A new highly sensitive and specific overnight combined screening and diagnostic test for primary aldosteronism

International multicenter survey on screening and confirmatory testing in primary aldosteronism

OBJECTIVE

Primary aldosteronism (PA) is one of the most frequent causes of secondary hypertension. Although clinical practice guidelines recommend a diagnostic process, details of the steps remain incompletely standardized.

DESIGN

In the present SCOT-PA survey, we have investigated the diversity of approaches utilized for each diagnostic step in different expert centers through a survey using Google questionnaires. A total of 33 centers from 3 continents participated.

RESULTS

We demonstrated a prominent diversity in the conditions of blood sampling, assay methods for aldosterone and renin, and the methods and diagnostic cutoff for screening and confirmatory tests. The most standard measures were modification of antihypertensive medication and sitting posture for blood sampling, measurement of plasma aldosterone concentration (PAC) and active renin concentration by chemiluminescence enzyme immunoassay, a combination of aldosterone-to-renin ratio with PAC as an index for screening, and saline infusion test in a seated position for confirmatory testing. The cutoff values for screening and confirmatory testing showed significant variation among centers.

CONCLUSIONS

Diversity of the diagnostic steps may lead to an inconsistent diagnosis of PA among centers and limit comparison of evidence for PA between different centers. We expect the impact of this diversity to be most prominent in patients with mild PA. The survey raises 2 issues: the need for standardization of the diagnostic process and revisiting the concept of mild PA. Further standardization of the diagnostic process/criteria will improve the quality of evidence and management of patients with PA.

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.

High Prevalence of Primary Aldosteronism in Patients with Type 2 Diabetes Mellitus and Hypertension

Primary aldosteronism (PA) is the most common cause of endocrine hypertension. The prevalence of hypertension is higher in patients with diabetes mellitus-2 (DM-2). Following the limited existing data, we prospectively investigated the prevalence of aldosterone excess either as autonomous secretion (PA) or as a hyper-response to stress in hypertensive patients with DM-2 (HDM-2). A total of 137 HDM-2 patients and 61 non-diabetics with essential hypertension who served as controls (EH-C) underwent a combined, overnight diagnostic test, the Dexamethasone–captopril–valsartan test (DCVT) used for the diagnosis of PA and an ultralow dose (0.3 μg) ACTH stimulation test to identify an exaggerated aldosterone response to ACTH stimulation. Twenty-three normotensive individuals served as controls (NC) to define the normal response of aldosterone (ALD) and aldosterone-to-renin ratio (ARR) to the ultralow dose ACTH test. Using post-DCVTALD and ARR from the EH-C, and post-ACTH peak ALD and ARR from the NC, 47 (34.3%) HDM-2 patients were found to have PA, whereas 6 (10.4%) HDM-2 patients without PA (DCVT-negative) exhibited an exaggerated aldosterone response to stress—a prevalence much higher than ever reported. Treatment with mineralocorticoid receptor antagonists (MRAs) induced a significant and permanent reduction of BP in all HDM-2 patients. Early diagnosis and targeted treatment of PA is crucial to prevent any aggravating effect on chronic diabetic complications.

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

Background:

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

Methods:

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

Results:

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

Conclusions:

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

Establishing Reference Ranges for Aldosterone, Renin and Aldosterone-to-Renin Ratio for Women in the Third-Trimester of Pregnancy

OBJECTIVE

Diagnosis of primary hyperaldosteronism in pregnancy is complicated due to lack of reference ranges for aldosterone, renin and aldosterone-to-renin ratio. We have endeavoured to establish third-trimester reference ranges for the above-mentioned parameters.

DESIGN & PATIENTS

We performed postural tests for aldosterone and renin (chemiluminescence immunoassay Liason® DiaSorin Inc., Italy) in 70 healthy pregnant women (age 30.53±4.51 years), at 32.38±4.25 weeks of gestation and in 22 non-pregnant healthy women (age 33.08±8.72 years).

RESULTS

Aldosterone reference ranges were 6.51-73.97 ng/dl and 12.33-86.38 ng/dl, for supine and upright positions, respectively and that for renin were 6.25-59.36 µIU/ml and 11.12-82.55 µIU/ml, respectively. Aldosterone and renin concentrations were higher in an upright position (p=0.000459 and p=0.00011, respectively). In contrast, aldosterone-to-renin ratio was not affected by posture (i. e. 0.497-3.084 ng/dl/µIU/ml versus 0.457-3.06 ng/dl/µIU/ml, p=0.12), but was higher (p=0.00081) than in non-pregnant controls. In comparison to manufacturer-provided non-pregnant reference range, supine aldosterone concentrations increased by 556% (lower cut-off) and 313% (upper cut-off), while upright aldosterone concentrations increased by 558% (lower cut-off) and 244% (upper cut-off). The reference range for supine renin concentrations increased by 223% (lower cut-off) and 48.7% (upper cut-off), while upright renin concentrations increased by 253% (lower cut-off) and 79% (upper cut-off).

CONCLUSIONS

There is an upward shift in aldosterone and renin reference ranges in the third-trimester of pregnancy accompanied by an increase in an aldosterone-to-renin ratio, that is not influenced by posture. It remains to be established whether the aldosterone-to-renin ratio may be used as a screening tool for primary hyperaldosteronism in pregnancy.

Primary Hyperaldosteronism: When to Suspect It and How to Confirm Its Diagnosis

The definition of primary hyperaldosteronism (PA) has shifted, as progress has been made in understanding the disease. PA can be produced by unilateral or bilateral cortical adrenal hyperproduction of aldosterone, due to hyperplasia, aldosterone-secreting cell clusters, aldosterone-producing macro or micro adenoma/s, and combinations of the above, or by an aldosterone-producing carcinoma. PA is a highly prevalent disease, affecting close to 10% of the hypertensive population. However, PA is clearly underdiagnosed. The purpose of this review is to address current knowledge of PA’s clinical manifestations, as well as current methods of diagnosis. PA is associated with a higher cardiovascular morbidity and mortality than essential hypertension with similar blood pressure control. Young hypertensive patients, those with a first-degree relative with PA or ictus, and/or those with apnea/hypopnea syndrome, moderate/severe/resistant hypertension, adrenal incidentaloma, and/or hypokalemia should be screened for PA. PA can induce atrial fibrillation (AF), and those patients should also be screened for PA. We propose the use of the Captopril challenge test (CCT), oral salt loading, or intravenous salt loading for PA diagnosis, given their availability in the majority of hospital centers. CCT could be first-line, since it is safe and easy to perform.

Hyperparathyroidism in patients with overt and mild primary aldosteronism

INTRODUCTION

Increased prevalence of hyperparathyroidism (HP) has been observed in primary aldosteronism (PA) patients. However, HP prevalence in milder forms of PA has not to date been evaluated.

OBJECTIVES

The objectives of this study were to assess the prevalence of primary and secondary HP in overt and milder misdiagnosed cases of PA and to investigate the effect of treatment on parathormone (PTH) secretion.

PATIENTS AND METHODS

Seventy PA patients with normal renal function were included prospectively. Specifically, patients with biochemically overt PA (increased basal aldosterone/renin ratio (ARR) and a positive diagnostic suppression test (DCVT)) and patients with mild PA (normal basal ARR and a positive DCVT) were analyzed. Mean blood pressure and mineral metabolism were evaluated at diagnosis and after treatment.

RESULTS

Primary and secondary HP were found in 4.3% (3/70) and 51.4% (36/70) of patients, respectively, and biochemically overt and mild PA in 47.1% (33/70) and 52.9% (37/70) of patients, respectively. Sixty-three PA patients were followed up after treatment without receiving calcium or vitamin D. There was a decrease of mean blood pressure (p < 0.001), PTH (p < 0.001), and 24-h urinary calcium (p < 0.001), and an increase of serum potassium (p < 0.001) and calcium (p = 0.018) levels in secondary HP patients. There was no significant difference between biochemically overt and mild PA patients as concerned serum PTH, calcium, and 25-hydroxyvitamin-D levels either before or after treatment. Aldosterone levels before treatment were positively correlated with serum PTH levels.

CONCLUSIONS

HP prevalence was high in both overt and mild PA patients, whereas the effect of treatment on serum and urinary calcium and PTH levels was similar in both groups.

Prevalence of Primary Aldosteronism Across the Stages of Hypertension Based on a New Combined Overnight Test

Primary aldosteronism (PA) is the most common endocrine cause of arterial hypertension. Despite the increasing incidence of hypertension worldwide, the true prevalence of PA in hypertension was only recently recognized. The objective of the work was to estimate the prevalence of PA in patients at different stages of hypertension based on a newly developed screening-diagnostic overnight test. This is a prospective study with hypertensive patients (n=265) at stage I (n=100), II (n=88), and III (n=77) of hypertension. A group of 103 patients with essential hypertension without PA was used as controls. PA diagnosis was based on a combined screening-diagnostic overnight test, the Dexamethasone-Captopril-Valsartan Test (DCVT) that evaluates aldosterone secretion after pharmaceutical blockade of angiotensin-II and adrenocorticotropic hormone. DCVT was performed in all participants independently of the basal aldosterone to renin ratio (ARR). The calculated upper normal limits for post-DCVT aldosterone levels [3 ng/dl (85 pmol/l)] and post-DCVT ARR [0.32 ng/dl/μU/ml (9 pmol/IU)] from controls, were applied together to establish PA diagnosis. Using these criteria PA was confirmed in 80 of 265 (30%) hypertensives. The prevalence of PA was: 21% (21/100) in stage I, 33% (29/88) in stage II, and 39% (30/77) in stage III. Serum K⁺ levels were negatively correlated and urinary K⁺ was positively correlated in PA patients with post-DCVT ARR (r=-0.349, p <0.01, and r=0.27, p <0.05 respectively). In conclusion, DCVT revealed that PA is a highly prevalent cause of hypertension. DCVT could be employed as a diagnostic tool in all subjects with arterial hypertension of unknown cause.

Primary Aldosteronism: a Continuum from Normotension to Hypertension

PURPOSE OF REVIEW

Primary aldosteronism (PA) is the most common cause of secondary hypertension. Emerging evidence suggests that PA is associated with cardiovascular, metabolic, and renal complications, that likely develop insidiously, due to prolonged inappropriate mineralocorticoid receptor activation. In this review, we discuss the expanding clinical and pathological spectrum of PA.

RECENT FINDINGS

Clinical and molecular studies conducted over the recent years reveal that PA traverses a series of contiguous stages. Pre-clinical, but hormonally overt PA has been identified in patients with normal blood pressure, and such patients harbor an increased risk of developing hypertension. Similarly, genetic and histopathological advancements have exposed a spectrum of PA pathology that corresponds to a continuum that spans from pre-clinical stages to florid PA. PA evolves from pre-hypertensive stages to resistant hypertension, along with serious cardiovascular and renal consequences. Early recognition of PA and targeted therapy will be essential for cardiovascular morbidity and mortality prevention in a large number of patients.

Surgical treatment outcome of primary aldosteronism assessed using new modified diagnostic tests

PURPOSE

Primary aldosteronism (PA) is the most frequent type of endocrine hypertension. In our previous studies, we introduced two modified diagnostic tests for PA, the post-dexamethasone saline infusion test (DSIT) and the overnight dexamethasone, captopril, and valsartan test (DCVT). In this study, we aimed to validate both tests in respect to the biochemical and clinical response of a cohort of hypertensive patients in pre- and post-surgical setting.

METHODS

We retrospectively studied 41 hypertensive patients (16 males), with a median (IQR, range) age of 50 (16, 35-74) years and positive histology for adrenal adenoma. Preoperatively, all patients had a single adenoma on CT and a diagnosis of PA with either DSIT or DCVT. The defined daily dose (DDD) of hypertensive drugs was assessed pre- and postoperatively. DSIT or DCVT and basal ARR were reassessed postoperatively.

RESULTS

Two of the 41 patients failed to suppress aldosterone post-surgery, leading to a post-adrenalectomy biochemical cure rate of 95%, while blood pressure was improved in 36 patients, leading to a clinical cure rate of 88% as assessed by the DDD methodology.

CONCLUSIONS

The present study was a proof-of-concept process to validate two modified diagnostic tests for PA in clinical practice. These tests, used to diagnose a group of patients with PA, successfully assessed their biochemical cure post-adrenalectomy at rates similar to those reported in the literature.

Intraindividual Variability of Aldosterone Concentrations in Primary Aldosteronism: Implications for Case Detection

Primary aldosteronism is an underdiagnosed cause of hypertension. Although inadequate screening is one reason for underdiagnosis, another important contributor is that clinicians may inappropriately exclude the diagnosis when screening aldosterone concentrations fall below traditionally established thresholds. We evaluated the intraindividual variability in screening aldosterone concentrations and aldosterone-to-renin ratios, and how this variability could impact case detection, among 51 patients with confirmed primary aldosteronism who had 2 or more screening measurements of renin and aldosterone on different days. There were a total of 137 screening measurements with a mean of 3 (range 2-6) per patient. The mean intraindividual variability, expressed as coefficients of variation, was 31% for aldosterone and 45% for the aldosterone-to-renin ratio. Aldosterone concentrations ranged from 4.9 to 51 ng/dL; 49% of patients had at least one aldosterone measurement below 15 ng/dL, 29% had at least 2 aldosterone measurements below 15 ng/dL, and 29% had at least one measurement below 10 ng/dL. Individual aldosterone-to-renin ratios ranged from 8.2 to 427 ng/dL per ng/mL·hour; 57% had at least one ratio below 30 ng/dL per ng/mL·hour, 27% had at least 2 ratios below 30 ng/dL per ng/mL·hour, and 24% had at least one ratio below 20 ng/dL per ng/mL·hour. Aldosterone concentrations and aldosterone-to-renin ratios are highly variable in patients with primary aldosteronism, with many screening values falling below conventionally accepted diagnostic thresholds. The diagnostic yield for primary aldosteronism may be substantially increased by recalibrating the definition of a positive screen to include more liberal thresholds for aldosterone and the aldosterone-to-renin ratio.

Five Reasons for the Failure to Diagnose Aldosterone Excess in Hypertension

Primary hyperaldosteronism (PA) is a well-known cause of hypertension although its exact prevalence amongst patients with apparent essential hypertension has been a matter of debate. A number of recent studies have suggested that mild forms of PA may be relatively common taking into consideration factors that were previously either overestimated or ignored when developing diagnostic tests of PA and when applying these tests into normotensive individuals. The performance characteristics and diagnostic accuracy of such tests are substantially increased when the adrenocorticotrophin effect, inappropriate potassium levels and their application in carefully selected normotensive individuals are considered. In the present review, we critically analyze these issues and provide evidence that several, particularly mild, forms of PA can be effectively identified exhibiting potentially important clinical implications.

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.

Criteria for diagnosing primary aldosteronism on the basis of liquid chromatography-tandem mass spectrometry determinations of plasma aldosterone concentration

BACKGROUND

Primary aldosteronism is affecting about 10% of hypertensive patients. Primary aldosteronism should be diagnosed by screening tests based on plasma aldosterone concentration (PAC) and aldosterone-to-renin ratio (ARR), followed by confirmatory test. The cutoff values for PAC and ARR depend on PAC and plasma renin measurement methods. Liquid chromatography-tandem mass spectrometry (LC-MS/MS), the new gold standard method for aldosterone determination, is now widespread but shows lower values than immunoassays. New cutoff values have yet to be determined with LC-MS/MS PAC.

METHODS

In a retrospective cohort, we measured PAC by LC-MS/MS in 93 healthy volunteers, 77 patients with essential hypertension and 82 primary aldosteronism patients (42 lateralized, 24 bilateral, 16 primary aldosteronism without adrenal vein sampling) after 30 min in a seated position.

RESULTS

PAC ranged from 42 to 309 pmol/l in healthy volunteers and from 63 to 362 pmol/l in essential hypertensive patients. A cutoff value of 360 pmol/l for basal PAC had a sensitivity of 90.5% and a specificity of 95.1% to differentiate lateralized primary aldosteronism from essential hypertensive patients. ARR ranged from 2.3 to 22.3 in healthy volunteers and from 3.2 to 55.6 pmol/mU in essential hypertensive patients. Using ROC curves, we selected an ARR of 46 pmol/mU, which provided a sensitivity of 100% and a specificity of 93.4% to distinguish between essential hypertensive and lateralized primary aldosteronism patients (sensitivity 94.4%, specificity 93.9% for the overall primary aldosteronism population).

CONCLUSION

Criteria for primary aldosteronism screening need to be adapted, given the increasing use of LC-MS/MS to determine PAC. We suggest to use 360 pmol/l and 46 pmol/mU as cutoff values, respectively, for basal PAC and ARR after 30 min of seated rest.

Confirmatory tests for the diagnosis of primary aldosteronism: A systematic review and meta-analysis

OBJECTIVE

Saline infusion test (SIT), captopril challenge test (CCT), fludrocortisone suppression test (FST) and oral sodium loading test (SLT) are recommended by the Endocrine Society's Clinical Practice Guidelines to diagnose primary aldosteronism, but which one is the best remains controversial. We aimed to summarize the available comparative data and evaluate the diagnostic accuracy of these four tests.

DESIGN

We searched PubMed, Embase and the Cochrane Library for relevant studies published between January 1980 and January 2018.

PATIENTS

Eligible studies reported on the accuracy of one or more of the four confirmatory tests in patients suspected of PA.

MEASUREMENTS

Two reviewers independently conducted the data extraction of all selected studies, which consisted of study characteristics and data to estimate the summary receiver operating characteristic (SROC) curve and the corresponding summary area under the curve (SAUC), pooled sensitivity and specificity, diagnostic odds ratios (DOR) with 95% confidence interval (CI).

RESULTS

We identified 26 articles including 3686 patients. Fifteen articles evaluated the diagnostic accuracy of CCT, 10 of SIT, 1 of FST and none of SLT. For CCT, the SAUC was 0.9207, and the pooled sensitivity and specificity were 0.87 (95% CI: 0.84-0.89) and 0.84 (95% CI: 0.81-0.86), respectively. For SIT, the SAUC was 0.9232, and the pooled sensitivity and specificity were 0.85 (95% CI: 0.82-0.87) and 0.87 (95% CI: 0.85-0.89), respectively. For FST, the pooled sensitivity and specificity were 0.87 (95% CI: 0.66-0.97) and 0.95 (95% CI: 0.82-0.99), respectively. Overall, we found no significant differences in the diagnostic accuracy of CCT and SIT.

CONCLUSIONS

CCT and SIT exhibit high and comparable accuracy for diagnosing PA. CCT may be a more feasible alternative as it is safe and much easier to perform.

Adrenocortical incidentalomas and bone: from molecular insights to clinical perspectives

Adrenal incidentalomas constitute a common clinical problem with an overall prevalence of around 2-3%, but are more common with advancing age being present in 10% of those aged 70 years. The majority of these lesions are benign adrenocortical adenomas (80%), characterized in 10-40% of the cases by autonomous cortisol hypersecretion, and in 1-10% by aldosterone hypersecretion. Several observational studies have shown that autonomous cortisol and aldosterone hypersecretion are more prevalent than expected in patients with osteopenia and osteoporosis: these patients have accelerated bone loss and an increased incidence of vertebral fractures. In contrast to glucocorticoid action, the effects of aldosterone on bone are less well understood. Recent data, demonstrating a concomitant co-secretion of glucocorticoid metabolites in patients with primary aldosteronism, could explain some of the metabolic abnormalities seen in patients with aldosterone hypersecretion. In clinical practice, patients with unexplained osteoporosis, particularly when associated with other features such as impaired glucose tolerance or hypertension, should be investigated for the possible presence of autonomous cortisol or aldosterone secretion due to an adrenal adenoma. Randomized intervention studies are needed, however, to investigate the optimum interventions for osteoporosis and other co-morbidities in these patients.