Recalibrating Interpretations of Aldosterone Assays Across the Physiologic Range: Immunoassay and Liquid Chromatography-Tandem Mass Spectrometry Measurements Under Multiple Controlled Conditions.

Context: Clinicians frequently rely on aldosterone thresholds derived from older immunoassays to diagnose primary aldosteronism. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is increasingly widespread and reported to yield lower aldosterone concentrations. Objective: Given the health impact of incorrect interpretations of aldosterone levels, we compared measurements using LC-MS/MS and immunoassay across the full range of aldosterone physiology by evaluating distinct regulation by angiotensin II and adrenocorticotropin (ACTH). Methods: Normotensive volunteers underwent prospective characterization of aldosterone production by immunoassay and LC-MS/MS during 4 conditions (n = 188): oral sodium suppression and restriction (to assess angiotensin II-mediated aldosterone production) and dexamethasone suppression and cosyntropin stimulation (to assess ACTH-mediated aldosterone production). Results: Serum aldosterone concentrations by LC-MS/MS and immunoassay had a correlation of 0.69 (P < .001), with good agreement (intraclass correlation 0.76; 95% CI 0.52-0.87). Aldosterone was lower by LC-MS/MS than immunoassay (median 10.5 [3.8, 21.9] vs 19.6 [9.5, 28.0] ng/dL; P < .001), with an average difference of 37.2%. The most notable discrepancy was in the clinically discriminatory range <20 ng/dL: 9.9 (7.1, 13.8) ng/dL using immunoassay corresponded to 5.5 (1.4, 8.9) ng/dL by LC-MS/MS (P < .001). Following oral sodium suppression, the aldosterone-to-renin ratio was 4-fold higher using immunoassay (27.2 [19.7, 62.4] vs 6.4 [3.5, 19.1] ng/dL per ng/mL/hour; P < .001). Conclusion: Aldosterone measurements are substantially lower by LC-MS/MS than immunoassay across the full physiologic range, especially when aldosterone levels were less than 20 ng/dL. These findings highlight the need to recalibrate diagnostic interpretations when measuring aldosterone via LC-MS/MS and provide insights into potential biologic causes of assay differences.

Screening Rates for Primary Aldosteronism Among Individuals With Hypertension Plus Hypokalemia: A Population-Based Retrospective Cohort Study.

Primary aldosteronism is a common, yet highly underdiagnosed, cause of hypertension that leads to disproportionately high rates of cardiovascular disease. Hypertension plus hypokalemia is a guideline-recommended indication to screen for primary aldosteronism, yet the uptake of this recommendation at the population level remains unknown. We performed a population-based retrospective cohort study of adults ≥18 years old in Ontario, Canada, with hypertension plus hypokalemia (potassium <3.5 mEq/L) from 2009 to 2015 with follow-up through 2017. We measured the proportion of individuals who underwent primary aldosteronism screening via the aldosterone-to-renin ratio based upon hypokalemia frequency and severity along with concurrent antihypertensive medication use. We assessed clinical predictors associated with screening via Cox regression. The cohort included 26 533 adults of which only 422 (1.6%) underwent primary aldosteronism screening. When assessed by number of instances of hypokalemia over a 2-year time window, the proportion of eligible patients who were screened increased only modestly from 1.0% (158/15 983) with one instance to 4.8% (71/1494) with ≥5 instances. Among individuals with severe hypokalemia (potassium <3.0 mEq/L), only 3.9% (58/1422) were screened. Among older adults prescribed ≥4 antihypertensive medications, only 1.0% were screened. Subspecialty care with endocrinology (hazard ratio [HR], 1.52 [95% CI, 1.10-2.09]), nephrology (HR, 1.43 [95% CI, 1.07-1.91]), and cardiology (HR, 1.39 [95% CI, 1.14-1.70]) were associated with an increased likelihood of screening, whereas age (HR, 0.95 [95% CI, 0.94-0.96]) and diabetes (HR, 0.66 [95% CI, 0.50-0.89]) were inversely associated with screening. In conclusion, population-level uptake of guideline recommendations for primary aldosteronism screening is exceedingly low. Increased education and awareness are critical to bridge this gap.

Morphologically Normal-Appearing Adrenal Glands as a Prevalent Source of Aldosterone Production in Primary Aldosteronism.

BACKGROUND: Normal-appearing adrenal glands on cross-sectional imaging may still be the source of aldosterone production in primary aldosteronism (PA). METHODS: We evaluated the prevalence of aldosterone production among morphologically normal-appearing adrenal glands and the impact of this phenomenon on interpretations of localization studies and treatment decisions. We performed a retrospective cohort study of PA patients with at least 1 normal adrenal gland and reanalyzed contemporary studies to assess interpretations of imaging and adrenal venous sampling (AVS) at the individual patient and adrenal levels. RESULTS: Among 243 patients, 43 (18%) had bilateral normal-appearing adrenals and 200 (82%) had a unilateral normal-appearing adrenal, for a total of 286 normal-appearing adrenal glands. 38% of these normal-appearing adrenal glands were a source of aldosteronism on AVS, resulting in discordance between imaging and AVS findings in 31% of patients. Most patients with lateralizing PA underwent curative unilateral treatment (80%); however, curative treatment was pursued in 92% of patients who had concordant imaging-AVS results but in only 38% who had discordant results (P < 0.05). In young patients, imaging-AVS discordance was detected in 32% of those under 45 years and 21% of those under 35 years. Among 20 contemporary studies (including 4,904 patients and 6,934 normal-appearing adrenal glands), up to 64% of normal-appearing adrenals were a source of aldosteronism resulting in 31% of patients having discordant results. CONCLUSIONS: Morphologically normal-appearing adrenal glands are commonly the source of aldosterone production in PA, even among young patients. The lack of awareness of this issue may result in inappropriate treatment recommendations.

Adrenocorticotropic Hormone-Stimulated Adrenal Venous Sampling Underestimates Surgically Curable Primary Aldosteronism: A Retrospective Cohort Study and Review of Contemporary Studies.

[Figure: see text].

Assessment of mild autonomous cortisol secretion among incidentally discovered adrenal masses.

Incidentally discovered adrenal masses are common and mostly benign and non-functioning adenomas. However, evolving evidence suggests that a notable proportion of these adrenal adenomas may demonstrate mild autonomous cortisol secretion (MACS), which has been associated with an increased risk for hypertension, hyperglycemia, obesity, dyslipidemia, vertebral fractures, adverse cardiovascular events, and mortality. Therefore, it is advised that all patients with an incidentally discovered adrenal mass be tested for MACS. When there is convincing evidence for MACS, surgical adrenalectomy has been associated with an improvement in certain metabolic parameters and a reduction in vertebral fractures; however, conclusive evidence demonstrating decreased cardiovascular outcomes or mortality are not yet available. Future studies with adequate randomization and follow-up to assess adverse clinical endpoints are needed to determine the optimal management and follow-up of patients with MACS.

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.

Variability of Aldosterone Measurements During Adrenal Venous Sampling for Primary Aldosteronism.

BACKGROUND: Variability of aldosterone concentrations has been described in patients with primary aldosteronism. METHODS: We performed a retrospective cohort study of 340 patients with primary aldosteronism who underwent adrenal venous sampling (AVS) at a tertiary referral center, 116 of whom also had a peripheral venous aldosterone measured hours before the procedure. AVS was performed by the same interventional radiologist using bilateral, simultaneous sampling, under unstimulated and then stimulated conditions, and each sample was obtained in triplicate. Main outcome measures were: (i) change in day of AVS venous aldosterone from pre-AVS to intra-AVS and (ii) variability of triplicate adrenal venous aldosterone concentrations during AVS. RESULTS: Within an average duration of 131 minutes, 81% of patients had a decline in circulating aldosterone concentrations (relative decrease of 51% and median decrease of 7.0 ng/dl). More than a quarter (26%) of all patients had an inferior vena cava aldosterone of ≤5 ng/dl at AVS initiation. The mean coefficient of variation of triplicate adrenal aldosterone concentrations was 30% and 39%, in the left and right veins, respectively (corresponding to a percentage difference of 57% and 73%), resulting in lateralization discordance in up to 17% of patients if the lateralization index were calculated using only one unstimulated aldosterone-to-cortisol ratio rather than the average of triplicate measures. CONCLUSIONS: Circulating aldosterone levels can reach nadirs conventionally considered incompatible with the primary aldosteronism diagnosis, and adrenal venous aldosterone concentrations exhibit acute variability that can confound AVS interpretation. A single venous aldosterone measurement lacks precision and reproducibility in primary aldosteronism.

The Prevalence of Primary Aldosteronism and Evolving Approaches for Treatment.

Over six decades since primary aldosteronism was first described, much has been learned about its prevalence and optimal treatment. Estimates of the prevalence of primary aldosteronism have increased considerably over the years, even exceeding 20% in some populations of resistant hypertension. Even in patients with normal blood pressures, the prevalence of overt primary aldosteronism and dysregulated aldosterone production may be more common than appreciated. Emerging data support the concept that primary aldosteronism may be better characterized as a continuum of renin-independent aldosterone production, whose severity influences the clinical presentation and risk for incident cardiovascular disease. Mineralocorticoid receptor antagonists and adrenalectomy are the mainstay treatments for primary aldosteronism and have long been considered equally efficacious. However, recent data suggest that while surgical adrenalectomy can effectively reduce cardiovascular risk, mineralocorticoid receptor antagonist therapy may require a physiologic approach to optimize efficacy.

Incidence of Atrial Fibrillation and Mineralocorticoid Receptor Activity in Patients With Medically and Surgically Treated Primary Aldosteronism.

Importance: Primary aldosteronism (PA) is an ideal condition to evaluate the role of the mineralocorticoid receptor (MR) in the pathogenesis of atrial fibrillation (AF). Objective: To investigate whether MR antagonist therapy or surgical adrenalectomy in PA influence the risk for incident AF. Design: This cohort study included patients aged 18 years and older. Patients with PA and age-matched patients with essential hypertension were identified via electronic health records. Patients with a history of AF, myocardial infarction, congestive heart failure, or stroke were excluded. Data were collected between 1991 and the end of 2016 in an academic medical center, with a mean follow-up duration of approximately 8 years. Exposures: Patients with PA treated with MR antagonists or surgical adrenalectomy were compared with patients with essential hypertension. Patients with PA who were treated with MR antagonists were categorized by whether their plasma renin activity remained suppressed (< 1 ng/mL/h) or substantially increased (≥ 1 ng/mL/h), as proxies for insufficient or sufficient MR blockade. Main Outcomes and Measure: Incident AF. Results: A total of 195 patients with PA who were treated with MR antagonists and 201 patients with PA treated with surgical adrenalectomy were included, as well as 40 092 age-matched patients with essential hypertension. Despite similar blood pressure at study entry and throughout follow-up, patients with PA who were treated with MR antagonists whose renin remained suppressed had a higher risk for incident AF than patients with essential hypertension (adjusted HR, 2.55 [95% CI, 1.75-3.71]). They also had an adjusted 10-year cumulative AF incidence difference of 14.1 (95% CI, 6.7-21.5) excess cases per 100 persons compared with patients with essential hypertension. In contrast, patients with PA who were treated with MR antagonists and whose renin increased and patients with PA who were treated with surgical adrenalectomy had no statistically significant difference in risk for incident AF compared with patients with essential hypertension. Conclusions and Relevance: When compared with patients with essential hypertension, patients with PA treated with MR antagonists such that renin remained suppressed (as a proxy for insufficient MR blockade) had a significantly higher risk for incident AF; however, treatment of PA with MR antagonists to substantially increase renin (suggesting sufficient MR blockade), or with surgical adrenalectomy (to remove the source of aldosteronism), was associated with no significant difference in risk for developing AF. These findings add to the growing body of evidence suggesting that MR blockade may be a potential therapy to decrease the incidence of AF.

Renal Outcomes in Medically and Surgically Treated Primary Aldosteronism.

Lifelong therapy with mineralocorticoid receptor antagonists (MRAs) or surgical adrenalectomy are the recommended treatments for primary aldosteronism (PA). Whether these treatments mitigate the risk for kidney disease remains unknown. We performed a retrospective cohort study of patients with PA treated with MRAs (N=400) or surgical adrenalectomy (N=120) and age- and estimated glomerular filtration rate-matched patients with essential hypertension (N=15 474) to determine risk for chronic kidney disease and longitudinal estimated glomerular filtration rate decline. Despite similar blood pressures, patients with PA treated with MRAs had a higher risk for incident chronic kidney disease compared with essential hypertension patients (adjusted hazard ratio, 1.63; 95% confidence interval, 1.33-1.99). Correspondingly, the adjusted annual decline in estimated glomerular filtration rate was greater in PA patients treated with MRAs compared with essential hypertension patients (-1.6; 95% confidence interval, -1.4 to -1.8 versus -0.9; 95% confidence interval, -0.9 to -1.0 mL/min per 1.73 m2/y; P<0.001). In contrast, patients with unilateral PA treated with surgical adrenalectomy had no significant difference in risk for incident chronic kidney disease or in an annual decline in estimated glomerular filtration rate compared with essential hypertension patients. Among PA patients with diabetes mellitus treated with MRAs, there was a higher risk for incident albuminuria compared with essential hypertension (adjusted hazard ratio, 2.52; 95% confidence interval, 1.28-4.96). MRA therapy in PA is associated with higher risk for developing chronic kidney disease when compared with essential hypertension, and surgical adrenalectomy may mitigate this risk. When possible, curative surgical adrenalectomy may be superior to lifelong MRA therapy in preventing kidney disease in PA.

Cardiometabolic outcomes and mortality in medically treated primary aldosteronism: a retrospective cohort study.

BACKGROUND: Mineralocorticoid receptor (MR) antagonists are the recommended medical therapy for primary aldosteronism. Whether this recommendation effectively reduces cardiometabolic risk is not well understood. We aimed to investigate the risk of incident cardiovascular events in patients with primary aldosteronism treated with MR antagonists compared with patients with essential hypertension. METHODS: We did a cohort study using patients from a research registry from Brigham and Women's Hospital, Massachusetts General Hospital, and their affiliated partner hospitals. We identified patients with primary aldosteronism using International Classification of Disease, 9th and 10th Revision codes, who were assessed between the years 1991-2016 and were at least 18 years of age. We excluded patients who underwent surgical adrenalectomy, had a previous cardiovascular event, were not treated with MR antagonists, or had no follow-up visits after study entry. From the same registry, we identified a population with essential hypertension that was frequency matched by decade of age at study entry. We extracted patient cohort data and collated it into a de-identified database. The primary outcome was an incident cardiovascular event, defined as a composite of incident myocardial infarction or coronary revascularisation, hospital admission with congestive heart failure, or stroke, which was assessed using adjusted Cox regression models. Secondary outcomes were the individual components of the composite cardiovascular outcome, as well as incident atrial fibrillation, incident diabetes, and death. FINDINGS: We identified 602 eligible patients with primary aldosteronism treated with MR antagonists and 41 853 age-matched patients with essential hypertension from the registry. The two groups of patients had comparable cardiovascular risk profiles and blood pressure throughout the study. The incidence of cardiovascular events was higher in patients with primary aldosteronism on MR antagonists than in patients with essential hypertension (56·3 [95% CI 48·8-64·7] vs 26·6 [26·1-27·2] events per 1000 person-years, adjusted hazard ratio 1·91 [95% CI 1·63-2·25]; adjusted 10-year cumulative incidence difference 14·1 [95% CI 10·1-18·0] excess events per 100 people). Patients with primary aldosteronism also had higher adjusted risks for incident mortality (hazard ratio [HR] 1·34 [95% CI 1·06-1·71]), diabetes (1·26 [1·01-1·57]), and atrial fibrillation (1·93 [1·54-2·42]). Compared with essential hypertension, the excess risk for cardiovascular events and mortality was limited to patients with primary aldosteronism whose renin activity remained suppressed (<1 µg/L per h) on MR antagonists (adjusted HR [2·83 [95% CI 2·11-3·80], and 1·79 [1·14-2·80], respectively) whereas patients who were treated with higher MR antagonist doses and had unsuppressed renin (≥1 µg/L per h) had no significant excess risk. INTERPRETATION: The current practice of MR antagonist therapy in primary aldosteronism is associated with significantly higher risk for incident cardiometabolic events and death, independent of blood pressure control, than for patients with essential hypertension. Titration of MR antagonist therapy to raise renin might mitigate this excess risk. FUNDING: US National Institutes of Health.

Myb permits multilineage airway epithelial cell differentiation.

The epithelium of the pulmonary airway is specially differentiated to provide defense against environmental insults, but also subject to dysregulated differentiation that results in lung disease. The current paradigm for airway epithelial differentiation is a one-step program whereby a p63(+) basal epithelial progenitor cell generates a ciliated or secretory cell lineage, but the cue for this transition and whether there are intermediate steps are poorly defined. Here, we identify transcription factor Myb as a key regulator that permits early multilineage differentiation of airway epithelial cells. Myb(+) cells were identified as p63(-) and therefore distinct from basal progenitor cells, but were still negative for markers of differentiation. Myb RNAi treatment of primary-culture airway epithelial cells and Myb gene deletion in mice resulted in a p63(-) population with failed maturation of Foxj1(+) ciliated cells as well as Scbg1a1(+) and Muc5ac(+) secretory cells. Consistent with these findings, analysis of whole genome expression of Myb-deficient cells identified Myb-dependent programs for ciliated and secretory cell differentiation. Myb(+) cells were rare in human airways but were increased in regions of ciliated cells and mucous cell hyperplasia in samples from subjects with chronic obstructive pulmonary disease. Together, the results show that a p63(-) Myb(+) population of airway epithelial cells represents a distinct intermediate stage of differentiation that is required under normal conditions and may be heightened in airway disease.