Race, obesity, and the renin-angiotensin-aldosterone system: treatment response in children with primary hypertension

The Study of the Epidemiology of Pediatric Hypertension Registry (SUPERHERO): rationale and methods

Despite increasing prevalence of hypertension in youth and high adult cardiovascular mortality rates, the long-term consequences of youth-onset hypertension remain unknown. This is due to limitations of prior research, such as small sample sizes, reliance on manual record review, and limited analytic methods, that did not address major biases. The Study of the Epidemiology of Pediatric Hypertension (SUPERHERO) is a multisite, retrospective registry of youth evaluated by subspecialists for hypertension disorders. Sites obtain harmonized electronic health record data using standardized biomedical informatics scripts validated with randomized manual record review. Inclusion criteria are index visit for International Classification of Diseases, 10th Revision (ICD-10) code-defined hypertension disorder on or after January 1, 2015, and age < 19 years. We exclude patients with ICD-10 code-defined pregnancy, kidney failure on dialysis, or kidney transplantation. Data include demographics, anthropomorphics, US Census Bureau tract, histories, blood pressure, ICD-10 codes, medications, laboratory and imaging results, and ambulatory blood pressure. SUPERHERO leverages expertise in epidemiology, statistics, clinical care, and biomedical informatics to create the largest and most diverse registry of youth with newly diagnosed hypertension disorders. SUPERHERO's goals are to reduce CVD burden across the life course and establish gold-standard biomedical informatics methods for youth with hypertension disorders.

Prevalence of left ventricular hypertrophy in children and young people with primary hypertension: Meta-analysis and meta-regression

BACKGROUND

Left ventricular hypertrophy (LVH) is the main marker of HMOD in children and young people (CYP). We aimed to assess the prevalence of LVH and its determinants in CYP with primary hypertension (PH).

METHODS

A meta-analysis of prevalence was performed. A literature search of articles reporting LVH in CYP with PH was conducted in Medline, Embase, and Cochrane databases. Studies with a primary focus on CYP (up to 21 years) with PH were included. Meta-regression was used to analyze factors explaining observed heterogeneity.

RESULTS

The search yielded a total of 2,200 articles, 153 of those underwent full-text review, and 47 reports were included. The reports evaluated 51 study cohorts including 5,622 individuals, 73% male subjects, and a mean age of 13.6 years. LVH was defined as left ventricle mass index (LVMI) ≥ 95th percentile in 22 (47%), fixed cut-off ≥38.6 g/m2.7 in eight (17%), sex-specific fixed cut-off values in six (13%), and miscellaneously in others. The overall prevalence of LVH was 30.5% (95% CI 27.2-33.9), while heterogeneity was high (I 2 = 84%). Subgroup analysis including 1,393 individuals (76% male subjects, mean age 14.7 years) from pediatric hypertension specialty clinics and LVH defined as LVMI ≥95th percentile only (19 study cohorts from 18 studies), reported prevalence of LVH at 29.9% (95% CI 23.9 to 36.3), and high heterogeneity (I 2 = 84%). Two studies involving patients identified through community screening (n = 1,234) reported lower LVH prevalence (21.5%). In the meta-regression, only body mass index (BMI) z-score was significantly associated with LVH prevalence (estimate 0.23, 95% CI 0.08-0.39, p = 0.004) and accounted for 41% of observed heterogeneity, but not age, male percentage, BMI, or waist circumference z-score. The predominant LVH phenotype was eccentric LVH in patients from specialty clinics (prevalence of 22% in seven studies with 779 participants) and one community screening study reported the predominance of concentric LVH (12%).

CONCLUSION

Left ventricular hypertrophy is evident in at least one-fifth of children and young adults with PH and in nearly a third of those referred to specialty clinics with a predominant eccentric LVH pattern in the latter. Increased BMI is the most significant risk association for LVH in hypertensive youth.

When Hypertension Grows Up: Implications for Transitioning Care of Adolescents and Young Adults With Hypertension From Pediatric to Adult Health Care Providers

Hypertension (HTN) is an important cause of morbidity and mortality in children as well as adults. HTN and related adverse cardiovascular health develop and progress on a continuum across an individual's life course. Pediatric HTN, or even isolated elevated blood pressure as a child, increases the risk of sustained HTN and cardiovascular disease in later adulthood. Transitioning the care of adolescents and young adults who have HTN is an important but unmet health care need that could potentially have a dramatic effect on mitigating the risk of cardiovascular disease in adulthood. However, very little has been published about the transition process in this population, and considerable gaps in the field remain. We discuss the epidemiology, etiology, and management approach in youth with HTN and how they differ from adults. We contextualize HTN and cardiovascular health on a continuum across the life course. We discuss key considerations for the transition process for adolescents and young adults with HTN including the major barriers that exist. Finally, we review key immediate health care needs that are particularly important around the time of the transfer of care.

Correlation between kidney sodium and potassium handling and the renin-angiotensin-aldosterone system in children with hypertensive disorders

BACKGROUND

Urine sodium and potassium are used as surrogate markers for dietary consumption in adults with hypertension, but their role in youth with hypertension and their association with components of the renin-angiotensin-aldosterone system (RAAS) are incompletely characterized. Some individuals with hypertension may have an abnormal RAAS response to dietary sodium and potassium intake, though this is incompletely described. Our objective was to investigate if plasma renin activity and serum aldosterone are associated with urine sodium and potassium in youth referred for hypertensive disorders.

METHODS

This pilot study was a cross-sectional analysis of baseline data from 44 youth evaluated for hypertensive disorders in a Hypertension Clinic. We recorded urine sodium and potassium concentrations normalized to urine creatinine, plasma renin activity, and serum aldosterone and calculated the sodium/potassium (UNaK) and aldosterone/renin ratios. We used multivariable generalized linear models to estimate the associations of renin and aldosterone with urine sodium and potassium.

RESULTS

Our cohort was diverse (37% non-Hispanic Black, 14% Hispanic), 66% were male, and median age was 15.3 years; 77% had obesity and 9% had a secondary etiology. Aldosterone was associated inversely with urine sodium/creatinine (β: -0.34, 95% CI -0.62 to -0.06) and UNaK (β: -0.09, 95% CI -0.16 to -0.03), and adjusted for estimated glomerular filtration rate and serum potassium.

CONCLUSIONS

Higher serum aldosterone levels, but not plasma renin activity, were associated with lower urine sodium/creatinine and UNaK at baseline in youth referred for hypertensive disorders. Further characterization of the RAAS could help define hypertension phenotypes and guide management. A higher resolution version of the Graphical abstract is available as supplementary information.

Fibroblast growth factor 23-Klotho and hypertension: experimental and clinical mechanisms

Hypertension (HTN) and chronic kidney disease (CKD) are increasingly recognized in pediatric patients and represent risk factors for cardiovascular morbidity and mortality later in life. In CKD, enhanced tubular sodium reabsorption is a leading cause of HTN due to augmented extracellular fluid volume expansion. The renin-angiotensin-aldosterone system (RAAS) upregulates various tubular sodium cotransporters that are also targets of the hormone fibroblast growth factor 23 (FGF23) and its co-receptor Klotho. FGF23 inhibits the activation of 1,25-dihydroxyvitamin D that is a potent suppressor of renin biosynthesis. Here we review the complex interactions and disturbances of the FGF23-Klotho axis, vitamin D, and the RAAS relevant to blood pressure regulation and discuss the therapeutic strategies aimed at mitigating their pathophysiologic contributions to HTN.

Evaluating sources of bias in observational studies of angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker use during COVID-19: beyond confounding

Concerns over ACE inhibitor or ARB use to treat hypertension during COVID-19 remain unresolved. Although studies using more robust methodologies provided some clarity, sources of bias persist and it remains critical to quickly address this question. In this review, we discuss pernicious sources of bias using a causal model framework, including time-varying confounder, collider, information, and time-dependent bias, in the context of recently published studies. We discuss causal inference methodologies that can address these issues, including causal diagrams, time-to-event analyses, sensitivity analyses, and marginal structural modeling. We discuss effect modification and we propose a role for causal mediation analysis to estimate indirect effects via mediating factors, especially components of the renin--angiotensin system. Thorough knowledge of these sources of bias and the appropriate methodologies to address them is crucial when evaluating observational studies to inform patient management decisions regarding whether ACE inhibitors or ARBs are associated with greater risk from COVID-19.

ACE2 (Angiotensin-Converting Enzyme 2), COVID-19, and ACE Inhibitor and Ang II (Angiotensin II) Receptor Blocker Use During the Pandemic: The Pediatric Perspective

Potential but unconfirmed risk factors for coronavirus disease 2019 (COVID-19) in adults and children may include hypertension, cardiovascular disease, and chronic kidney disease, as well as the medications commonly prescribed for these conditions, ACE (angiotensin-converting enzyme) inhibitors, and Ang II (angiotensin II) receptor blockers. Coronavirus binding to ACE2 (angiotensin-converting enzyme 2), a crucial component of the renin-angiotensin-aldosterone system, underlies much of this concern. Children are uniquely impacted by the coronavirus, but the reasons are unclear. This review will highlight the relationship of COVID-19 with hypertension, use of ACE inhibitors and Ang II receptor blockers, and lifetime risk of cardiovascular disease from the pediatric perspective. We briefly summarize the renin-angiotensin-aldosterone system and comprehensively review the literature pertaining to the ACE 2/Ang-(1-7) pathway in children and the clinical evidence for how ACE inhibitors and Ang II receptor blockers affect this important pathway. Given the importance of the ACE 2/Ang-(1-7) pathway and the potential differences between adults and children, it is crucial that children are included in coronavirus-related research, as this may shed light on potential mechanisms for why children are at decreased risk of severe COVID-19.

Relationship between food insecurity and high blood pressure in a national sample of children and adolescents

OBJECTIVES

To determine the relationship between food insecurity (FI) and high blood pressure (BP) in a national cohort of children and adolescents.

METHODS

A cross-sectional analysis of children aged 8-17 years in the 2007-2014 National Health and Nutrition Examination Survey (NHANES; unweighted N = 7125). FI over the preceding 12 months was assessed using the USDA Household Food Security Scale in NHANES. We defined high BP as (i) systolic or diastolic BP ≥ 90% for age < 13 years or ≥ 120/80 mmHg for age ≥ 13 years measured at one visit or (ii) reported hypertension diagnosis or current antihypertensive medication use. We used multivariable logistic regression to determine the association between household and child-specific FI and high BP, controlling for age, sex, race, and household income, accounting for the complex NHANES survey design.

RESULTS

The study population was 14.4% black, 21.3% Hispanic, and 49.4% female with a mean age of 12.6 years (SD 2.9). 20.3% had FI and 12.8% had high BP. High BP was more common in household FI vs. food-secure subjects (15.3% vs. 12.1%, p = 0.003). Adjusted analysis confirmed that household FI and child FI were associated with high BP (OR 1.26, 95% CI 1.04-1.54; OR 1.42, 95% CI 1.03-1.96, respectively).

CONCLUSIONS

Household and child FI were associated with an increased likelihood of high BP in a large nationally representative cohort of children and adolescents. FI may have a significant impact on cardiovascular health during childhood. Further research is warranted to better define how FI contributes to health disparities.