A multicenter study of neurocognition in children with hypertension: methods, challenges, and solutions

Neurocognition in Pediatric Chronic Kidney Disease: A Review of Data From the Chronic Kidney Disease in Children (CKiD) Study

Pediatric chronic kidney disease (CKD) is associated with deficits in neurocognitive functioning, ranging from mild to severe, and correlated with the severity of kidney disease. Clinical variables that are associated with neurocognitive deficits include lower kidney function, hypertension, proteinuria, and metabolic acidosis. Commonly reported neurocognitive difficulties include academic underachievement and deficits in attention regulation and executive function as well as somewhat lower intellectual abilities compared with peer and normative data. Although often mild, these neurocognitive deficits may have broad implications for quality of life and likely contribute to both poorer high school graduation rates and long-term underemployment in the adult CKD population. The presence of neurocognitive deficits in predialytic CKD has been well characterized, but further longitudinal research is warranted to describe cognitive changes as children progress from early stage CKD to kidney replacement therapy. Such studies should include both cognitive and neuroimaging evaluations to better inform the impact of CKD progression on neurocognitive outcomes.

Childhood Hypertension and Effects on Cognitive Functions: Mechanisms and Future Perspectives

Pediatric hypertension is currently one of the most common health concerns in children, given its effects not only on cardiovascular but also cognitive functions. There is accumulating evidence suggesting neurocognitive dysfunction in hypertensive children that could persist even into adulthood. Identifying the precise mechanism(s) underlying the association between childhood hypertension and cognitive dysfunction is crucial as it could potentially lead to the discovery of "druggable" biological targets facilitating the development of treatments. Here, we discuss some of the proposed pathophysiological mechanisms underlying childhood hypertension and cognitive deficits and suggest strategies to address some of the current challenges in the field. The various research studies involving hypertensive adults indicate that long-term hypertension may produce abnormal cerebrovascular reactivity, chronic inflammation, autonomic dysfunction, or hyperinsulinemia and hypercholesterolemia, which could lead to alterations in the brain's structure and functions, resulting in cognitive dysfunction. In light of the current literature, we propose that dysregulation of the hypothalamus-pituitaryadrenal axis, modifications in endothelial brain-derived neurotrophic factor and the gut microbiome may also modulate cognitive functions in hypertensive individuals. Moreover, the above-mentioned pathological states may further intensify the detrimental effects of hypertension on cognitive functions. Thus, treatments that target not only hypertension but also its downstream effects may prove useful in ameliorating hypertension-induced cognitive deficits. Much remains to be clarified about the mechanisms and treatments of hypertension-induced cognitive outcomes in pediatric populations. Addressing the knowledge gaps in this field entails conducting not only clinical research but also rigorous basic and translational studies.

Ambulatory blood pressure monitoring and neurocognitive function in children with primary hypertension

BACKGROUND

Children with primary hypertension have been reported to have diminished scores in measures of cognition. However, little is known about the relative correlation between office and ambulatory blood pressure (BP) and neurocognitive test performance, and whether short-term BP variability is associated with decreased neurocognitive function. We sought to determine whether ambulatory BP monitoring (ABPM) was more strongly associated with neurocognitive test performance compared with office BP, and whether increased short-term BP variability was associated with lower neurocognitive scores.

METHODS

Seventy-five subjects ages 10-18 years, with untreated primary hypertension, and 75 matched normotensive controls completed neurocognitive testing. All subjects had office BP and ABPM prior to neurocognitive testing.

RESULTS

On multivariate analyses, there was no significant association between office BP and neurocognitive tests. However, several ABPM parameters were significantly associated with neurocognitive test scores in the lower quartile, in particular 24 h SBP load and wake systolic blood pressure (SBP) index [Rey Auditory Verbal learning Test (RAVLT) List A Trial 1, 24 h SBP load, odds ratio (OR) = 1.02, wake SBP index, OR = 1.06; List A Total, 24 h SBP load, OR = 1.02, wake SBP index, OR = 1.06; Short Delay Recall, wake SBP index, OR = 1.06; CogState Maze delayed recall, 24 h SBP load, OR = 1.03, wake SBP index, OR = 1.08; Grooved Pegboard, 24 h SBP load, OR = 1.02; all p < 0.05]. In contrast, short-term BP variability measures were not associated with neurocognitive test performance.

CONCLUSIONS

ABPM is superior to office BP in distinguishing hypertensive youth with lower neurocognitive test performance.

Neurocognitive Function in Children with Primary Hypertension after Initiation of Antihypertensive Therapy

OBJECTIVE

To determine the change in neurocognitive test performance in children with primary hypertension after initiation of antihypertensive therapy.

STUDY DESIGN

Subjects with hypertension and normotensive control subjects had neurocognitive testing at baseline and again after 1 year, during which time the subjects with hypertension received antihypertensive therapy. Subjects completed tests of general intelligence, attention, memory, executive function, and processing speed, and parents completed rating scales of executive function.

RESULTS

Fifty-five subjects with hypertension and 66 normotensive control subjects underwent both baseline and 1-year assessments. Overall, the blood pressure (BP) of subjects with hypertension improved (24-hour systolic BP load: mean baseline vs 1 year, 58% vs 38%, P < .001). Primary multivariable analyses showed that the hypertension group improved in scores of subtests of the Rey Auditory Verbal Learning Test, Grooved Pegboard, and Delis-Kaplan Executive Function System Tower Test (P < .05). However, the control group also improved in the same measures with similar effects sizes. Secondary analyses by effectiveness of antihypertensive therapy showed that subjects with persistent ambulatory hypertension at 1 year (n = 17) did not improve in subtests of Rey Auditory Verbal Learning Test and had limited improvement in Grooved Pegboard.

CONCLUSIONS

Overall, children with hypertension did not improve in neurocognitive test performance after 1 year of antihypertensive therapy, beyond that also seen in normotensive controls, suggesting improvements with age or practice effects because of repeated neurocognitive testing. However, the degree to which antihypertensive therapy improves BP may affect its impact upon neurocognitive function.

Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents

These pediatric hypertension guidelines are an update to the 2004 "Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents." Significant changes in these guidelines include (1) the replacement of the term "prehypertension" with the term "elevated blood pressure," (2) new normative pediatric blood pressure (BP) tables based on normal-weight children, (3) a simplified screening table for identifying BPs needing further evaluation, (4) a simplified BP classification in adolescents ≥13 years of age that aligns with the forthcoming American Heart Association and American College of Cardiology adult BP guidelines, (5) a more limited recommendation to perform screening BP measurements only at preventive care visits, (6) streamlined recommendations on the initial evaluation and management of abnormal BPs, (7) an expanded role for ambulatory BP monitoring in the diagnosis and management of pediatric hypertension, and (8) revised recommendations on when to perform echocardiography in the evaluation of newly diagnosed hypertensive pediatric patients (generally only before medication initiation), along with a revised definition of left ventricular hypertrophy. These guidelines include 30 Key Action Statements and 27 additional recommendations derived from a comprehensive review of almost 15 000 published articles between January 2004 and July 2016. Each Key Action Statement includes level of evidence, benefit-harm relationship, and strength of recommendation. This clinical practice guideline, endorsed by the American Heart Association, is intended to foster a patient- and family-centered approach to care, reduce unnecessary and costly medical interventions, improve patient diagnoses and outcomes, support implementation, and provide direction for future research.

Neurocognitive Function in Children with Primary Hypertension

OBJECTIVE

To compare neurocognitive test performance of children with primary hypertension with that of normotensive controls.

STUDY DESIGN

Seventy-five children (10-18 years of age) with newly diagnosed, untreated hypertension and 75 frequency-matched normotensive controls had baseline neurocognitive testing as part of a prospective multicenter study of cognition in primary hypertension. Subjects completed tests of general intelligence, attention, memory, executive function, and processing speed. Parents completed rating scales of executive function and the Sleep-Related Breathing Disorder scale of the Pediatric Sleep Questionnaire (PSQ-SRBD).

RESULTS

Hypertension and control groups did not differ significantly in age, sex, maternal education, income, race, ethnicity, obesity, anxiety, depression, cholesterol, glucose, insulin, and C-reactive protein. Subjects with hypertension had greater PSQ-SRBD scores (P = .04) and triglycerides (P = .037). Multivariate analyses showed that hypertension was independently associated with worse performance on the Rey Auditory Verbal Learning Test (List A Trial 1, P = .034; List A Total, P = .009; Short delay recall, P = .013), CogState Groton Maze Learning Test delayed recall (P = .002), Grooved Pegboard dominant hand (P = .045), and Wechsler Abbreviated Scales of Intelligence Vocabulary (P = .016). Results indicated a significant interaction between disordered sleep (PSQ-SRBD score) and hypertension on ratings of executive function (P = .04), such that hypertension heightened the association between increased disordered sleep and worse executive function.

CONCLUSIONS

Youth with primary hypertension demonstrated significantly lower performance on neurocognitive testing compared with normotensive controls, in particular, on measures of memory, attention, and executive functions.

Recommendations and evidence for reporting items in pediatric clinical trial protocols and reports: two systematic reviews

BACKGROUND

Complete and transparent reporting of clinical trial protocols and reports ensures that these documents are useful to all stakeholders, that bias is minimized, and that the research is not wasted. However, current studies repeatedly conclude that pediatric trial protocols and reports are not appropriately reported. Guidelines like SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) and CONSORT (Consolidated Standards of Reporting Trials) may improve reporting, but do not offer guidance on issues unique to pediatric trials. This paper reports two systematic reviews conducted to build the evidence base for the development of pediatric reporting guideline extensions: 1) SPIRIT-Children (SPIRIT-C) for pediatric trial protocols, and 2) CONSORT-Children (CONSORT-C) for pediatric trial reports.

METHOD

MEDLINE, the Cochrane Methodology Register, and reference lists of included studies were searched. Publications of any type were eligible if they included explicit recommendations or empirical evidence for the reporting of potential items in a pediatric protocol (SPIRIT-C systematic review) or trial report (CONSORT-C systematic review). Study characteristics, recommendations and evidence for pediatric extension items were extracted. Recurrent themes in the recommendations and evidence were identified and synthesized. All steps were conducted by two reviewers.

RESULTS

For the SPIRIT-C and CONSORT-C systematic reviews 366 and 429 publications were included, respectively. Recommendations were identified for 48 of 50 original reporting items and sub-items from SPIRIT, 15 of 20 potential SPIRIT-C reporting items, all 37 original CONSORT items and sub-items, and 16 of 22 potential CONSORT-C reporting items. The following overarching themes of evidence to support or refute the utility of reporting items were identified: transparency; reproducibility; interpretability; usefulness; internal validity; external validity; reporting bias; publication bias; accountability; scientific soundness; and research ethics.

CONCLUSION

These systematic reviews are the first to systematically gather evidence and recommendations for the reporting of specific items in pediatric protocols and trials. They provide useful and translatable evidence on which to build pediatric extensions to the SPIRIT and CONSORT reporting guidelines. The resulting SPIRIT-C and CONSORT-C will provide guidance to the authors of pediatric protocols and reports, respectively, helping to alleviate concerns of inappropriate and inconsistent reporting, and reduce research waste.

Sleep disordered breathing as measured by SRBD-PSQ and neurocognition in children with hypertension

BACKGROUND

Cognitive test performance is decreased in hypertensive adults and children, a finding postulated to represent early target-organ damage to the brain. Hypertensive children are often obese, a comorbidity associated with sleep disordered breathing (SDB), itself associated with cognitive problems; potentially confounding the relation between hypertension (HTN) and neurocognition. Our objective was to determine the association between SDB as measured by a scale and questionnaire score and neurocognition among participants enrolled in an ongoing multicenter study of cognition in children with HTN.

METHODS

Subjects completed laboratory-based neurocognitive tests. Parents and subjects completed rating scales of executive function, mood, and behavior problems. Parents completed the Sleep-Related Breathing Disorder scale of the Pediatric Sleep Questionnaire (SRBD-PSQ).

RESULTS

To date, 38 HTN subjects and 34 control subjects have completed neurocognitive testing and the SRBD-PSQ. Median SRBD-PSQ scores were similar between groups but the HTN group had a higher percentage of subjects with SRBD-PSQ scores in the range suggestive of obstructive sleep apnea (26% vs. 6%, P = 0.03). Overall, higher SRBD-PSQ scores were not significantly associated with worse performance on laboratory-based measures of executive function and other cognitive domains but were significantly associated with worse scores on rating scales of executive function as well as mood and behavior problems.

CONCLUSIONS

A larger proportion of children with HTN had scores suggestive of SDB. The results underscore the importance of using a multi-method approach in the assessment of cognition and adjusting for potential confounding effects of SDB in studies of cognition in hypertensive children.

Cognitive function in hypertensive children

Young hypertensive adults demonstrate decreased performance on neurocognitive testing compared with that of normotensive controls. There is emerging, preliminary evidence that children with hypertension also manifest cognitive differences when compared to normotensive controls. These preliminary studies consist mostly of database and single-center studies that focus primarily on differences in neurocognitive test performance and differences in cerebrovascular reactivity between hypertensive and normotensive subjects. Lessons from the literature on cognition in adult hypertensives and experience from the preliminary studies in children informed the design of a current, multicenter, ongoing study of cognition in children with primary hypertension.

Screening blood pressure measurement in children: are we saving lives?

Blood Pressure screening in children and adolescents is currently recommended by several prominent medical organizations, including the American Heart Association, the National High Blood Pressure Education Program, the National Heart, Lung, and Blood Institute, the European Society of Hypertension, and the American Academy of Pediatrics. This practice was recently subject to intense scientific review by the U.S. Preventive Services Task Force. The conclusion of the Task Force was that "current evidence is insufficient to assess the balance of benefits and harms of screening for primary hypertension in asymptomatic children and adolescents." This commentary provides an alternate interpretation of current evidence for blood pressure screening in children and adolescents and highlights its importance as a part of routine medical care.