Primary aldosteronism in the primary care setting

Treating Primary Aldosteronism-Induced Hypertension: Novel Approaches and Future Outlooks

Primary aldosteronism (PA) is the most common cause of secondary hypertension and is associated with increased morbidity and mortality when compared with blood pressure-matched cases of primary hypertension. Current limitations in patient care stem from delayed recognition of the condition, limited access to key diagnostic procedures, and lack of a definitive therapy option for nonsurgical candidates. However, several recent advances have the potential to address these barriers to optimal care. From a diagnostic perspective, machine-learning algorithms have shown promise in the prediction of PA subtypes, while the development of noninvasive alternatives to adrenal vein sampling (including molecular positron emission tomography imaging) has made accurate localization of functioning adrenal nodules possible. In parallel, more selective approaches to targeting the causative aldosterone-producing adrenal adenoma/nodule (APA/APN) have emerged with the advent of partial adrenalectomy or precision ablation. Additionally, the development of novel pharmacological agents may help to mitigate off-target effects of aldosterone and improve clinical efficacy and outcomes. Here, we consider how each of these innovations might change our approach to the patient with PA, to allow more tailored investigation and treatment plans, with corresponding improvement in clinical outcomes and resource utilization, for this highly prevalent disorder.

Insights into diagnostic errors in endocrinology: a prospective, case-based, international study

BACKGROUND

Diagnostic errors in internal medicine are common. While cognitive errors have previously been identified to be the most common contributor to errors, very little is known about errors in specific fields of internal medicine such as endocrinology. This prospective, multicenter study focused on better understanding the causes of diagnostic errors made by general practitioners and internal specialists in the area of endocrinology.

METHODS

From August 2019 until January 2020, 24 physicians completed five endocrine cases on an online platform that simulated the diagnostic process. After each case, the participants had to state and explain why they chose their assumed diagnosis. The data gathering process as well as the participants' explanations were quantitatively and qualitatively analyzed to determine the causes of the errors. The diagnostic processes in correctly and incorrectly solved cases were compared.

RESULTS

Seven different causes of diagnostic error were identified, the most frequent being misidentification (mistaking one diagnosis with a related one or with more frequent and similar diseases) in 23% of the cases. Other causes were faulty context generation (21%) and premature closure (17%). The diagnostic confidence did not differ between correctly and incorrectly solved cases (median 8 out of 10, p = 0.24). However, in incorrectly solved cases, physicians spent less time on the technical findings (such as lab results, imaging) (median 250 s versus 199 s, p < 0.049).

CONCLUSIONS

The causes for errors in endocrine case scenarios are similar to the causes in other fields of internal medicine. Spending more time on technical findings might prevent misdiagnoses in everyday clinical practice.

Prevalence of Cortisol Cosecretion in Patients With Primary Aldosteronism: Role of Metanephrine in Adrenal Vein Sampling

CONTEXT

Adrenal venous sampling (AVS) is the gold standard procedure for subtype diagnosis in patients with primary aldosteronism (PA). Cortisol is usually adopted for the normalization of aldosterone levels in peripheral and adrenal samples. However, asymmetrical cortisol secretion can potentially affect the lateralization index, leading to subtype misdiagnosis.

OBJECTIVE

We aimed to assess the prevalence of asymmetrical cortisol secretion in patients undergoing AVS and whether variations in adrenal vein cortisol might influence AVS interpretations. We then evaluated the use of metanephrines for the normalization of aldosterone levels for lateralization index.

METHODS

We retrospectively included 101 patients with PA who underwent AVS: 49 patients underwent unstimulated AVS, while 52 patients underwent both unstimulated and cosyntropin-stimulated AVS. Eighty-eight patients had bilateral successful AVS according to metanephrine ratio. We assessed the prevalence of asymmetrical cortisol secretion through the cortisol to metanephrine (C/M) lateralization index (LI). We then evaluated whether the use of aldosterone to metanephrine (A/M) LI can improve the diagnostic accuracy of AVS compared with aldosterone to cortisol (A/C) LI.

RESULTS

Asymmetrical cortisol secretion is present in 18% of patients with PA. Diagnosis with A/M LI and A/C LI is discordant in 14% of patients: 9% had a diagnosis of unilateral PA with A/M LI instead of bilateral PA with A/C LI and 5% had a diagnosis of bilateral PA with A/M LI instead of unilateral PA.

CONCLUSION

The assessment of metanephrine levels in AVS is useful for the determination of selectivity and lateralization, allowing an accurate diagnosis, especially in patients with asymmetrical cortisol secretion.

Assessment of biochemical outcomes in patients with primary aldosteronism after adrenalectomy based on CT scan diagnosis of unilateral adenoma without adrenal vein sampling

PURPOSE

The purpose of this study was to assess the surgical outcomes of patients with primary aldosteronism when surgery was based only on CT finding of unilateral adenoma without adrenal vein sampling (AVS).

METHODS

This is a retrospective review of the records of patients who had undergone retroperitoneal laparoscopic adrenalectomy for primary aldosteronism based on CT scan finding of unilateral adenoma and had a follow-up of at least 6-12 months from January 2012 to December 2020 in a single center; decision for adrenalectomy was based on CT scan, and AVS was not used. The clinical and biochemical outcomes were accessed using the standardized primary aldosteronism surgical outcome (PASO) criteria. Patient's demographics and preoperative factors were analyzed to assess for independent predictor of surgical success.

RESULTS

According to the PASO criteria, 172 patients finally enrolled in the training dataset, and 20 patients enrolled in the validation dataset. In the training dataset, complete clinical success was achieved in 71 patients (41.3%), partial success in 87 (50.6%), and absent success in 14 (8.1%). Biochemical outcomes showed that 151 patients (87.8%) were completely cured, 14 patients (8.1%) got a partial biochemical success, and an absent biochemical success was found in seven patients (4.1%). Multivariate logistic regression analysis showed that age, body mass index (BMI), tumor size, mean arterial pressure (MAP), and serum potassium were the most independent factors for incomplete biochemical success. Based on the results of statistical analysis, our study constructed a nomogram prognostic evaluation model for patients after unilateral primary aldosterone surgery.

CONCLUSIONS

Laparoscopic adrenalectomy for patients with primary aldosteronism base on CT scan finding of a unilateral adenoma without AVS had a high rate of complete biochemical cure at 12 months. Risk factors for incomplete biochemical success include age, BMI, tumor size, MAP, and serum potassium. Our study constructed a nomogram prognostic evaluation model for patients after unilateral primary aldosterone surgery. The nomogram accurately and reliably predicted the incomplete biochemical success.

Screening for primary aldosteronism in the hypertensive obstructive sleep apnea population is cost-saving

BACKGROUND

Guidelines recommend screening for primary aldosteronism in patients diagnosed with hypertension and obstructive sleep apnea. Recent studies have shown that adherence to these recommendations is extremely low. It has been suggested that cost is a barrier to implementation. No analysis has been done to rigorously evaluate the cost-effectiveness of widespread implementation of these guidelines.

METHODS

We constructed a decision-analytic model to evaluate screening of the hypertensive obstructive sleep apnea population for primary aldosteronism as per guideline recommendations in comparison with current rates of screening. Probabilities, utility values, and costs were identified in the literature. Threshold and sensitivity analyses assessed robustness of the model. Costs were represented in 2020 US dollars and health outcomes in quality-adjusted life-years. The model assumed a societal perspective with a lifetime time horizon.

RESULTS

Screening per guideline recommendations had an expected cost of $47,016 and 35.27 quality-adjusted life-years. Continuing at current rates of screening had an expected cost of $48,350 and 34.86 quality-adjusted life-years. Screening was dominant, as it was both less costly and more effective. These results were robust to sensitivity analysis of disease prevalence, test sensitivity, patient age, and expected outcome of medical or surgical treatment of primary aldosteronism. The screening strategy remained cost-effective even if screening were conservatively presumed to identify only 3% of new primary aldosteronism cases.

CONCLUSIONS

For patients with hypertension and obstructive sleep apnea, rigorous screening for primary aldosteronism is cost-saving due to cardiovascular risk averted. Cost should not be a barrier to improving primary aldosteronism screening adherence.

The spectrum of low-renin hypertension

Low-renin hypertension (LRH) is a frequent condition in patients with arterial hypertension, accounting for 30% of patients. Monogenic forms can cause LRH in a minority of cases. However, in the large majority of patients, LRH is caused by the combined effects of congenital and acquired factors, comprising dietary habits. Several genetic variants have been proposed as co-factors in the pathogenesis of LRH with normal-low serum aldosterone. Emerging evidences support the hypothesis that a large proportion of LRH with normal-high serum aldosterone is associated with subclinical primary aldosteronism (PA). The recent identification of aldosterone-producing cell clusters (APCCs) as the possible cause of subclinical PA, further supported the concept of a continuous spectrum of autonomous aldosterone secretion, from subclinical forms towards overt PA. In this review we describe the main aspects of LRH, focusing on molecular basis, clinical risk profile and patients' management.

Primary aldosteronism in a general population sample. The Czech post-MONICA study

Purpose: Primary aldosteronism (PA) is considered the most common form of secondary hypertension, however, its prevalence, particularly in a general population, is still a matter of debate. The aim of our study was to evaluate the prevalence of PA in a randomly selected general population sample.Materials and methods: A total of 1940 individuals (1% population random sample) aged 25-64 years were screened for major cardiovascular risk factors in six districts of the Czech Republic. Hypertension was defined as a mean of two blood pressure readings ≥140/90 mmHg at one visit or taking antihypertensive medication. Within this population, 740 individuals were labelled as hypertensives and 650 of them sampled for the analysis of direct plasma renin and serum aldosterone. The diagnosis of PA was based on elevated serum aldosterone, low plasma renin and high aldosterone/renin (ARR) ratio and was also verified by a confirmatory test with saline infusion.Results: Positive ARR was found in 52 (8%) individuals (64% women, 36% men, however, due to substatntial proportion of reluctatnt participants to undergo a further work-up (27%), we could confirm the diagnosis of PA only in 13 of them (2%). Aldosterone-producing adenoma was found in one case only, seven patients had idiopathic type and five individuals refused potential surgical treatment therefore, adrenal venous sampling was not performed.Conclusion: Elevated serum aldosterone together with low renin and high ARR were found in 52 (8%) of hypertensives selected from a general population sample, however, the diagnosis of PA was confirmed only in 13 of them (2%). This study based on a general population survey highlighted the difficulty of conducting epidemiological studies on primary aldosteronism in a relatively healthy cohort part of whom did not provide the level of collaboration that is necessary to assess the true prevalence of this condition.

Proteomic Landscape of Aldosterone-Producing Adenoma

Primary aldosteronism is a disease of excessive production of adrenal steroid hormones and the most common cause of endocrine hypertension. Primary aldosteronism results mainly from bilateral adrenal hyperplasia or unilateral aldosterone-producing adenoma (APA). Primary aldosteronism cause at the molecular level is incompletely understood and a targeted treatment preventing excessive adrenal steroid production is not available. Here, we perform deep quantitative proteomic and phosphoproteomic profiling of 6 pairs of APA and adjacent nontumoral adrenal cortex. We show that increased steroidogenesis in APA is accompanied by upregulation of steroidogenic enzymes (HSD3B2, CYP21A2, CYP11B2) and of proteins involved in cholesterol uptake (LSR). We demonstrate that HSD3B2 is phosphorylated at Ser95 or 96 and identify a novel phosphorylation site, Ser489, in CYP21A2, suggesting that steroidogenic enzymes are regulated by phosphorylation. Our analysis also reveals altered ECM (extracellular matrix) composition in APA that affects ECM-cell surface interactions and actin cytoskeleton rearrangements. We show that RHOC, a GTPase controlling actin organization in response to extracellular stimuli, is upregulated in APA and promotes expression of the aldosterone synthase gene CYP11B2. Our data also indicate deregulation of protein N-glycosylation and GABAergic signaling in APAs. Finally, we find that mTORC1 (mammalian target of rapamycin complex 1) signaling is the major pathway deregulated in APA. Our study provides a rich resource for future research on the molecular mechanisms of primary aldosteronism.

Primary Aldosteronism and Obstructive Sleep Apnea: A Cross-Sectional Multi-Ethnic Study

The association between primary aldosteronism (PA) and obstructive sleep apnea (OSA) has been a matter of debate. 2016 Endocrine Society guideline recommends screening for PA all hypertensive patients with OSA. We designed a multicenter, multiethnic, cross-sectional study to evaluate the prevalence of PA in patients with OSA and the prevalence of OSA in unselected patients with PA. Two hundred and three patients with OSA (102 whites and 101 Chinese) were screened for PA, and 207 patients with PA (104 whites, 100 Chinese, and 3 of African descent) were screened for OSA by cardiorespiratory polygraphy. Eighteen patients with OSA (8.9%) had PA (11.8% of white and 5.9% of Chinese ethnicity). In patients without other indications for PA screening, the prevalence of PA dropped to 1.5%. The prevalence of OSA in patients with PA was 67.6%, consistent in both white and Chinese patients. A correlation between aldosterone levels and apnea/hypopnea index was observed in white patients with PA (R²=0.225, P=0.016) but not in Chinese patients. Multinomial logistic regression confirmed a significant and independent association between plasma aldosterone levels and moderate to severe OSA diagnosis in white patients (odds ratio, 1.002; P=0.002). In conclusion, aldosterone levels may contribute to the severity of OSA in white patients with hyperaldosteronism, but patients with OSA are not at high risk of PA. Results of the present study challenge the current recommendation of the Endocrine Society guideline that all patients with OSA should be screened for PA, irrespective of the grade of hypertension.

A prediction model for primary aldosteronism when the salt loading test is inconclusive

OBJECTIVE

To develop a prediction model to confirm or exclude primary aldosteronism (PA) in patients with an inconclusive salt loading test (SLT).

CONTEXT

Diagnosis in patients with a suspicion of PA can be confirmed using an SLT. In case of inconclusive test results the decision about how to manage the patient is usually based on contextual clinical data.

DESIGN

We included a retrospective cohort of 276 patients in the final analysis.

METHODS

All patients underwent an SLT between 2005 and 2016 in our university medical center. The SLT was inconclusive (post-infusion aldosterone levels 140-280 pmol/L) in 115 patients. An expert panel then used contextual clinical data to diagnose PA in 45 of them. Together with 101 patients with a positive SLT this resulted in a total of 146 patients with PA. A total of 11 variables were used in a multivariable logistic regression analysis. We assessed internal validity by bootstrapping techniques.

RESULTS

The following variables were independently associated with PA: more intense potassium supplementation, lower plasma potassium concentration, lower plasma renin concentration before SLT and higher plasma aldosterone concentration after SLT. The resulting prediction model had a sensitivity of 84.4% and a specificity of 94.3% in patients with an inconclusive SLT. The positive and negative predictive values were 90.5 and 90.4%, respectively.

CONCLUSIONS

We developed a prediction model for the diagnosis of PA in patients with an inconclusive SLT that results in a diagnosis that was in high agreement with that of an expert panel.