are similar in amplitude to wild-type outward Na/K pump currents. Subsequently, we perform a detailed functional evaluation of the human Na/K pump mutants L104R, delF100-L104, V332G, and EETA963S expressed in Xenopus oocytes. By combining two-electrode voltage clamp with [³H]ouabain binding, we measure the turnover rate of these inward currents and compare it to the turnover rate for outward current through wild-type pumps. We find that the turnover rate of the inward current through two of these mutants (EETA963S and L104R) is too small to induce significant cell depolarization. Electrophysiological characterization of another hyperaldosteronism-inducing mutation, G99R, reveals the absence of inward currents under many different conditions, including in the presence of the regulator FXYD1 as well as with mammalian ionic concentrations and body temperatures. Instead, we observe robust outward currents, but with significantly reduced affinities for intracellular Na⁺ and extracellular K⁺. Collectively, our results point to loss-of-function as the common mechanism for the hyperaldosteronism induced by these Na/K pump mutants.

Hypertension outcomes of adrenalectomy in patients with primary aldosteronism: a systematic review and meta-analysis

BACKGROUND

The hypertension cure rate of unilateral adrenalectomy in primary aldosteronism (PA) patients varies widely in existing studies.

METHODS

We conducted an observational meta-analysis to summarize the pooled hypertension cure rate of unilateral adrenalectomy in PA patients. Comprehensive electronic searches of PubMed, Embase, Cochrane, China National Knowledge Internet (CNKI), WanFang, SinoMed and Chongqing VIP databases were performed from initial state to May 20, 2016. We manually selected eligible studies from references in accordance with the inclusion criteria. The pooled hypertension cure rate of unilateral adrenalectomy in PA patients was calculated using the DerSimonian-Laird method to produce a random-effects model.

RESULTS

Forty-three studies comprising approximately 4000 PA patients were included. The pooled hypertension cure rate was 50.6% (95% CI: 42.9-58.2%) for unilateral adrenalectomy in PA. Subgroup analyses showed that the hypertension cure rate was 61.3% (95% CI: 49.4-73.3%) in Chinese studies and 43.7% (95% CI: 38.0-49.4%) for other countries. Furthermore, the hypertension cure rate at 6-month follow-up was 53.3% (95% CI: 36.0-70.5%) and 49.6% (95% CI: 40.9-58.3%) for follow-up exceeding 6 months. The pooled hypertension cure rate was 50.9% (95% CI: 40.5-61.3%) from 2001 to 2010 and 50.2% (95% CI: 39.0-61.5%) from 2011 to 2016.

CONCLUSIONS

The hypertension cure rate for unilateral adrenalectomy in PA is not optimal. Large clinical trials are required to verify the utility of potential preoperative predictors in developing a novel and effective prediction model.

CTNNB1 Mutation in Aldosterone Producing Adenoma

Discoveries of somatic mutations permit the recognition of subtypes of aldosterone-producing adenomas (APAs) with distinct clinical presentations and pathological features. Catenin β1 (CTNNB1) mutation in APAs has been recently described and discussed in the literature. However, significant knowledge gaps still remain regarding the prevalence, clinical characteristics, pathophysiology, and outcomes in APA patients harboring CTNNB1 mutations. Aberrant activation of the Wnt/β-catenin signaling pathway will further modulate tumorigenesis. We also discuss the recent knowledge of CTNNB1 mutation in adrenal adenomas.

Somatic and inherited mutations in primary aldosteronism

Primary aldosteronism (PA), the most common form of secondary hypertension, is caused in the majority of cases by unilateral aldosterone-producing adenoma (APA) or bilateral adrenal hyperplasia. Over the past few years, somatic mutations in KCNJ5, CACNA1D, ATP1A1 and ATP2B3 have been proven to be associated with APA development, representing more than 50% of sporadic APA. The identification of these mutations has allowed the development of a model for APA involving modification on the intracellular ionic equilibrium and regulation of cell membrane potential, leading to autonomous aldosterone overproduction. Furthermore, somatic CTNNB1 mutations have also been identified in APA, but the link between these mutations and APA development remains unknown. The sequence of events responsible for APA formation is not completely understood, in particular, whether a single hit or a double hit is responsible for both aldosterone overproduction and cell proliferation. Germline mutations identified in patients with early-onset PA have expanded the classification of familial forms (FH) of PA. The description of germline KCNJ5 and CACNA1H mutations has identified FH-III and FH-IV based on genetic findings; germline CACNA1D mutations have been identified in patients with very early-onset PA and severe neurological abnormalities. This review summarizes current knowledge on the genetic basis of PA, the association of driver gene mutations and clinical findings and in the contribution to patient care, plus the current understanding on the mechanisms of APA development.

Rapid Screening of Primary Aldosteronism by a Novel Chemiluminescent Immunoassay

Measurement of plasma aldosterone and renin concentration, or activity, is useful for selecting antihypertensive agents and detecting hyperaldosteronism in hypertensive patients. However, it takes several days to get results when measured by radioimmunoassay and development of more rapid assays has been long expected. We have developed chemiluminescent enzyme immunoassays enabling the simultaneous measurement of both aldosterone and renin concentrations in 10 minutes by a fully automated assay using antibody-immobilized magnetic particles with quick aggregation and dispersion. We performed clinical validation of diagnostic ability of this newly developed assay-based screening of 125 patients with primary aldosteronism from 97 patients with essential hypertension. Results of this novel assay significantly correlated with the results of radioimmunoassay (aldosterone, active renin concentration, and renin activity) and liquid chromatography-tandem mass spectrometry (aldosterone). The analytic sensitivity of this particularly novel active renin assay was 0.1 pg/mL, which was better than that of radioimmunoassay (2.0 pg/mL). The ratio of aldosterone-to-renin concentrations of 6.0 (ng/dL per pg/mL) provided 92.0% sensitivity and 76.3% specificity as a cutoff for differentiating primary aldosteronism from essential hypertension. This novel measurement is expected to be a clinically reliable alternative for conventional radioimmunoassay and to provide better throughput and cost effectiveness in diagnosis of hyperaldosteronism from larger numbers of hypertensive patients in clinical settings.

Steroid metabolome analysis reveals prevalent glucocorticoid excess in primary aldosteronism

BACKGROUND

Adrenal aldosterone excess is the most common cause of secondary hypertension and is associated with increased cardiovascular morbidity. However, adverse metabolic risk in primary aldosteronism extends beyond hypertension, with increased rates of insulin resistance, type 2 diabetes, and osteoporosis, which cannot be easily explained by aldosterone excess.

METHODS

We performed mass spectrometry-based analysis of a 24-hour urine steroid metabolome in 174 newly diagnosed patients with primary aldosteronism (103 unilateral adenomas, 71 bilateral adrenal hyperplasias) in comparison to 162 healthy controls, 56 patients with endocrine inactive adrenal adenoma, 104 patients with mild subclinical, and 47 with clinically overt adrenal cortisol excess. We also analyzed the expression of cortisol-producing CYP11B1 and aldosterone-producing CYP11B2 enzymes in adenoma tissue from 57 patients with aldosterone-producing adenoma, employing immunohistochemistry with digital image analysis.

RESULTS

Primary aldosteronism patients had significantly increased cortisol and total glucocorticoid metabolite excretion (all P < 0.001), only exceeded by glucocorticoid output in patients with clinically overt adrenal Cushing syndrome. Several surrogate parameters of metabolic risk correlated significantly with glucocorticoid but not mineralocorticoid output. Intratumoral CYP11B1 expression was significantly associated with the corresponding in vivo glucocorticoid excretion. Unilateral adrenalectomy resolved both mineralocorticoid and glucocorticoid excess. Postoperative evidence of adrenal insufficiency was found in 13 (29%) of 45 consecutively tested patients.

CONCLUSION

Our data indicate that glucocorticoid cosecretion is frequently found in primary aldosteronism and contributes to associated metabolic risk. Mineralocorticoid receptor antagonist therapy alone may not be sufficient to counteract adverse metabolic risk in medically treated patients with primary aldosteronism.

FUNDING

Medical Research Council UK, Wellcome Trust, European Commission.

Genetic characterization of a mouse line with primary aldosteronism

In an attempt to define novel genetic loci involved in the pathophysiology of primary aldosteronism, a mutagenesis screen after treatment with the alkylating agent N-ethyl-N-nitrosourea was established for the parameter aldosterone. One of the generated mouse lines with hyperaldosteronism was phenotypically and genetically characterized. This mouse line had high aldosterone levels but normal creatinine and urea values. The steroidogenic enzyme expression levels in the adrenal gland did not differ significantly among phenotypically affected and unaffected mice. Upon exome sequencing, point mutations were identified in seven candidate genes (Sspo, Dguok, Hoxaas2, Clstn3, Atm, Tipin and Mapk6). Subsequently, animals were stratified into wild-type and mutated groups according to their genotype for each of these candidate genes. A correlation of their genotypes with the respective aldosterone, aldosterone-to-renin ratio (ARR), urea and creatinine values as well as steroidogenic enzyme expression levels was performed. Aldosterone values were significantly higher in animals carrying mutations in four different genes (Sspo, Dguok, Hoxaas2 and Clstn3) and associated statistically significant adrenal Cyp11b2 overexpression as well as increased ARR was present only in mice with Sspo mutation. In contrast, mutations of the remaining candidate genes (Atm, Tipin and Mapk6) were associated with lower aldosterone values and lower Hsd3b6 expression levels. In summary, these data demonstrate association between the genes Sspo, Dguok, Hoxaas2 and Clstn3 and hyperaldosteronism. Final proofs for the causative nature of the mutations have to come from knock-out and knock-in experiments.

Hypertension: The role of biochemistry in the diagnosis and management

Hypertension is defined as a persistently elevated blood pressure ≥140/90mmHg. It is an important treatable risk factor for cardiovascular disease, with a high prevalence in the general population. The most common cause, essential hypertension, is a widespread disease - however, secondary hypertension is under investigated and under diagnosed. Collectively, hypertension is referred to as a "silent killer" - frequently it displays no overt symptomatology. It is a leading risk factor for death and disability globally, with >40% of persons aged over 25 having hypertension. A vast spectrum of conditions result in hypertension spanning essential through resistant, to patients with an overt endocrine cause. A significant number of patients with hypertension have multiple cardiovascular risk factors at the time of presentation. Both routine and specialised biochemical investigations are paramount for the evaluation of these patients and their subsequent management. Biochemical testing serves to identify those hypertensive individuals who are at higher risk on the basis of evidence of dysglycaemia, dyslipidaemia, renal impairment, or target organ damage and to exclude identifiable causes of hypertension. The main target of biochemical testing is the identification of patients with a specific and treatable aetiology of hypertension. Information gleaned from biochemical investigation is used to risk stratify patients and tailor the type and intensity of subsequent management and treatment. We review the approach to the biochemical investigation of patients presenting with hypertension and propose a diagnostic algorithm for work-up.

A cross-sectional study of the effects of β-blocker therapy on the interpretation of the aldosterone/renin ratio: can dosing regimen predict effect?

CONTEXT AND AIM

Aldosterone/renin ratio (ARR) is used as the primary screening tool for primary aldosteronism. Its interpretation is often challenging because of the interference of antihypertensive medication. β-blocker therapy suppresses renin production by inhibiting β-adrenergic receptors in the juxtaglomerular apparatus of the kidney and consequently aldosterone secretion (to a lesser extent). Therefore, β-blocker therapy has the potential to elevate the ARR. The aim of this study was to investigate whether or not the effect of β-blocker therapy on the ARR could be predicted from the dosing regimen.

METHODS

A prospective cross-sectional study was conducted. Participants were stratified into one of four groups (control/low/medium/high) based on the quantity of β-blocker prescribed. ARR was calculated from renin/aldosterone, measured using two assay systems.

RESULTS

Eighty-nine volunteers were recruited to our study. In the control group, zero patients had a positive ARR using plasma renin activity (PRA)/direct renin concentration (DRC). In the low, medium, and high-dose β-blocker groups between 8-25% of patients demonstrated screen positive ARR results for primary aldosteronism using DRC and PRA. DRC was significantly lower in patients in the medium/high-dose groups and PRA significantly lower in the low/medium/high-dose groups compared with controls. ARR using DRC was significantly higher in the medium/high-dose groups and ARR using PRA was significantly higher in the low/medium/high-dose groups compared with controls.

CONCLUSION

Our study suggests that β-blocker therapy is associated with an increased risk of positive ARR screens for primary aldosteronism irrespective of the dose of β-blocker prescribed, in patients in whom it is clinically reasonable to expect that primary aldosteronism may be present.

PRKACA Somatic Mutations Are Rare Findings in Aldosterone-Producing Adenomas

CONTEXT

Somatic mutations have been found causative for endocrine autonomy in aldosterone-producing adenomas (APAs). Whereas mutations of PRKACA (catalytic subunit of protein kinase A) have been identified in cortisol-producing adenomas, the presence of PRKACA variants in APAs is unknown, especially in those that display cosecretion of cortisol.

OBJECTIVE

The objective of the study was to investigate PRKACA somatic variants identified in APA cases.

DESIGN

Identification of PRKACA somatic variants in APAs by whole-exome sequencing followed by in vitro analysis of the enzymatic activity of PRKACA variants and functional characterization by double immunofluorescence of CYP11B2 and CYP11B1 expression in the corresponding tumor tissues.

SETTING AND PATIENTS

APA tissues were collected from 122 patients who underwent unilateral adrenalectomy for primary aldosteronism between 2005 and 2015 at a single institution.

RESULTS

PRKACA somatic mutations were identified in two APA cases (1.6%). One APA carried a newly identified p.His88Asp variant, whereas in a second case, a p.Leu206Arg mutation was found, previously described only in cortisol-producing adenomas with overt Cushing's syndrome. Functional analysis showed that the p.His88Asp variant was not associated with gain of function. Although CYP11B2 was strongly expressed in the p.His88Asp-mutated APA, the p.Leu206Arg carrying APA predominantly expressed CYP11B1. Accordingly, biochemical Cushing's syndrome was present only in the patient with the p.Leu206Arg mutation. After adrenalectomy, both patients improved with a reduced number of antihypertensive medications and normalized serum potassium levels.

CONCLUSIONS

We describe for the first time PRKACA mutations as rare findings associated with unilateral primary aldosteronism. As cortisol cosecretion occurs in a subgroup of APAs, other molecular mechanisms are likely to exist.

Clinical validation for the aldosterone-to-renin ratio and aldosterone suppression testing using simultaneous fully automated chemiluminescence immunoassays

BACKGROUND

As larger numbers of hypertensive patients are screened for primary aldosteronism with the aldosterone-to-renin ratio (ARR), automated analyzers present a practical solution for many laboratories. We report the method-specific ARR cutoff determined with direct, automated chemiluminescence immunoassays allowing the simultaneous measurement of plasma aldosterone concentrations (PACs) and plasma renin concentrations (PRCs).

METHODS

Method comparisons to commonly employed assays and tandem mass spectrometry were undertaken. Patients were previously diagnosed based on the local ARR cutoff of 1.2 (ng/dl)/(μIU/ml) in samples collected in upright seated position. Lack of aldosterone suppression in response to salt load to less than 5 ng/dl confirmed primary aldosteronism. For the new assays, the optimal ARR cutoff was established in 152 patients with essential hypertension, 93 with primary aldosteronism and 147 normotensive patients. Aldosterone suppression was assessed in 73 essential hypertensive and 46 primary aldosteronism patients.

RESULTS

PAC and PRC were significantly correlated to values determined with currently available methods (P < 0.001). In patients with primary aldosteronism, patients with essential hypertension and controls, mean (95% confidence interval) PAC was 28.4 (25.4-31.8), 6.4 (5.9-6.9) and 6.2 (5.6-6.9) ng/dl, respectively. In the same groups, PRC was 6.6 (5.6-7.7), 12.9 (11.2-14.8) and 26.5 (22.2-31.5) μIU/ml. An ARR cutoff of 1.12 provided 98.9% sensitivity and 78.9% specificity. Employing the new assay aldosterone suppression confirmed the diagnosis of primary aldosteronism and essential hypertension using the cutoff of 5 ng/dl.

CONCLUSION

Our data demonstrate that the new assays present a convenient alternative for the measurement of PAC and PRC on a single automated analyzer. Availability of these simultaneous assays should facilitate screening and diagnosis of primary aldosteronism.

The Management of Primary Aldosteronism: Case Detection, Diagnosis, and Treatment: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

To develop clinical practice guidelines for the management of patients with primary aldosteronism.

PARTICIPANTS

The Task Force included a chair, selected by the Clinical Guidelines Subcommittee of the Endocrine Society, six additional experts, a methodologist, and a medical writer. The guideline was cosponsored by American Heart Association, American Association of Endocrine Surgeons, European Society of Endocrinology, European Society of Hypertension, International Association of Endocrine Surgeons, International Society of Endocrinology, International Society of Hypertension, Japan Endocrine Society, and The Japanese Society of Hypertension. The Task Force received no corporate funding or remuneration.

EVIDENCE

We searched for systematic reviews and primary studies to formulate the key treatment and prevention recommendations. We used the Grading of Recommendations, Assessment, Development, and Evaluation group criteria to describe both the quality of evidence and the strength of recommendations. We used "recommend" for strong recommendations and "suggest" for weak recommendations.

CONSENSUS PROCESS

We achieved consensus by collecting the best available evidence and conducting one group meeting, several conference calls, and multiple e-mail communications. With the help of a medical writer, the Endocrine Society's Clinical Guidelines Subcommittee, Clinical Affairs Core Committee, and Council successfully reviewed the drafts prepared by the Task Force. We placed the version approved by the Clinical Guidelines Subcommittee and Clinical Affairs Core Committee on the Endocrine Society's website for comments by members. At each stage of review, the Task Force received written comments and incorporated necessary changes.

CONCLUSIONS

For high-risk groups of hypertensive patients and those with hypokalemia, we recommend case detection of primary aldosteronism by determining the aldosterone-renin ratio under standard conditions and recommend that a commonly used confirmatory test should confirm/exclude the condition. We recommend that all patients with primary aldosteronism undergo adrenal computed tomography as the initial study in subtype testing and to exclude adrenocortical carcinoma. We recommend that an experienced radiologist should establish/exclude unilateral primary aldosteronism using bilateral adrenal venous sampling, and if confirmed, this should optimally be treated by laparoscopic adrenalectomy. We recommend that patients with bilateral adrenal hyperplasia or those unsuitable for surgery should be treated primarily with a mineralocorticoid receptor antagonist.

Regulation of aldosterone secretion by Cav1.3

Aldosterone-producing adenomas (APAs) vary in phenotype and genotype. Zona glomerulosa (ZG)-like APAs frequently have mutations of an L-type calcium channel (LTCC) Ca_V1.3. Using a novel antagonist of Ca_V1.3, compound 8, we investigated the role of Ca_V1.3 on steroidogenesis in the human adrenocortical cell line, H295R, and in primary human adrenal cells. This investigational drug was compared with the common antihypertensive drug nifedipine, which has 4.5-fold selectivity for the vascular LTCC, Ca_V1.2, over Ca_V1.3. In H295R cells transfected with wild-type or mutant Ca_V1.3 channels, the latter produced more aldosterone than wild-type, which was ameliorated by 100 μM of compound 8. In primary adrenal and non-transfected H295R cells, compound 8 decreased aldosterone production similar to high concentration of nifedipine (100 μM). Selective Ca_V1.3 blockade may offer a novel way of treating primary hyperaldosteronism, which avoids the vascular side effects of Ca_V1.2-blockade, and provides targeted treatment for ZG-like APAs with mutations of Ca_V1.3.

SFE/SFHTA/AFCE consensus on primary aldosteronism, part 1: Epidemiology of PA, who should be screened for sporadic PA?

Depending on the study, the prevalence of primary aldosteronism (PA) in patients with hypertension varies from 6 to 18%. Prevalence is higher in each of the following conditions, any one of which requires screening for PA: severe hypertension (systolic blood pressure [BP]≥180mmHg and/or diastolic BP≥110mmHg); resistant hypertension (systolic BP≥140mmHg and/or diastolic BP≥90mmHg despite adherence to a tritherapy including a thiazide diuretic); hypertension associated with hypokalemia (either spontaneous or associated with a diuretic); Hypertension or hypokalemia associated with adrenal incidentaloma. It should be borne in mind that PA can induce hypertension without hypokalemia or, less frequently, hypokalemia without hypertension. Finally, as cardiovascular and renal morbidity in PA is greater than in essential hypertension of equivalent level, screening for PA is indicated when cardiovascular or renal morbidity is more severe than predicted from BP level.

β-Blocker withdrawal is preferable for accurate interpretation of the aldosterone-renin ratio in chronically treated hypertension

OBJECTIVES

To evaluate the effects of β-adrenoreceptor antagonists (β-blockers) on the aldosterone-renin ratio (ARR) in the context of antihypertensive polypharmacy in chronic hypertension. To determine the optimal duration of β-blocker withdrawal required to normalize the ARR.

DESIGN

A prospective, longitudinal study design was employed investigating two groups whom either remained on or withdrew from β-blocker therapy.

METHODS

Hypertensive individuals taking β-blockers and a combination of thiazide diuretics, α1-blockers, calcium channel antagonists and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker were recruited and followed over 10-12 weeks. β-Blockers were withdrawn at the first visit. Blood pressure (BP) was measured at each visit and blood drawn serially for measurement of plasma renin activity (PRA), direct renin concentration (DRC) and aldosterone. BP was optimized by maximizing non-renin-suppressing antihypertensives. Main outcomes were ARR, DRC, PRA and aldosterone. Plasma renin activity was calculated from angiotensin I measured using radioimmunoassay (RIA), DRC was measured using chemiluminescent immunoassay assay, and aldosterone was measured using both RIA and Chemilluminescence Assay (CIL).

RESULTS

False-positive ARR for primary aldosteronism (PA) occurred in 31% of patients taking β-blockers. ARR returned to normal following β-blocker withdrawal resulting from an increase in the DRC and PRA without affecting aldosterone. The optimum time for β-blocker withdrawal was 2 weeks when using DRC and 3 weeks for PRA. β-Blocker withdrawal did not adversely affect blood pressure.

CONCLUSION

Raised ARR consequent to β-blocker therapy causes false-positive screening for PA. Where β-blockers can be safely withdrawn, this effect is reversed within 2-3 weeks depending on whether DRC or PRA is used to calculate ARR.

Activating mutations in CTNNB1 in aldosterone producing adenomas

Primary aldosteronism (PA) is the most common cause of secondary hypertension with a prevalence of 5–10% in unreferred hypertensive patients. Aldosterone producing adenomas (APAs) constitute a large proportion of PA cases and represent a surgically correctable form of the disease. The WNT signaling pathway is activated in APAs. In other tumors, a frequent cause of aberrant WNT signaling is mutation in the CTNNB1 gene coding for β-catenin. Our objective was to screen for CTNNB1 mutations in a well-characterized cohort of 198 APAs. Somatic CTNNB1 mutations were detected in 5.1% of the tumors, occurring mutually exclusive from mutations in KCNJ5, ATP1A1, ATP2B3 and CACNA1D. All of the observed mutations altered serine/threonine residues in the GSK3β binding domain in exon 3. The mutations were associated with stabilized β-catenin and increased AXIN2 expression, suggesting activation of WNT signaling. By CYP11B2 mRNA expression, CYP11B2 protein expression, and direct measurement of aldosterone in tumor tissue, we confirmed the ability for aldosterone production. This report provides compelling evidence that aberrant WNT signaling caused by mutations in CTNNB1 occur in APAs. This also suggests that other mechanisms that constitutively activate the WNT pathway may be important in APA formation.

Different Somatic Mutations in Multinodular Adrenals With Aldosterone-Producing Adenoma

Primary aldosteronism is the most common form of secondary hypertension. Somatic mutations in KCNJ5, ATP1A1, ATP2B3, and CACNA1D are found in aldosterone-producing adenoma. In addition, adrenals with aldosterone-producing adenomas show cortical remodeling and frequently multiple secondary nodules. Our aim was to investigate whether different aldosterone-producing nodules from the same adrenal share the same mutational status. Aldosterone synthase expression was assessed in multinodular adrenals from 27 patients. DNA of 37 aldosterone-producing secondary nodules was extracted from formalin-fixed paraffin-embedded tissues and genotyped for KCNJ5, ATP1A1, ATP2B3, and CACNA1D mutations. Among 17 adrenals with a somatic mutation in the principal nodule, 4 showed the same mutation in a secondary nodule, whereas 10 had no mutation in any of the known genes. In 1 adrenal harboring the KCNJ5 p.Gly151Arg mutation in the principal nodule, the same mutation was present in 2 secondary nodules, but no mutation was found in a third nodule. Finally, in 2 adrenals with a CACNA1D mutation in the principal nodule, a KCNJ5 mutation was identified in the secondary nodule. Among 10 adrenals without mutations in the principal nodule, 1 carried a KCNJ5 mutation in the secondary nodule. No mutations were detected in 7 aldosterone-producing cell clusters from 6 adrenals. No association was observed between the presence of mutations in secondary nodules and clinical parameters. In conclusion, different mutations are found in different aldosterone-producing nodules from the same adrenal, suggesting that somatic mutations are independent events triggered by mechanisms that remain to be identified.

Somatic mutations of the ATP1A1 gene and aldosterone-producing adenomas

Primary aldosteronism is the most common form of secondary hypertension. It affects approximately 10% of patients with hypertension and causes greater cardiovascular morbidity and mortality compared to essential hypertension of similar severity and duration. The cause of primary aldosteronism in about half of these patients is an aldosterone-producing adenoma; over half of these adenomas have mutations in one of several ion channels and pumps, including the potassium channel KCNJ5, calcium channel Cav1.3, α1 subunit of the sodium potassium ATPase, and membrane calcium ATPase 3. This review concentrates on the molecular and physiological mechanisms by which mutations of the ATP1A1 gene increase aldosterone production.

Progress in aldosteronism: a review of the prevalence of primary aldosteronism in pre-hypertension and hypertension

Primary aldosteronism (PA) secondary to excessive and/or autonomous aldosterone secretion from the renin-angiotensin system accounts for ∼10% of cases of hypertension and is primarily caused by bilateral adrenal hyperplasia (BAH) or aldosterone-producing adenomas (APAs). Although the diagnosis has traditionally been supported by low serum potassium levels, normokalaemic and even normotensive forms of PA have been identified expanding further the clinical phenotype. Moreover, recent evidence has shown that serum aldosterone correlates with increased blood pressure (BP) in the general population and even moderately raised aldosterone levels are linked to increased cardiovascular morbidity and mortality. In addition, aldosterone antagonists are effective in BP control even in patients without evidence of dysregulated aldosterone secretion. These findings indicate a higher prevalence of aldosterone excess among hypertensive patients than previously considered that could be attributed to disease heterogeneity, aldosterone level fluctuations related to an ACTH effect or inadequate sensitivity of current diagnostic means to identify apparent aldosterone excess. In addition, functioning aberrant receptors expressed in the adrenal tissue have been found in a subset of PA cases that could also be related to its pathogenesis. Recently a number of specific genetic alterations, mainly involving ion homeostasis across the membrane of zona glomerulosa, have been detected in ∼50% of patients with APAs. Although specific genotype/phenotype correlations have not been clearly identified, differential expression of these genetic alterations could also account for the wide clinical phenotype, variations in disease prevalence and performance of diagnostic tests. In the present review, we critically analyse the current means used to diagnose PA along with the role that ACTH, aberrant receptor expression and genetic alterations may exert, and provide evidence for an increased prevalence of aldosterone dysregulation in patients with essential hypertension and pre-hypertension.

Post-saline infusion test aldosterone levels indicate severity and outcome in primary aldosteronism

OBJECTIVE

The saline infusion test (SIT) is widely used as a confirmatory test for primary aldosteronism (PA). SIT results are judged as follows: post-test aldosterone levels <50 ng/l exclude PA, whereas levels >50 ng/l confirm PA. We hypothesized that post-SIT aldosterone concentrations indicate the severity of PA and might predict outcome.

DESIGN

The study includes 256 PA patients of the German Conn's Registry who prospectively underwent SIT. The data of 126 patients with complete follow-up of 1.2±0.3 years after diagnosis were analyzed. The patients were divided into two groups with post-SIT aldosterone levels of 50-100 ng/l (group 1; n=38) and of >100 ng/l (group 2; n=88).

RESULTS

Patients in group 2 had a significantly shorter duration of hypertension (7.5 vs 11.7 years (median), P=0.014), higher systolic blood pressure (BP; 151±16 vs 143±17 mmHg, P=0.036), lower serum potassium (3.3±0.6 vs 3.5±0.4 mmol/l, P=0.006), higher 24-h urine protein excretion (7.4 vs 5.4 mg/dl (median), P=0.012), and were more often female (P=0.038). They showed more often unilateral disease (P<0.005) with larger tumors (14±10 vs 7±10 mm, P=0.021), underwent more often adrenalectomy (75% vs 37%, P<0.005), required a lower number of antihypertensive drugs after adrenalectomy (1.2±1.2 vs 2.5±1.4, P=0.001), had a faster normalization of urinary protein excretion (with medical treatment P=0.049; with Adx P<0.005) at follow-up, and more frequently underlying well-characterized mutation (P=0.047).

CONCLUSIONS

PA patients with post-SIT aldosterone levels of >100 ng/l have a more rapid development of PA caused more frequently by unilateral disease with larger aldosterone-producing adenomas. However, this group of patients may have a significantly better outcome following specific treatment.