Is it time to screen all patients with hypertension for primary aldosteronism?

Temporal trends in clinical features of patients with primary aldosteronism over 20 years

Primary aldosteronism (PA) accounts for approximately 5-10% of hypertension cases. Over the past 20 years, the reported incidence of PA has increased due to widespread screening for secondary hypertension and imaging studies. We aimed to evaluate the temporal trends in the clinical characteristics and subtypes of PA. A total of 1064 patients with PA in two tertiary hospitals between 2000 and 2021 were categorized into three groups according to the year of diagnosis: 2000-2009, 2010-2015, and 2016-2021. The clinical characteristics of the patients over the three time periods were compared using a trend analysis. The age at diagnosis and sex of patients with PA did not change over 20 years. The proportion of patients with bilateral hyperaldosteronism (BHA) increased (11%, 25%, and 40%, P for trend <0.001). The proportion of hypokalemia (87%, 61%, and 40%) and plasma aldosterone concentration (36.0, 30.8, and 26.6 ng/dL) decreased (all P for trend <0.001). There was a trend toward an increased proportion of incidentally detected patients compared to clinically symptomatic patients (36%, 55%, and 61%, P for trend <0.001). The concordance rate of imaging and adrenal venous sampling results decreased (91%, 70%, and 57% P for trend <0.001). However, the proportion of patients with resistant hypertension and comorbidities did not differ. In conclusion, among patients with PA, patients with BHA and incidental detection have increased over 20 years, and more patients are likely to present with milder clinical symptoms and biochemical profiles.

Screening for primary aldosteronism in primary care: a scoping review

BACKGROUND

Primary aldosteronism (PA) is the most common treatable and potentially curable cause of secondary hypertension. Prompt diagnosis and management by primary care physicians (PCPs) is important given the increased risk of cardiovascular complications however screening rates are low in primary care. Our aim was to identify factors that influence screening behaviour for PA among PCPs.

METHOD

A rigorous scoping review of seven databases between 16/08/22 and 09/08/23 was used to investigate PA screening practices. Articles written in English from peer-reviewed literature within the last 20 years were eligible for inclusion if an aspect of their study was conducted in primary care.

RESULTS

A total of 1380 titles and abstracts, and 61 full texts were screened, with 20 studies selected for data extraction. We identified three broad categories of factors influencing screening by PCPs-the patient, the clinician, and the healthcare system. Some studies targeted these factors to improve screening rates although there is little data on implementation and outcomes.

CONCLUSION

Low awareness, inadequate guidelines, and poor access to testing were identified as key barriers to PA screening. Targeted education sessions for PCPs, clear guidelines, and closer proximity to diagnostic centres may be required to improve PA detection in primary care.

Hypertension in the emergency department: A missed opportunity to screen for primary aldosteronism?

OBJECTIVES

Primary aldosteronism (PA) is a common but underdiagnosed secondary cause of hypertension. Emergency departments (EDs) often assess patients with severe hypertension or its sequelae, some of whom have underlying PA. We aimed to determine the proportion of patients presenting to the ED with hypertension who meet the Endocrine Society criteria for PA testing and the proportion who were screened.

METHODS

We performed a structured retrospective chart review of adults who presented to three EDs in an Australian tertiary health network between August 2019 and February 2020, with a coded presenting complaint of hypertension. Clinical parameters to determine whether the patients met the criteria for PA testing were extracted from electronic medical records.

RESULTS

Of the 418 patients who presented to the EDs with documented elevated blood pressure (BP), 181 patients (43.3%) fulfilled PA screening criteria and nine patients (2.2%) underwent PA testing. Individuals who fulfilled screening criteria were older; had higher prevalence of Type 2 diabetes, coronary artery disease, and congestive heart failure; took more antihypertensive medications; and had lower estimated glomerular filtration rate. Individuals who were tested for PA were younger and had higher BP on presentation. Screening for PA was more frequent in patients who were referred to medical teams.

CONCLUSIONS

As far as we are aware, our study is the first to evaluate PA testing in hypertensive patients who present to ED. More than 40% of adults presenting to the EDs with hypertension met the current criteria for testing for PA but only few were tested. These results emphasize that increased awareness of PA in the ED is needed to encourage opportunistic testing, referral, and treatment, especially in patients who present with hypertensive emergencies. Prospective studies are required to determine the feasibility and effectiveness of this.

The where, who and how of adrenal vein sampling in Australia and New Zealand

INTRODUCTION

Primary aldosteronism (PA) causes 10-15% of cases of hypertension, and it is increasingly recognised as being under-diagnosed. An interventional radiology procedure, adrenal vein sampling (AVS), is a necessary and important diagnostic procedure for complete workup of PA. There is an anticipated increase in demand for AVS as detection of PA improves. This study aims to describe the current landscape of AVS in Australia and New Zealand (NZ).

METHODS

Two surveys exploring AVS methodology and performance were conducted of (i) Endocrinology Unit Heads and (ii) interventional radiologists who perform AVS, at public hospitals with Endocrinology Units across Australia and NZ.

RESULTS

Responses were received from 48/53 Endocrinology Unit Heads (91%) and 35 radiologists from 26 sites (87% of AVS sites). AVS was provided at 28/48 Endocrinology sites (58%) across Australia and NZ. In Australia, sites were concentrated in Victoria, New South Wales and Queensland with none in the Northern Territory; in NZ, sites were more evenly distributed across the North and South Islands. AVS was performed by 1-2 dedicated radiologists at 24 sites, 2-3 radiologists at two sites and a rotating roster of radiologists at two sites. Responses to both surveys revealed significant variation in AVS methodology and interpretation of AVS results.

CONCLUSION

There is significant heterogeneity in the availability of AVS, the procedural details and the interpretation of results across Australia and NZ, which potentially impacts the quality of patient care and ability to scale up AVS capacity to meet increasing demand.

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.

Improving Detection Rates for Primary Aldosteronism

Primary aldosteronism (PA), once considered a rare disease, is being increasingly recognized as an important cause of hypertension. It is associated with higher rates of cardiovascular complications compared to blood pressure-matched essential hypertension. Targeted treatments are available which can mitigate the excess cardiovascular risks and, in some cases, cure hypertension. Making a timely diagnosis of PA is, therefore, highly beneficial for patients. Furthermore, numerous studies from different parts of the world have found PA to be a relatively common disease that can affect patients in any stage of hypertension, regardless of their age or potassium levels. Despite this well-established data, the current rate of PA detection is appallingly low, much below its actual prevalence. This review explores the challenges that clinicians often face in diagnosing PA and offers strategies that may improve the detection of this potentially curable form of hypertension.

The adrenal vein sampling outcomes study (AVOS): success rates following adrenalectomy for unilateral primary aldosteronism

The objective was to determine the clinical and biochemical success rates and assess the nature of follow-up after adrenalectomy in patients with unilateral primary aldosteronism (PA), subtyped by adrenal vein sampling (AVS) in West Australia (WA) using the Primary Aldosteronism Surgical Outcome (PASO) criteria. Clinical and biochemical outcomes were retrospectively evaluated in patients with unilateral PA who underwent adrenalectomy according to AVS between September 2017 and September 2020. Pre- and post-surgical data were collected using a standardised questionnaire, review of clinic letters and examination of private and public pathology results and radiological reports. Follow-up data were available for 47 patients post-adrenalectomy; biochemical outcome data were available for 37 patients, clinical outcome data for 40 patients, with 30 patients having both outcomes available. Final assessment was performed between 0 to 3 months in 23/37 (62.2%) patients with biochemical outcomes, 15/40 (37.5%) with clinical outcomes, and 17/30 (56.7%) with both clinical and biochemical outcomes. Complete biochemical success was achieved in 83.8% (31/37) of patients, with 26.7% (8/30) obtaining both complete clinical and biochemical success. Complete clinical success was achieved in 35.0% (14/40) of patients, with 47.5% (19/40) obtaining partial clinical success. Overall, 93.6% (44/47) of patients derived benefit from adrenalectomy. The outcomes of adrenalectomy for unilateral PA in Western Australian using standardised PASO criteria demonstrate highly comparable clinical and biochemical success rates to international data. However, further standardisation of post-operative follow-up care needs to be implemented to ensure the recommended repeat follow-up assessment criteria are collected.

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.

'I can't understand why others don't screen more': a qualitative study exploring why Australian general practitioners screen for primary aldosteronism

OBJECTIVE

We sought to understand the factors that influence a general practitioner's (GP's) experience of screening for primary aldosteronism (PA) in hypertensive patients.

DESIGN

A qualitative study, framed by phenomenology, using semistructured interviews that were audiorecorded, transcribed verbatim, entered into NVivo V.12.0 for coding and analysed for emerging themes.

SETTING

Melbourne, Australia.

PARTICIPANTS

Eligible GPs had received education on PA as part of a previous study. We recruited a purposive sample of 16 GPs (6 females, 10 males) who varied in practice location, clinical experience and the number of patients screened for PA.

RESULTS

Although GPs had been educated about PA, they found it challenging to explain the condition to patients and were uncertain about how to screen patients who were already taking antihypertensive medications. Most viewed the screening process to be practical, inexpensive and, by and large, acceptable to their patients. However, they found it inconvenient to alter antihypertensive medications before screening to allow for easier interpretation of the aldosterone-renin ratio. They were also less enthused about screening patients whom they thought fitted a clinical picture of essential hypertension. Knowledge of the screening process, cost and convenience of performing the aldosterone-renin ratio, conceptualisation of risk related to PA, and a desire to improve clinical care were influencing factors that modified the GPs' screening experience.

CONCLUSION

Our findings suggest that knowledge gaps, practical limitations of the aldosterone-renin ratio, and errors in diagnostic reasoning were challenges of routine PA screening. Most of these practical barriers could be addressed by relatively simple educational and practice modifications to increase PA screening rates and optimise detection for the most common cause of secondary hypertension in primary care.

Performance of the aldosterone-to-renin ratio as a screening test for primary aldosteronism in primary care

Primary aldosteronism (PA) is the most common and potentially curable form of secondary hypertension, affecting 5-10% of primary care patients with hypertension. Primary care physicians have an important role in initiating the screening for PA in patients with hypertension and referring to a specialist service depending on the screening test results. The currently recommended screening test for PA is the plasma aldosterone-to-renin ratio (ARR). Test results are influenced by medications so careful patient preparation is required including adjusting existing antihypertensive medications to avoid diagnostic errors. A range of laboratory method-dependent ARR thresholds are used for the screening of PA around the world. Periodic clinical audits and case reviews by clinicians and the laboratory may help refine the local thresholds. Patients with an abnormally elevated ARR should be referred to a specialist for confirmatory testing while patients with a high pre-test probability but a normal ARR could have a repeat test in view of the within-individual variability. Despite the heterogenous ARR thresholds, measuring the ARR is still more likely to detect PA than not screening at all.

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.

Screening for Primary Aldosteronism in the Diabetic Population: a cohort study

CONTEXT

Primary aldosteronism (PA) is the most common endocrine cause of hypertension. It is associated with higher cardio-metabolic risk than essential hypertension. Hypertension is common in patients with type 2 diabetes who carry increased cardiovascular risk, however, it is unknown how frequently they are tested for PA.

OBJECTIVE

The study aims to assess the extent to which the Endocrine Society's 2016 PA screening guidelines have been applied in a tertiary diabetes care setting and evaluate the demographic, clinical and biochemical characteristics of patients who met screening criteria compared to those who did not.

RESEARCH DESIGN & METHODS

This is a retrospective cohort study. Data were collected from 272 patients who attended tertiary Diabetes Clinics and had two or more blood pressure measurements from January to December 2018.

RESULTS

Of 272 patients, 63 (23.2%) had indication(s) for PA screening but only 15 (23.8% of 63) were screened using the aldosterone-to-renin ratio (ARR). Four patients who did not meet screening criteria were screened. Only one of 19 patients screened had an abnormal ARR, however 16 were taking medications known to affect aldosterone and/or renin production.

CONCLUSIONS

In a tertiary diabetes outpatient setting, only a minority of patients who fulfilled the Endocrine Society criteria for PA screening were actually screened. Appropriate screening for PA in the diabetic hypertensive population is necessary for the diagnosis and targeted treatment of a highly modifiable cardiovascular risk factor. Further studies are needed to develop feasible strategies to identify patients with PA in this population. This article is protected by copyright. All rights reserved.

Hypertension Management in Stroke Prevention: Time to Consider Primary Aldosteronism

Primary aldosteronism confers a higher risk of stroke, atrial fibrillation, and cardiovascular disease than blood pressure matched essential hypertension. It is the most common endocrine cause of secondary hypertension with prevalence estimates of up to 13% in primary care and 30% in referral centers around the world. Unlike essential hypertension, primary aldosteronism has targeted medical treatment and potentially curative surgical solutions which can ameliorate the associated cardiovascular risks. This narrative review highlights an evidence gap in the optimal diagnosis and targeted treatment of primary aldosteronism in secondary stroke prevention. Over half of the patients suffering a stroke have blood pressure in the hypertensive range and less than a third achieve optimal blood pressure control. There are no guideline recommendations to test for primary aldosteronism in these patients, although up to 30% of patients with resistant hypertension may have this disease. The accurate diagnosis of primary aldosteronism could significantly improve blood pressure, simplify the medication regimen and reduce the overall cardiovascular risk in these patients. The challenges associated with screening for primary aldosteronism following stroke may be overcome by novel blood tests which are less affected by antihypertensive medications routinely used in stroke care. Approximately one-quarter of all strokes occur in patients who have previously had a stroke. Modifying hypertension, the leading modifiable risk factor, would, therefore, have significant public health implications. As clinicians, we must increase our awareness of primary aldosteronism in patients with stroke, particularly in those with resistant hypertension, to enable targeted therapy and reduce the risk of stroke recurrence.

An LC-MS/MS assay for analysis of equilibrium angiotensin II in human serum

BACKGROUND

The current first-line screening test for primary hyperaldosteronism is the plasma aldosterone:renin ratio; however, renin assays have several disadvantages and the ARR is affected by medications and physiological factors. Angiotensin II is a key biologically active hormone in the renin-angiotensin-aldosterone system. It has been suggested that measurement of equilibrium levels of this peptide, involving an in vitro incubation of serum prior to analysis, may provide a better marker of renin-angiotensin-aldosterone system activity than renin.

METHODS

An eqAng II LC-MS/MS assay was developed, optimized and validated. Serum samples were incubated at 37°C for 45 min prior to stabilization with cold EDTA solution, solid phase extraction and LC-MS/MS analysis. Stability in whole blood and the effect of cryoactivation were assessed. For comparison to the current screening test, 150 anonymized patients' samples were analysed for eqAng II, renin activity and aldosterone (all by LC-MS/MS).

RESULTS

The assay had good precision, minimal bias and acceptable recovery. EqAng II did not change significantly when whole blood samples were stored for up to 72 h, and cryoactivation was only observed for pregnant patients. EqAng II was significantly correlated with renin, and the aldosterone:eqAng II ratio had a strong positive correlation with the aldosterone:renin ratio.

CONCLUSIONS

An LC-MS/MS assay for eqAng II has been developed which shows promise as an alternative screening test for primary hyperaldosteronism. Compared to renin assays, it is quicker, simpler and less likely to be affected by anti-hypertensive medications. Further clinical validation in hypertensive patients would be required prior to implementation.

Comparison of ambulatory blood pressure between patients with primary aldosteronism and other forms of hypertension

OBJECTIVE

Primary aldosteronism (PA) is a potentially curable cause of hypertension associated with worse cardiovascular prognosis than blood pressure-matched essential hypertension (EH). Effective targeted treatment for PA is available with the greatest benefit seen if treatment is started early, prior to the development of end-organ damage. However, PA is currently substantially under-diagnosed. The standard screening test for PA, the aldosterone-to-renin ratio (ARR), is performed infrequently in both primary and tertiary care. In contrast, ambulatory blood pressure monitoring (ABPM) is frequently utilized in the assessment of hypertension. The aim of this study was to compare ABPM parameters in hypertensive patients with and without PA, in order to identify features of ABPM associated with PA that can prompt screening.

STUDY DESIGN

Patients with PA (n = 55) were identified from a tertiary clinic specializing in the management of endocrine causes of hypertension whilst the controls (n = 389) were consecutive patients with hypertension but without a known diagnosis of PA who were referred for ABPM.

RESULTS

In this study, PA patients were younger and had higher 24-h, day, and night-time blood pressure compared with controls despite similar number of antihypertensive medications. However, there was no significant difference in nocturnal dipping or day-night blood pressure variability between the two groups.

CONCLUSIONS

An elevated ambulatory blood pressure in patients on multiple antihypertensives could suggest underlying PA but in the absence of other distinguishing features, ABPM could not reliably differentiate PA from other forms of hypertension. Routine biochemical screening for PA remained the most reliable way of detecting this treatable secondary cause of hypertension.

Primary aldosteronism is a public health issue: challenges and opportunities

A significant proportion of hypertension (potentially more than 5% in the general population) is due to primary aldosteronism (PA) which carries a worse prognosis when compared with blood pressure-matched essential hypertension. Effective targeted treatments are available which mitigate many of the cardiovascular complications of untreated PA. Despite this, the detection rate of PA in primary care is sub-optimal. In this review, we explore the challenges contributing to the under-diagnosis of PA in the community, including uncertainties regarding its actual prevalence. In order to detect PA early and offer targeted treatment before adverse cardiovascular consequences develop, routine screening for PA at the time of a diagnosis of hypertension would seem desirable. However, this is limited by a lack of studies to establish whether routine screening in primary care is cost-effective. Newer techniques are also being developed which could lessen the complexity of diagnosing PA. Most importantly, a dramatic increase in awareness of PA, as a treatable cause of hypertension, is needed amongst clinicians who manage hypertension.