PREVELENCE OF PRIMARY ALDOSTERONISM IN AN URBAN HYPERTENSIVE POPULATION

Endocrine Hypertension: The Urgent Need for Greater Global Awareness

Hypertension affects about 1.28 billion adults globally, and significantly increases the risk of chronic morbidity and mortality among sufferers. About 15% of these individuals have secondary hypertension, the majority of whom have dysfunction of one or more endocrine systems as the cause of hypertension. Although adrenal disorders are often identified as the cause of endocrine hypertension, extra-adrenal disease and pituitary disorders also can cause the disease. Timely diagnosis is of paramount importance, because of the potential for a surgical cure or optimal disease control with pharmacotherapy to prevent hypertensive complications. Even with its relatively high prevalence compared with many other chronic illnesses, the diagnosis of endocrine hypertension is often delayed or never made because of poor awareness about the disease among physicians. This review attempts to provide an overview of the disease, with some practical aspects of diagnosis and management of a few of the important disorders causing endocrine hypertension.

Primary Aldosteronism Prevalence - An Unfolding Story

Primary aldosteronism (PA) is characterized by dysregulated, renin-independent aldosterone excess. Long perceived as rare, PA has emerged as one of the most common causes of secondary hypertension. Failure to recognize and treat PA results in cardiovascular and renal complications, through processes mediated by both direct target tissue insults and indirectly, by hypertension. PA spans a continuum of dysregulated aldosterone secretion, which is typically recognized in late stages after treatment-resistant hypertension and cardiovascular and/or renal complications develop. Determining the precise disease burden remains challenging due to heterogeneity in testing, arbitrary thresholds, and populations studied. This review summarizes the reports on PA prevalence among the general population and in specific high-risk subgroups, highlighting the impact of rigid versus permissive criteria on PA prevalence perception.

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.

Primary Aldosteronism: State-of-the-Art Review

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

Primary aldosteronism - a multidimensional syndrome

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

Performance of 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.

Recent Development toward the Next Clinical Practice of Primary Aldosteronism: A Literature Review

For the last seven decades, primary aldosteronism (PA) has been gradually recognized as a leading cause of secondary hypertension harboring increased risks of cardiovascular incidents compared to essential hypertension. Clinically, PA consists of two major subtypes, surgically curable and uncurable phenotypes, determined as unilateral or bilateral PA by adrenal venous sampling. In order to further optimize the treatment, surgery or medications, diagnostic procedures from screening to subtype differentiation is indispensable, while in the general clinical practice, the work-up rate is extremely low even in the patients with refractory hypertension because of the time-consuming and labor-intensive nature of the procedures. Therefore, a novel tool to simplify the diagnostic flow has been recently in enormous demand. In this review, we focus on recent progress in the following clinically important topics of PA: prevalence of PA and its subtypes, newly revealed histopathological classification of aldosterone-producing lesions, novel diagnostic biomarkers and prediction scores. More effective strategy to diagnose PA based on better understanding of its epidemiology and pathology should lead to early detection of PA and could decrease the cardiovascular and renal complications of the patients.

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.

Prevalence, diagnosis and outcomes of treatment for primary aldosteronism

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