Blood pressure in children with chronic kidney disease: a report from the Chronic Kidney Disease in Children study

Blood pressure management in children on dialysis

Hypertension is a leading cause of cardiovascular complications in children on dialysis. Volume overload and activation of the renin-angiotensin-aldosterone system play a major role in the pathophysiology of hypertension. The first step in managing blood pressure (BP) is the careful assessment of ambulatory BP monitoring. Volume control is essential and should start with the accurate identification of dry weight, based on a comprehensive assessment, including bioimpedance analysis and intradialytic blood volume monitoring (BVM). Reduction of interdialytic weight gain (IDWG) is critical, as higher IDWG is associated with a worse left ventricular mass index and poorer BP control: it can be obtained by means of salt restriction, reduced fluid intake, and optimized sodium removal in dialysis. Optimization of peritoneal dialysis and intensified hemodialysis or hemodiafiltration have been shown to improve both fluid and sodium management, leading to better BP levels. Studies comparing different antihypertensive agents in children are lacking. The pharmacokinetic properties of each drug should be considered. At present, BP control remains suboptimal in many patients and efforts are needed to improve the long-term outcomes of children on dialysis.

FGF23 and Left Ventricular Hypertrophy in Children with CKD

BACKGROUND AND OBJECTIVES

High plasma concentration of fibroblast growth factor 23 (FGF23) is a risk factor for left ventricular hypertrophy (LVH) in adults with CKD, and induces myocardial hypertrophy in experimental CKD. We hypothesized that high FGF23 levels associate with a higher prevalence of LVH in children with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed echocardiograms and measured plasma C-terminal FGF23 concentrations in 587 children with mild-to-moderate CKD enrolled in the Chronic Kidney Disease in Children (CKiD) study. We used linear and logistic regression to analyze the association of plasma FGF23 with left ventricular mass index (LVMI) and LVH (LVMI ≥95th percentile), adjusted for demographics, body mass index, eGFR, and CKD-specific factors. We also examined the relationship between FGF23 and LVH by eGFR level.

RESULTS

Median age was 12 years (interquartile range, 8-15) and eGFR was 50 ml/min per 1.73 m2 (interquartile range, 38-64). Overall prevalence of LVH was 11%. After adjustment for demographics and body mass index, the odds of having LVH was higher by 2.53 (95% confidence interval, 1.28 to 4.97; P<0.01) in participants with FGF23 concentrations ≥170 RU/ml compared with those with FGF23<100 RU/ml, but this association was attenuated after full adjustment. Among participants with eGFR≥45 ml/min per 1.73 m2, the prevalence of LVH was 5.4%, 11.2%, and 15.3% for those with FGF23 <100 RU/ml, 100-169 RU/ml, and ≥170 RU/ml, respectively (Ptrend=0.01). When eGFR was ≥45 ml/min per 1.73 m2, higher FGF23 concentrations were independently associated with LVH (fully adjusted odds ratio, 3.08 in the highest versus lowest FGF23 category; 95% confidence interval, 1.02 to 9.24; P<0.05; fully adjusted odds ratio, 2.02 per doubling of FGF23; 95% confidence interval, 1.29 to 3.17; P<0.01). By contrast, in participants with eGFR<45 ml/min per 1.73 m2, FGF23 did not associate with LVH.

CONCLUSIONS

Plasma FGF23 concentration ≥170 RU/ml is an independent predictor of LVH in children with eGFR≥45 ml/min per 1.73 m2.

Survival in children requiring chronic renal replacement therapy

Survival in the pediatric end-stage renal disease (ESRD) population has improved substantially over recent decades. Nonetheless, mortality remains at least 30 times higher than that of healthy peers. Patient survival is multifactorial and dependent on various patient and treatment characteristics and degree of economic welfare of the country in which a patient is treated. In this educational review, we aim to delineate current evidence regarding mortality risk in the pediatric ESRD population and provide pediatric nephrologists with up-to-date information required to counsel affected families.

Effect of renal function on antihypertensive drug safety and efficacy in children

BACKGROUND

Hypertension and chronic kidney disease (CKD) are common comorbidities. Guidelines recommend treating hypertension in children with CKD because it is a modifiable risk factor for subsequent cardiovascular disease. Children with CKD are frequently excluded from antihypertensive drug trials. Consequently, safety and efficacy data for antihypertensive drugs are lacking in children with CKD.

METHODS

We determined the incidence of adverse events in 10 pediatric antihypertensive trials to determine the effect of renal function on antihypertensive safety and efficacy in children. These trials were submitted to the US Food and Drug Administration from 1998 to 2005. We determined the number and type of adverse events reported during the trials and compared these numbers in participants with normal renal function and those with decreased function (defined as an estimated glomerular filtration rate [eGFR] <90 mL/min/1.73 m2 calculated using the original Schwartz equation).

RESULTS

Among the 1,703 children in the 10 studies, 315 had decreased renal function. We observed no difference between the two cohorts in the incidence of adverse events or adverse drug reactions related to study drug. Only 5 participants, all with decreased renal function, experienced a serious adverse event; none was recorded by investigators to be study drug-related. Among treated participants, children with decreased renal function who received a high dose of study drug had a significantly larger drop in diastolic blood pressure compared with children with normal renal function.

CONCLUSIONS

These data show that antihypertensive treatment in children with renal dysfunction can be safe and efficacious, and consideration should be given to their inclusion in selected drug development programs.

What's new in paediatric hypertension?

Paediatric hypertension predisposes to hypertension and cardiovascular disease in adult life. Despite clear guidelines, there remains a lack of screening. Diagnosis remains challenging given the high rate of false-positive high blood pressure (BP) readings at a single visit; thus, multiple visits are required to confirm the diagnosis. Depending on the normative data sets used, hypertension in overweight and obese children can be underestimated by up to 20%. Specific BP targets are required for subgroups such as adolescents, children with chronic kidney disease (CKD) and type 1 diabetes. High dietary salt intake is a risk factor for cardiovascular disease. Given the rise in processed food consumption, children in developed nations are likely to benefit from salt restriction at a population-based level.

Waist Circumference and Body Mass Index in Children with Chronic Kidney Disease and Metabolic, Cardiovascular, and Renal Outcomes

OBJECTIVE

To describe the prevalence of obesity as estimated by waist circumference (WC) and body mass index (BMI) and compare associations of WC and BMI with indicators of metabolic, cardiovascular, and renal health in children with chronic kidney disease (CKD).

STUDY DESIGN

Cross-sectional analysis stratified by CKD etiology (nonglomerular or glomerular) of 737 subjects. The kappa statistic was used to assess agreement between the 2 measures of obesity. Linear regression models were performed using WC and BMI as separate independent variables. Dependent variables included lipid measures, insulin resistance, blood pressure, left ventricular mass index, proteinuria, and estimated glomerular filtration rate. Associations were scaled to SD and interpreted as the change in dependent variable associated with a 1-SD change in WC or BMI.

RESULTS

There was good agreement (kappa statistic = 0.68) between WC and BMI in identifying obesity. Approximately 10% of subjects had obesity by 1 measure but not the other. BMI was more strongly associated with estimated glomerular filtration rate than WC. BMI was more strongly associated with left ventricular mass index in the nonglomerular CKD group compared with WC, but both had significant associations. The associations between WC and BMI with the remainder of the dependent variables were not significantly different.

CONCLUSIONS

Measurement of WC added limited information to BMI in this cohort. Further longitudinal study is needed to determine how WC and BMI compare in predicting outcomes, particularly for children with CKD identified as having obesity by 1 measure but not the other.

Chronic kidney disease

Chronic kidney disease (CKD) is defined by persistent urine abnormalities, structural abnormalities or impaired excretory renal function suggestive of a loss of functional nephrons. The majority of patients with CKD are at risk of accelerated cardiovascular disease and death. For those who progress to end-stage renal disease, the limited accessibility to renal replacement therapy is a problem in many parts of the world. Risk factors for the development and progression of CKD include low nephron number at birth, nephron loss due to increasing age and acute or chronic kidney injuries caused by toxic exposures or diseases (for example, obesity and type 2 diabetes mellitus). The management of patients with CKD is focused on early detection or prevention, treatment of the underlying cause (if possible) to curb progression and attention to secondary processes that contribute to ongoing nephron loss. Blood pressure control, inhibition of the renin-angiotensin system and disease-specific interventions are the cornerstones of therapy. CKD complications such as anaemia, metabolic acidosis and secondary hyperparathyroidism affect cardiovascular health and quality of life, and require diagnosis and treatment.

Racial variation in cardiovascular disease risk factors among European children on renal replacement therapy-results from the European Society for Paediatric Nephrology/European Renal Association - European Dialysis and Transplant Association Registry

Background

Racial differences in overall mortality rates have been found in children on renal replacement therapy (RRT). We used data from the European Society for Paediatric Nephrology/European Renal Association - European Dialysis and Transplant Association Registry to study racial variation in the prevalence of cardiovascular disease (CVD) risk factors among European children on RRT.

Methods

We included patients aged <20 years between 2006-13 who (i) initiated dialysis treatment or (ii) had a renal transplant vintage of ≥1 year. Racial groups were defined as white, black, Asian and other. The CVD risk factors assessed included uncontrolled hypertension, obesity, hyperphosphataemia and anaemia. Differences between racial groups in CVD risk factors were examined using generalized estimating equation (GEE) models while adjusting for potential confounders.

Results

In this study, 1161 patients on dialysis and 1663 patients with a transplant were included. The majority of patients in both groups were white (73.8% and 79.9%, respectively). The crude prevalence of the CVD risk factors was similar across racial groups. However, after adjustment for potential confounders, Asian background was associated with higher risk of uncontrolled hypertension both in the dialysis group [odds ratio (OR): 1.27; 95% confidence interval (CI): 1.01-1.64] and the transplant group (OR: 1.37; 95% CI: 1.11-1.68) compared with white patients. Patients of Asian and other racial background with a renal transplant had a higher risk of anaemia compared with white patients (OR: 1.50; 95% CI: 1.15-1.96 and OR: 1.45; 95% CI: 1.01-2.07, respectively). Finally, the mean number of CVD risk factors among dialysis patients was higher in Asian patients (1.83, 95% CI: 1.64-2.04) compared with white patients (1.52, 95% CI: 1.40-1.65).

Conclusions

We found a higher prevalence of modifiable CVD risk factors in Asian children on RRT. Early identification and management of these risk factors could potentially improve long-term outcomes.

Evaluation of the coronary circulation and calcification in children on regular hemodialysis

BACKGROUND

The objective of this study was to evaluate the coronary circulation and calcification in children with end-stage renal disease (ESRD) on hemodialysis.

METHODS

A total of 50 children with ESRD and 50 healthy controls were enrolled in the study. Cardiac functions and coronary blood flow were evaluated with conventional and tissue Doppler echocardiography. Coronary artery calcification (CAC) was evaluated using high-resolution multidetector computed tomography (CT).

RESULTS

The hyperemic coronary flow volume (CFV) and coronary flow reserve were significantly lower in the patient group than in the controls, while there was no significant difference in the baseline CFV between the two groups. Hypertension was present in 60% and CAC was observed in 20% of the children in the patient group. CAC was present in 30% of the children in the hypertensive subgroup. The left ventricle myocardial performance index (LV MPI), CAC score, duration of hypertension and level of diastolic blood pressure were independent predictors of the coronary blood flow, and LV MPI, serum parathyroid hormone, duration of dialysis and E'/A' mitral valve were independent predictors of coronary calcification.

CONCLUSION

High diastolic blood pressure, long duration of hypertension, high LV MPI and increased CAC scores are independent risk factors for impaired coronary blood flow in children with ESRD.

2016 European Society of Hypertension guidelines for the management of high blood pressure in children and adolescents

Increasing prevalence of hypertension (HTN) in children and adolescents has become a significant public health issue driving a considerable amount of research. Aspects discussed in this document include advances in the definition of HTN in 16 year or older, clinical significance of isolated systolic HTN in youth, the importance of out of office and central blood pressure measurement, new risk factors for HTN, methods to assess vascular phenotypes, clustering of cardiovascular risk factors and treatment strategies among others. The recommendations of the present document synthesize a considerable amount of scientific data and clinical experience and represent the best clinical wisdom upon which physicians, nurses and families should base their decisions. In addition, as they call attention to the burden of HTN in children and adolescents, and its contribution to the current epidemic of cardiovascular disease, these guidelines should encourage public policy makers to develop a global effort to improve identification and treatment of high blood pressure among children and adolescents.

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.

Hypertension in pediatric patients with chronic kidney disease: management challenges

In contrast to adults where hypertension is a leading cause of chronic kidney disease, in pediatrics, hypertension is predominantly a sequela, however, an important one that, like in adults, is likely associated with a more rapid decline in kidney function or progression of chronic kidney disease to end stage. There is a significant issue with unrecognized, or masked, hypertension in childhood chronic kidney disease. Recent evidence and, therefore, guidelines now suggest targeting a blood pressure of <50th percentile for age, sex, and height in children with proteinuria and chronic kidney disease. This often cannot be achieved by monotherapy and additional agents need to be added. Blockade of the renin angiotensin aldosterone system represents the mainstay of therapy, although often limited by the side effect of hyperkalemia. The addition of a diuretic, at least in the earlier stages of chronic kidney disease, might help mitigate this problem.

Albuminuria, Proteinuria, and Renal Disease Progression in Children with CKD

BACKGROUND AND OBJECTIVES

The role of albuminuria as an indicator of progression has not been investigated in children with CKD in the absence of diabetes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Children were enrolled from 49 centers of the CKD in Children study between January of 2005 and March of 2014. Cross-sectional multivariable linear regression (n=647) was used to examine the relationship between urine protein-to-creatinine (UP/C [milligrams per milligram]) and albumin-to-creatinine (ACR [milligrams per gram]) with eGFR (milliliters per minute per 1.73 m2). Parametric time-to-event analysis (n=751) was used to assess the association of UP/C, ACR, and urine nonalbumin-to-creatinine (Unon-alb/cr [milligrams per gram]) on the time to the composite endpoint of initiation of RRT or 50% decline in eGFR.

RESULTS

The median follow-up time was 3.4 years and 202 individuals experienced the event. Participants with a UP/C≥0.2 mg/mg and ACR≥30 mg/g had a mean eGFR that was 16 ml/min per 1.73 m2 lower than those with a UP/C<0.2 mg/mg and ACR<30 mg/g. Individuals with ACR<30 mg/g, but a UP/C≥0.2 mg/mg, had a mean eGFR that was 9.3 ml/min per 1.73 m2 lower than those with a UP/C<0.2 mg/mg and ACR<30 mg/g. When categories of ACR and Unon-alb/cr were created on the basis of clinically meaningful cutoff values of UP/C with the same sample sizes for comparison, the relative times (RTs) to the composite end-point were almost identical when comparing the middle (RT=0.31 for UP/C [0.2-2.0 mg/mg], RT=0.38 for ACR [56-1333 mg/g], RT=0.31 for Unon-alb/cr [118-715 mg/g]) and the highest (RT=0.08 for UP/C [>2.0 mg/mg], RT=0.09 for ACR [>1333 mg/g], RT=0.07 for Unon-alb/cr [>715 mg/g]) levels to the lowest levels. A similar trend was seen when categories were created on the basis of clinically meaningful cutoff values of ACR (<30, 30-300, >300 mg/g).

CONCLUSIONS

In children with CKD without diabetes, the utility of an initial UP/C, ACR, and Unon-alb/cr for characterizing progression is similar.

Vascular Stiffness in Children With Chronic Kidney Disease

Carotid-femoral pulse wave velocity (cfPWV) is a measure of arterial stiffness associated with cardiovascular events in the general population and in adults with chronic kidney disease. However, few data exist regarding cfPWV in children with chronic kidney disease. We compared observed cfPWV assessed via applanation tonometry in children enrolled in the CKiD cohort study (Chronic Kidney Disease in Children) to normative data in healthy children and examined risk factors associated with elevated cfPWV. cfPWV Z score for height/gender and age/gender was calculated from and compared with published pediatric norms. Multivariable linear regression was used to assess the relationship between cfPWV and age, gender, race, body mass index, diagnosis, urine protein-creatinine ratio, mean arterial pressure, heart rate, number of antihypertensive medications, uric acid, and serum low-density lipoprotein. Of the 95 participants with measured cfPWV, 60% were male, 19% were black, 46% had glomerular cause of chronic kidney disease, 22% had urine protein-creatinine ratio 0.5 to 2.0 mg/mg and 9% had >2.0 mg/mg, mean age was 15.1 years, average mean arterial pressure was 80 mm Hg, and median glomerular filtration rate was 63 mL/min per 1.73 m² Mean cfPWV was 5.0 m/s (SD, 0.8 m/s); mean cfPWV Z score by height/gender norms was -0.1 (SD, 1.1). cfPWV increased significantly with age, mean arterial pressure, and black race in multivariable analysis; no other variables, including glomerular filtration rate, were independently associated with cfPWV. In this pediatric cohort with mild kidney dysfunction, arterial stiffness was comparable to that of normal children. Future research is needed to examine the impact of chronic kidney disease progression on arterial stiffness and associated cardiovascular parameters in children.

Renin-angiotensin II-aldosterone system blockers and time to renal replacement therapy in children with CKD

BACKGROUND

Clinical care decisions to treat chronic kidney disease (CKD) in a growing child must often be made without the benefit of evidence from clinical trials. We used observational data from the Chronic Kidney Disease in Children cohort to estimate the effectiveness of renin-angiotensin II-aldosterone system blockade (RAAS) to delay renal replacement therapy (RRT) in children with CKD.

METHODS

A total of 851 participants (median age: 11 years, median glomerular filtration rate [GFR]: 52 ml/min/1.73 m2, median urine protein to creatinine ratio: 0.35 mg/mg) were included. RAAS use was reported at annual study visits. Both Cox proportional hazards models with time-varying RAAS exposure and Cox marginal structural models (MSM) were used to evaluate the effect of RAAS use on time to RRT. Analyses were adjusted or weighted to control for age, male sex, glomerular diagnosis, GFR, nephrotic range proteinuria, anemia, elevated blood pressure, acidosis, elevated phosphate and elevated potassium.

RESULTS

There were 217 RRT events over a 4.1-year median follow-up. At baseline, 472 children (55 %) were prevalent RAAS users, who were more likely to be older, have a glomerular etiology, have higher urine protein, be anemic, have elevated serum phosphate and potassium, take more medications, but less likely to have elevated blood pressure, compared with non-users. RAAS use was found to reduce the risk of RRT by 21 % (hazard ratio: 0.79) to 37 % (hazard ratio: 0.63) from standard regression adjustment and MSM models, respectively.

CONCLUSIONS

These results support inferences from adult studies of a substantial benefit of RAAS use in pediatric CKD patients.

Hypertension in the Pediatric Kidney Transplant Recipient

Hypertension after kidney transplant is a frequent occurrence in pediatric patients. It is a risk factor for graft loss and contributes to the significant burden of cardiovascular disease (CVD) in this population. The etiology of posttransplant hypertension is multifactorial including donor factors, recipient factors, medications, and lifestyle factors similar to those prevalent in the general population. Ambulatory blood pressure monitoring has emerged as the most reliable method for measuring hypertension in pediatric transplant recipients, and many consider it to be essential in the care of these patients. Recent technological advances including measurement of carotid intima-media thickness, pulse wave velocity, and myocardial strain using specked echocardiography and cardiac magnetic resonance imaging have improved our ability to assess CVD burden. Since hypertension remains underrecognized and inadequately treated, an early diagnosis and an appropriate control should be the focus of therapy to help improve patient and graft survival.

What has changed in the prevalence of hypertension in dialyzed children during the last decade?

BACKGROUND

Hypertension very often accompanies progression of chronic kidney disease (CKD) in children. A cross-sectional analysis of hypertension prevalence in dialyzed children in Poland was designed with a comparison with the data previously recorded 10 years earlier.

METHODS

Two cohorts of children were analyzed: 59 subjects dialyzed in 2013, and 134 children from the previous study performed in 2003 that were reevaluated according to the current methodology. The incidence of hypertension (defined by SDS of sBP or dBP >1.64), clinical data, medical history, dialysis modalities and selected biochemical parameters of dialysis adequacy were analyzed.

RESULTS

The prevalence of hypertension increased from 64% in 2003 to 78% in 2013. The efficacy of antihypertensive treatment remained unsatisfactory (61% proper BP control). Preservation of residual urine output and strict fluid balance may prevent development of hypertension in children on dialysis.

CONCLUSIONS

Despite the higher awareness of hypertension and its complications in dialyzed children, the incidence of this entity has increased during the last decade, with the percentage of undertreated patients comparable to that observed 10 years ago. Thus, more attention should be paid to therapy efficacy in this population to prevent further damage to the cardiovascular system and to decrease morbidity.

Cardiovascular Disease Risk Factors and Left Ventricular Hypertrophy in Girls and Boys With CKD

BACKGROUND AND OBJECTIVES

Prior studies suggested that women with CKD have higher risk for cardiovascular disease (CVD) and mortality than men, although putative mechanisms for this higher risk have not been identified. We assessed sex differences in (1) CVD risk factors and left ventricular hypertrophy (LVH), and (2) the relationship of left ventricular mass (LVM) with different measures of body size in children with CKD.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

The study population comprised 681 children with CKD from the Chronic Kidney Disease in Children cohort, contributing 1330 visits. CVD risk factors were compared cross-sectionally by sex. LVH was defined as LVM/height2.7 >95th percentile and LVM relative to estimated lean body mass (eLBM) >95th percentile for age and sex. Differences in LVM by sex were assessed by adjusting for age, weight, height, and eLBM using bivariate and multivariate regression models.

RESULTS

Girls were less likely to have uncontrolled hypertension (26% versus 38%, P=0.001), had lower diastolic BP z-scores (+0.3 versus +0.6, P=0.001), and had lower prevalence of high triglycerides (38% versus 47%, P=0.03) compared with boys. When LVH was defined by LVM indexed to height, girls had higher prevalence of LVH (16% versus 9%, P=0.01); when LVH was defined by LVM relative to eLBM, prevalence of LVH was similar between girls and boys (18% versus 17%, P=0.92). In regression models adjusting for eLBM, no sex differences in LVM were observed.

CONCLUSIONS

Despite lack of increased prevalence of CVD risk factors, indexing LVM to height showed a higher proportion of LVH among girls, while estimates of LVH based on eLBM showed no sex differences. Indexing LVM to eLBM may be an alternative to height indexing in children with CKD.

Association of blood pressure variability and neurocognition in children with chronic kidney disease

BACKGROUND

Children with chronic kidney disease (CKD) and hypertension have increased blood pressure variability (BPV), which has been associated with lower neurocognitive test scores in adults. Children with CKD are at risk for decreased neurocognitive function. Our objective was to determine whether children with CKD and increased BPV had worse performance on neurocognitive testing compared with children with CKD and lower BPV.

METHODS

This was a cross-sectional and longitudinal analysis of the relation between BPV and neurocognitive test performance in children ≥6 years enrolled in the Chronic Kidney Disease in Children (CKiD) study. Visit-to-visit BPV was assessed by the standard deviation of visit BPs (BPV-SD) and average real variability (ARV). Ambulatory BPV was assessed by SD of wake and sleep periods on 24-h ambulatory BP monitoring.

RESULTS

We assessed 650 children with a mean follow-up period of 4.0 years. Children with systolic visit-to-visit BPV in the upper tertile had lower scores on Delis-Kaplan Executive Function System (D-KEFS) Verbal Category Switching than those with BPV in the lower tertile (BPV-SD, 8.3 vs. 9.5, p = 0.006; ARV, 8.5 vs. 9.6, p = 0.02). On multivariate analysis, the association between lower Category Switching score and increased BPV remained significant after controlling for mean BP, demographic characteristics, and disease-related variables [BPV-SD, β = -0.7, 95 % confidence interval (CI) -1.28 to -0.12; ARV, β = -0.54, CI -1.05 to -0.02). Ambulatory BPV was not independently associated with any cognitive measure.

CONCLUSIONS

Higher systolic visit-to-visit BPV was independently associated with decreased D-KEFS Category Switching scores in children with mild-to-moderate CKD.

Racial differences in renal replacement therapy initiation among children with a nonglomerular cause of chronic kidney disease

PURPOSE

African American (AA) adults with chronic kidney disease (CKD) have a faster progression to end-stage renal disease and are less likely to receive a kidney transplant. It is unclear whether AA children experience renal replacement therapy (RRT) for end-stage renal disease sooner than non-AA children after accounting for socioeconomic status (SES).

METHODS

Among children with nonglomerular CKD in the Chronic Kidney Disease in Children study, we investigated time to RRT (i.e., first dialysis or transplant) after CKD onset using parametric survival models and accounted for SES differences by inverse probability weights.

RESULTS

Of 110 AA and 493 non-AA children (median age = 10 years), AA children had shorter time to first RRT: median time was 3.2 years earlier than non-AA children (95% CI: -6.1, -0.3). When accounting for SES, this difference was diminished and nonsignificant (-1.6 years; 95% CI: -4.6, +1.5), and its directionality was consistent with faster glomerular filtration rate decline among AA children (-6.2% vs. -4.4% per year, P = .098). When RRT was deconstructed into dialysis or transplant, the time to dialysis was 37.5% shorter for AA children and 53.7% longer for transplant. These inferences were confirmed by the frequency and timing of transplant after initiating dialysis.

CONCLUSIONS

Racial differences in time to RRT were almost fully accounted for by SES, and the remaining difference was congruent with a faster glomerular filtration rate decline among AA children. Access to transplant occurred later, yet times to dialysis were shorter among AA children even when accounting for SES which may be due to a lack of organ availability.

Childhood Albuminuria and Chronic Kidney Disease is Associated with Mortality and End-Stage Renal Disease

BACKGROUND

We do not yet fully grasp the significance of childhood albuminuria. Based on mass urinary screening (MUS) using albumin-specific dipsticks in school children, we studied the independent association of estimated glomerular filtration rate (eGFR) and albuminuria with mortality and end-stage renal disease (ESRD) in children with chronic kidney disease (CKD).

METHODS

A prospective cohort of 5351 children with albuminuria detected by school MSU during the period 1992-1996, followed up to 2009.

RESULTS

Cumulative mortality rate, prevalence of CKD, and ESRD were higher in children with albuminuria than those without. Albuminuria category was associated with the risk of mortality [hazard ratio (HR) 3.4] and ESRD (HR 3.24). Lower eGFR and albuminuria predicted mortality and ESRD among children with albuminuria and CKD. We found that being below a threshold of 45 mL/min/1.73 m(2) was significantly associated with ESRD. The highest renal function decline, along with the steepest slope of cumulative ESRD number, occurred in Stage 3, the critical point in renal progression. Risk factors for renal progression among different age groups with albuminuria were hypercholesterolemia and low serum albumin at 7-17 years of age. Beyond 18 years of age, besides the risk factor, a higher fasting blood sugar (BS) was also noted.

CONCLUSION

Childhood albuminuria is a risk factor for CKD in later life, albuminuria provides additional prognostic information, and complications of CKD should be defined in each case.

Effect of elevated blood pressure on quality of life in children with chronic kidney disease

BACKGROUND

Although hypertension is known to have an adverse impact on health-related quality of life (HRQoL) in adults, little is known about the effects of hypertension and use of antihypertensive medications on HRQoL in hypertensive children with chronic kidney disease (CKD).

METHODS

Cross-sectional and longitudinal assessment of impact of elevated blood pressure (BP) and antihypertensive medication use on HRQoL scores obtained in children enrolled in the Chronic Kidney Disease in Children (CKiD) Study. Blood pressure was measured both manually and by ambulatory blood pressure monitoring. HRQoL was assessed with the PedsQL survey.

RESULTS

The study sample included 551 participants with sufficient data for cross-sectional and longitudinal analyses. Cross-sectional analysis of presence of prehypertension or hypertension and impact on HRQoL found mild associations between elevated BP and HRQoL scores with overall PedsQL parent and child scores averaging 79 vs. 76.5 and 83 vs. 78.5, respectively. However, no associations persisted under longitudinal multivariate analysis.

CONCLUSIONS

Despite apparent small effects of elevated BP on HRQoL at baseline, no association was found between the presence of elevated BP and HRQoL over time in children with mild-to-moderate CKD. In addition, antihypertensive medication use did not appear to have an impact on HRQoL in this population.

Clinical characteristics and prevalence of complications of chronic kidney disease in children: the Taiwan Pediatric Renal Collaborative study

BACKGROUND

Little information is available regarding the clinical characteristics and prevalence of complications in children with chronic kidney disease (CKD), especially in early disease stages. The objective of this study was to determine the clinical characteristics and prevalence of complications in children with predialytic CKD.

METHODS

This multicenter, cross-sectional study enrolled children at all stages of predialytic CKD. Children who were between the ages of 1 year and 18 years and who fulfilled the clinical criteria of CKD were included in the study. Baseline demographic data, previous history, clinical characteristics, and laboratory data were collected.

RESULTS

A total of 757 children were included in the study. The median age at the time of enrollment was 10.6 years; 397 patients (52.4 %) were males. A total of 39.0 % of the patients were in CKD stage 1, 37.6 % were in stage 2, 14.8 % were in stage 3, 3.0 % were in stage 4, and 5.5 % were in stage 5. Nonglomerular renal diseases were the primary cause of CKD, comprising 51.9 % of the patients with CKD. The age at disease onset, gender, CKD stage distribution, and proportion of co-morbidities varied between the glomerular and nonglomerular CKD cases. Anemia, hyperlipidemia, hypocalcemia, and hyperphosphatemia were more prevalent in patients with glomerular CKD. The overall prevalence of complications was as follows: uncontrolled blood pressure, 44.1 %; anemia, 34.2 %; hyperlipidemia, 44.9 %; short stature, 10.3 %; and failure to thrive, 8.2 %. Uncontrolled blood pressure (BP), anemia, and hyperlipidemia were common, even in the early CKD stages. The prevalence of CKD complications generally increased with the worsening stage of CKD.

CONCLUSIONS

This study reveals differences in CKD etiology and prevalence of specific complications according to the stage of CKD. Early recognition and awareness of complications are mandatory for clinicians during the follow-up visits of children with CKD.

Chronic kidney disease in children

Chronic kidney disease (CKD) is a major health problem worldwide. Although relatively uncommon in children, it can be a devastating illness with many long-term consequences. CKD presents unique features in childhood and may be considered, at least in part, as a stand-alone nosologic entity. Moreover, some typical features of paediatric CKD, such as the disease aetiology or cardiovascular complications, will not only influence the child's health, but also have long-term impact on the life of the adult that they will become. In this review we will focus on the unique issues of paediatric CKD, in terms of aetiology, clinical features and treatment. In addition, we will discuss factors related to CKD that start during childhood and require appropriate treatments in order to optimize health outcomes and transition to nephrologist management in adult life.

PROGRESSION OF CHRONIC KIDNEY DISEASE AFTER ACUTE KIDNEY INJURY

The incidence of chronic kidney disease (CKD) in children and adults is increasing. Cardiologists have become indispensable members of the care provider team for children with CKD. This is partly due to the high incidence of CKD in children and adults with congenital heart disease, with current estimates of 30-50%. In addition, the high incidence of acute kidney injury (AKI) due to cardiac dysfunction or following pediatric cardiac surgery that may progress to CKD is also well documented. It is now apparent that AKI and CKD are uniquely intertwined as interconnected syndromes. Furthermore, the well-known long-term cardiovascular morbidity and mortality associated with CKD require the joint attention of both nephrologists and cardiologists. Children with both congenital heart disease and CKD are increasingly surviving to adulthood, with synergistically negative medical, financial, and quality of life impact. An improved understanding of the epidemiology, mechanisms, early diagnosis, and preventive measures is of importance to cardiologists, nephrologists, scientists, economists, and policy makers alike. Herein, we report the current definitions, epidemiology, and complications of CKD in children, with an emphasis on children with congenital heart disease. We then focus on the clinical and experimental evidence for the progression of CKD after episodes of AKI commonly encountered in children with heart disease, and explore the role of novel biomarkers for the prediction of CKD progression.

Hypertension in chronic kidney disease: role of ambulatory blood pressure monitoring

Children with chronic kidney disease have a markedly increased risk of cardiovascular morbidity and children with end stage renal disease have an estimated 30 times greater risk of cardiovascular mortality than the general pediatric population. In adults, the link between hypertension and cardiovascular disease is well-documented but that association has not been so readily apparent in children with chronic kidney disease. This may be in part because the early changes in blood pressure that occur in these patients do not necessarily manifest with changes in casual blood pressure measurements. Ambulatory blood pressure monitoring, with its ability to gather multiple readings both during the normal activities of the day and the night, is felt to be a more veritable measure of blood pressure. Its use in children has been hampered by limited data on normative values and difficulties in blood pressure classification, while its use in adults is ever expanding. However, with an increasing number of studies in children with chronic kidney disease, ambulatory blood pressure has revealed a greater prevalence of abnormal findings in this population and has been shown to better predict cardiovascular risk than current standards. Two large multi-center studies in Europe and North America have revealed even greater utility of ambulatory blood pressure measures in this population. It is hoped that continued use of ambulatory monitoring in children will help overcome some of its perceived limitations while also validating its use in those at high risk of cardiovascular morbidity.

Pharmacologic Management of Pediatric Hypertension

Hypertension in children is common, and the prevalence of primary hypertension is increasing with the obesity epidemic and changing dietary choices. Careful measurement of blood pressure is important to correctly diagnose hypertension, as many factors can lead to inaccurate blood pressure measurement. Hypertension is diagnosed based on comparison of age-, sex-, and height-based norms with the average systolic and diastolic blood pressures on three separate occasions. In the absence of hypertensive target organ damage (TOD), stage I hypertension is managed first by diet and exercise, with the addition of drug therapy if this fails. First-line treatment of stage I hypertension with TOD and stage II hypertension includes both lifestyle changes and medications. First-line agents include angiotensin-converting enzyme (ACE) inhibitors, thiazide diuretics, and calcium-channel blockers. Hypertensive emergency with end-organ effects requires immediate modest blood pressure reduction to alleviate symptoms. This is usually accomplished with IV medications. Long-term reduction in blood pressure to normal levels is accomplished gradually. Specific medication choice for outpatient hypertension management is determined by the underlying cause of hypertension and the comparative adverse effect profiles, along with practical considerations such as cost and frequency of administration. Antihypertensive medication is initiated at a starting dose and can be gradually increased to effect. If ineffective at the recommended maximum dose, an additional medication with a complementary mechanism of action can be added.

Cardiovascular alterations do exist in children with stage-2 chronic kidney disease

BACKGROUND

Cardiovascular disease (CVD) is an important complication of chronic kidney disease (CKD) in children. However, it is not well known when and how cardiovascular alterations start.

METHODS

This cross-sectional, controlled study consisted of 25 patients and 28 healthy controls. 24-h ambulatory blood pressure monitoring, aortic pulse wave velocity (aPWV), carotid intima-media thickness (cIMT) and carotid distensibility (distensibility coefficient and β stiffness index), and echocardiography were assessed to evaluate CVD. Routine biochemical parameters, fibroblast growth factor-23 (FGF23) and high sensitive C- reactive protein were measured to determine cardiovascular risk factors.

RESULTS

Hypertension was found in 12 patients (48 %). Patients had higher FGF23 levels and aPWV-standard deviation score (SDS) as compared to the controls (p = 0.003 and p = 0.002, respectively). Aortic PWV-SDS was predicted by increased daytime systolic blood pressure load (β = 0.512, p = 0.009, R ² = 0.262). Neither cIMT nor distensibility differed between the groups; however, older age and high level of FGF23 were independent predictors of β stiffness index in patients (β = 0.507, p = 0.005, R ² = 0.461 and β = 0.502, p = 0.005, R ² = 0.461, respectively). As compared to controls, patients had worse left ventricular diastolic function [lower E/A ratio p = 0.006) and increased left atrial dimension (p < 0.001)].

CONCLUSIONS

Cardiovascular deteriorations appear in children with stage-2 CKD. Good control of BP and decreasing the level of FGF23 may be useful to slow down the progression of cardiovascular complications.

Can office blood pressure readings predict masked hypertension?

BACKGROUND

Studies in children with chronic kidney disease indicate a high prevalence of masked hypertension detected by ambulatory blood pressure monitoring (ABPM). However, it is not well known if the frequency of masked hypertension is related to the level of normal casual blood pressure (BP).

METHODS/RESULTS

We hypothesized that lower levels of normal casual BP are associated with a lower prevalence of masked hypertension. Data from the chronic kidney disease (CKiD) cohort were analyzed cross-sectionally across multiple visits. The majority of children with normal casual BP also had normal wake and sleep ABP (60 %), even at the highest percentiles of casual BP. The frequency of masked hypertension was lower in children with casual BP ≤25th percentile versus those with casual BP in 26-50th percentile and casual BP in 51-90th percentile during both wake and sleep periods. In children with the lowest normal casual BP levels (≤25th percentile), the frequency of abnormal mean wake or sleep ABP was 2-7 %, and of abnormal BP load was 6-16 %.

CONCLUSIONS

These data suggest that masked hypertension is unlikely if the casual BP is found to be in the low normal range.

Renal and Cardiovascular Morbidities Associated with APOL1 Status among African-American and Non-African-American Children with Focal Segmental Glomerulosclerosis

BACKGROUND AND OBJECTIVES

African-American (AA) children with focal segmental glomerulosclerosis (FSGS) have later onset disease that progresses more rapidly than in non-AA children. It is unclear how APOL1 genotypes contribute to kidney disease risk, progression, and cardiovascular morbidity in children.

DESIGN SETTING PARTICIPANTS AND MEASUREMENTS

We examined the prevalence of APOL1 genotypes and associated cardiovascular phenotypes among children with FSGS in the Chronic Kidney Disease in Children (CKiD) study; an ongoing multicenter prospective cohort study of children aged 1-16 years with mild to moderate kidney disease.

RESULTS

A total of 140 AA children in the CKiD study were genotyped. High risk (HR) APOL1 genotypes were present in 24% of AA children (33/140) and were associated with FSGS, p < 0.001. FSGS was the most common cause of glomerular disease in children with HR APOL1 (89%; 25/28). Of 32 AA children with FSGS, 25 (78%) had HR APOL1. Compared to children with low risk APOL1 and FSGS (comprising 36 non-AA and 7 AA), children with HR APOL1 developed FSGS at a later age, 12.0 (IQR: 9.5, 12.5) vs. 5.5 (2.5, 11.5) years, p = 0.004, had a higher prevalence of uncontrolled hypertension (52 vs. 33%, p = 0.13), left ventricular hypertrophy (LVH) (53 vs. 12%, p < 0.01), C-reactive protein > 3 mg/l (33 vs. 15%, p = 0.12), and obesity (48 vs. 19%, p = 0.01). There were no differences in glomerular filtration rate, hemoglobin, iPTH, or calcium-phosphate product.

CONCLUSION

AA children with HR APOL1 genotype and FSGS have increase prevalence of obesity and LVH despite a later age of FSGS onset, while adjusting for socioeconomic status. Treatment of obesity may be an important component of chronic kidney disease and LVH management in this population.

Role of 24-h ambulatory blood pressure monitoring in children with chronic kidney disease

Hypertension is common in children with chronic kidney disease (CKD) and is a major determinant of CKD progression. Ambulatory blood pressure monitoring (ABPM) has been proposed to be better in detecting hypertension as compared to casual blood pressure (CBP). This study aims to study the usefulness of ABPM in detecting masked hypertension, evaluating the adequacy of blood pressure (BP) control and predicting left ventricular hypertrophy (LVH) amongst children with CKD. A prospective cross-sectional study of 46 children with stage 3–5 CKD was conducted at the Pediatric Nephrology department of a tertiary hospital in South India. All children underwent CBP, ABPM and an echocardiography. Results were categorized as normal BP; confirmed hypertension; masked hypertension and white coat hypertension. Out of 46 children studied, 11 were undergoing dialysis. While 39.1% children had stage 3 and 4 CKD each, 21.7% had stage 5 CKD. Masked hypertension was detected in 19.6% and 21.7% had confirmed hypertension. Thirty-four (73.9%) children were already receiving antihypertensive medication. In these, CBP was elevated in 23.5% and ABP in 47%. Among children with hypertension as defined by ABPM, LVH was detected in 32.2%. We found that higher the number of abnormal ABPM indices (assessed by BP Index, nocturnal dipping and BP Load) higher the likelihood of LVH (P = 0.046). ABPM is better in detecting hypertension and monitoring adequacy of treatment in children with CKD. The high prevalence of masked hypertension and its association with LVH supports early echocardiography and ambulatory BP monitoring to evaluate cardiovascular risks in this population.

Chronic Kidney Disease in Children: Recent Update

The incidence of end stage of renal disease (ESRD) in US children age 0-19 years is 12.9 per million/year (2012). The economic and social burden of diagnosing, treating and preventing chronic kidney disease (CKD) in children and adults remains substantial. Advances in identifying factors that predict development of CKD and its progression, as well as advances in the management of co-morbid conditions including anemia, cardiovascular disease, growth, mineral and bone disorder, and neurocognitive function are discussed. Despite recent reports from retrospective registry data analysis and multi-center prospective studies which have significantly advanced our knowledge of CKD, and despite advances in the understanding of the pathogenesis, diagnosis and treatment of CKD much work remains to be done to improve the long term outcome of this disease.

Pre-treatment considerations in childhood hypertension due to chronic kidney disease

Hypertension (HTN) develops very early in childhood chronic kidney disease (CKD). It is linked with rapid progression of kidney disease, increased morbidity and mortality hence the imperative to start anti-hypertensive medication when blood pressure (BP) is persistently > 90^th percentile for age, gender, and height in non-dialyzing hypertensive children with CKD. HTN pathomechanism in CKD is multifactorial and complexly interwoven. The patient with CKD-associated HTN needs to be carefully evaluated for co-morbidities that frequently alter the course of the disease as successful treatment of HTN in CKD goes beyond life style modification and anti-hypertensive therapy alone. Chronic anaemia, volume overload, endothelial dysfunction, arterial media calcification, and metabolic derangements like secondary hyperparathyroidism, hyperphosphataemia, and calcitriol deficiency are a few co-morbidities that may cause or worsen HTN in CKD. It is important to know if the HTN is caused or made worse by the toxic effects of medications like erythropoietin, cyclosporine, tacrolimus, corticosteroids and non-steroidal anti-inflammatory drugs. Poor treatment response may be due to any of these co-morbidities and medications. A satisfactory hypertensive CKD outcome, therefore, depends very much on identifying and managing these co-morbid conditions and HTN promoting medications promptly and appropriately. This review attempts to point attention to factors that may affect successful treatment of the hypertensive CKD child and how to attain the desired therapeutic BP target.

Treatment of hypertension in children with chronic kidney disease

Hypertension (HTN) is increasingly recognized as a common feature of pediatric chronic kidney disease (CKD). A growing body of evidence demonstrates that HTN is both underdiagnosed and undertreated in this population. The consequences of untreated HTN include adverse effects on CKD progression, markers of cardiovascular morbidity, and neurocognitive functioning. Consensus guidelines issued over the past decade have incorporated recent research on the consequences of HTN in recommendations for the diagnosis and treatment of HTN in pediatric CKD and include lower BP targets. Agents which target the renin-angiotensin-aldosterone system (RAAS) should be considered first-line therapy in CKD-associated HTN in children, though multiple medications may be required to achieve sufficient BP control.

Predictors of Rapid Progression of Glomerular and Nonglomerular Kidney Disease in Children and Adolescents: The Chronic Kidney Disease in Children (CKiD) Cohort

BACKGROUND

Few studies have prospectively evaluated the progression of chronic kidney disease (CKD) in children and adolescents, as well as factors associated with progression.

STUDY DESIGN

Prospective multicenter observational cohort study.

SETTING & PARTICIPANTS

496 children and adolescents with CKD enrolled in the Chronic Kidney Disease in Children (CKiD) Study.

PREDICTORS

Proteinuria, hypoalbuminemia, blood pressure, dyslipidemia, and anemia.

OUTCOMES

Parametric failure-time models were used to characterize adjusted associations between baseline levels and changes in predictors and time to a composite event of renal replacement therapy or 50% decline in glomerular filtration rate (GFR).

RESULTS

398 patients had nonglomerular disease and 98 had glomerular disease; of these, 29% and 41%, respectively, progressed to the composite event after median follow-ups of 5.2 and 3.7 years, respectively. Demographic and clinical characteristics and outcomes differed substantially according to the underlying diagnosis; hence, risk factors for progression were assessed in stratified analyses, and formal interactions by diagnosis were performed. Among patients with nonglomerular disease and after adjusting for baseline GFR, times to the composite event were significantly shorter with urinary protein-creatinine ratio > 2mg/mg, hypoalbuminemia, elevated blood pressure, dyslipidemia, male sex, and anemia, by 79%, 69%, 38%, 40%, 38%, and 45%, respectively. Among patients with glomerular disease, urinary protein-creatinine ratio >2mg/mg, hypoalbuminemia, and elevated blood pressure were associated with significantly reduced times to the composite event by 94%, 71%, and 67%, respectively. Variables expressing change in patient clinical status over the initial year of the study contributed significantly to the model, which was cross-validated internally.

LIMITATIONS

Small number of events in glomerular patients and use of internal cross-validation.

CONCLUSIONS

Characterization and modeling of risk factors for CKD progression can be used to predict the extent to which these factors, either alone or in combination, would shorten the time to renal replacement therapy or 50% decline in GFR in children with CKD.

Progression of pediatric CKD of nonglomerular origin in the CKiD cohort

BACKGROUND AND OBJECTIVES

Congenital anomalies of the kidney and urinary tract and genetic disorders cause most cases of CKD in children. This study evaluated the relationships between baseline proteinuria and BP and longitudinal changes in GFR in children with these nonglomerular causes of CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Urine protein-to-creatinine ratio, casual systolic and diastolic BP (normalized for age, sex, and height), and GFR decline were assessed in the prospective CKD in Children cohort study.

RESULTS

A total of 522 children, median age 10 years (interquartile range, 7, 14 years) with nonglomerular CKD were followed for a median of 4.4 years. The mean baseline GFR in the cohort was 52 ml/min per 1.73 m(2) (95% confidence interval [95% CI], 50 to 54) and declined 1.3 ml/min per 1.73 m(2) per year on average (95%CI, 1.6 to 1.1). A 2-fold higher baseline urine protein-to-creatinine ratio was associated with an accelerated GFR decline of 0.3 ml/min per 1.73 m(2) per year (95% CI, 0.4 to 0.1). A 1-unit higher baseline systolic BP z-score was associated with an additional GFR decline of 0.4 ml/min per 1.73 m(2) per year (95% CI, 0.7 to 0.1). Among normotensive children, larger GFR declines were associated with larger baseline urine protein-to-creatinine ratios; eGFR declines of 0.8 and 1.8 ml/min per 1.73 m(2) per year were associated with urine protein-to-creatinine ratio <0.5 and ≥0.5 mg/mg, respectively. Among children with elevated BP, average GFR declines were evident but were not larger in children with higher levels of proteinuria.

CONCLUSIONS

Baseline proteinuria and systolic BP levels are independently associated with CKD progression in children with nonglomerular CKD.

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.

The effect of abnormal birth history on ambulatory blood pressure and disease progression in children with chronic kidney disease

OBJECTIVE

To examine the associations between abnormal birth history (birth weight <2500 g, gestational age <36 weeks, or small for gestational age), blood pressure (BP), and renal function among 332 participants (97 with abnormal and 235 with normal birth history) in the Chronic Kidney Disease in Children Study, a cohort of children with chronic kidney disease (CKD).

STUDY DESIGN

Casual and 24-hour ambulatory BP were obtained. Glomerular filtration rate (GFR) was determined by iohexol disappearance. Confounders (birth and maternal characteristics, socioeconomic status) were used to generate predicted probabilities of abnormal birth history for propensity score matching. Weighted linear and logistic regression models with adjustment for quintiles of propensity scores and CKD diagnosis were used to assess the impact of birth history on BP and GFR.

RESULTS

Age at enrollment, percent with glomerular disease, and baseline GFR were similar between the groups. Those with abnormal birth history were more likely to be female, of Black race or Hispanic ethnicity, to have low household income, or part of a multiple birth. Unadjusted BP measurements, baseline GFR, and change in GFR did not differ significantly between the groups; no differences were seen after adjusting for confounders by propensity score matching.

CONCLUSIONS

Abnormal birth history does not appear to have exerted a significant influence on BP or GFR in this cohort of children with CKD. The absence of an observed association is likely secondary to the dominant effects of underlying CKD and its treatment.

Rational use of antihypertensive medications in children

Hypertension has traditionally been regarded as an uncommon diagnosis in childhood and adolescence; however, there is compelling evidence to suggest that its prevalence is on the rise, particularly in those with obesity. As a result, pediatricians increasingly are asked to evaluate and manage patients with elevated blood pressure. An increased emphasis on conducting drug trials in children over the last 15 years has yielded important advances with respect to evidence-based data regarding the efficacy and safety of antihypertensive medications in children and adolescents. Unfortunately, data to definitively guide selection of initial agents is lacking. This article will present guidelines for the appropriate use of antihypertensive medications in the pediatric population, including the rational approach to selecting an appropriate medication with respect to pathophysiology, putative benefit, and likelihood for side effects.

Canadian Society of Nephrology commentary on the 2012 KDIGO clinical practice guideline for the management of blood pressure in CKD

The KDIGO (Kidney Disease: Improving Global Outcomes) 2012 clinical practice guideline for the management of blood pressure (BP) in chronic kidney disease (CKD) provides the structural and evidence base for the Canadian Society of Nephrology (CSN) commentary on this guideline's relevancy and application to the Canadian health care system. While in general agreement, we provide commentary on 13 of the 21 KDIGO guideline statements. Specifically, we agreed that nonpharmacological interventions should play a significant role in the management of hypertension in patients with CKD. We also agreed that the approach to the management of hypertension in elderly patients with CKD should be individualized and take into account comorbid conditions to avoid adverse outcomes from excessive BP lowering. In contrast to KDIGO, the CSN Work Group believes there is insufficient evidence to target a lower BP for nondiabetic CKD patients based on the presence and severity of albuminuria. The CSN Work Group concurs with the Canadian Hypertension Education Program (CHEP) recommendation of a target BP for all non-dialysis-dependent CKD patients without diabetes of ≤140 mm Hg systolic and ≤90 mm Hg diastolic. Similarly, it is our position that in diabetic patients with CKD and normal urinary albumin excretion, raising the threshold for treatment from <130 mm Hg systolic BP to <140 mm Hg systolic BP could increase stroke risk and the risk of worsening kidney disease. The CSN Work Group concurs with the CHEP and the Canadian Diabetic Association recommendation for diabetic patients with CKD with or without albuminuria to continue to be treated to a BP target similar to that of the overall diabetes population, aiming for BP levels < 130/80 mm Hg. Consistent with this, the CSN Work Group endorses a BP target of <130/80 mm Hg for diabetic patients with a kidney transplant. Finally, in the absence of evidence for a lower BP target, the CSN Work Group concurs with the CHEP recommendation to target BP<140/90 mm Hg for nondiabetic patients with a kidney transplant.

Treatment Strategies to Prevent Renal Damage in Hypertensive Children

Hypertension secondary to chronic kidney disease prevails in earlier childhood and obesity-related primary hypertension in adolescence. Both are associated with a high risk of renal and cardiovascular morbidity. In children with chronic kidney disease, uncontrolled hypertension may accelerate progression to end-stage renal disease before adulthood is reached and increase a child’s risk of cardiac death a thousand-fold. Obesity-related hypertension is a slow and silent killer, and though early markers of renal damage are recognized during childhood, end-stage renal disease is a risk in later life. Renal damage will be a formidable multiplier of cardiovascular risk for adults in whom obesity and hypertension tracks from childhood. Management options to prevent renal damage will vary for these different target groups. This review provides a summary of the available renoprotective strategies in order to aid physicians involved in the care of this challenging group of children.

Pediatric patients with renal disease and cardiovascular complications: A literature review

The cardiovascular burden of end stage renal disease (ESRD) in children has recently received more attention, and some authors have recommended that the origins of the increase in cardiovascular morbidity and mortality be found in childhood. In this comprehensive review of the literature, we aim to review the main and most recent studies evaluating cardiovascular risk factors in pediatric kidney disease patients. The literature suggests that ESRD, even in the pediatric population, is associated with a high rate of cardiovascular morbidity and mortality, and needs serious attention. Unfortunately, there is extreme scarcity of data on the efficacy of preventive strategies on cardiovascular morbidity and mortality in pediatric patients with renal disease. Therefore, authors of the current article recommend future studies to be directed to find beneficial and/or potential harmful effects of different interventions conventionally used in this population, including lifestyle modifications and pharmaceutical therapy on cardiovascular indices. Moreover, the effects of these drugs on the renal function of children with minimal kidney disease should be evaluated.

BP control and left ventricular hypertrophy regression in children with CKD

In adult patients with CKD, hypertension is linked to the development of left ventricular hypertrophy, but whether this association exists in children with CKD has not been determined conclusively. To assess the relationship between BP and left ventricular hypertrophy, we prospectively analyzed data from the Chronic Kidney Disease in Children cohort. In total, 478 subjects were enrolled, and 435, 321, and 142 subjects remained enrolled at years 1, 3, and 5, respectively. Echocardiograms were obtained 1 year after study entry and then every 2 years; BP was measured annually. A linear mixed model was used to assess the effect of BP on left ventricular mass index, which was measured at three different visits, and a mixed logistic model was used to assess left ventricular hypertrophy. These models were part of a joint longitudinal and survival model to adjust for informative dropout. Predictors of left ventricular mass index included systolic BP, anemia, and use of antihypertensive medications other than angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Predictors of left ventricular hypertrophy included systolic BP, female sex, anemia, and use of other antihypertensive medications. Over 4 years, the adjusted prevalence of left ventricular hypertrophy decreased from 15.3% to 12.6% in a systolic BP model and from 15.1% to 12.6% in a diastolic BP model. These results indicate that a decline in BP may predict a decline in left ventricular hypertrophy in children with CKD and suggest additional factors that warrant additional investigation as predictors of left ventricular hypertrophy in these patients.

Nephrotic-range proteinuria is strongly associated with poor blood pressure control in pediatric chronic kidney disease

Despite the importance of blood pressure (BP) control in chronic kidney disease (CKD), few longitudinal studies on its trends exist for pediatric patients with CKD. Here we longitudinally analyzed casual data in 578 children with CKD and annual BP measurements standardized for age, gender and height. At baseline, 124 children were normotensive, 211 had elevated BP and 243 had controlled hypertension. Linear mixed effects models accounting for informative dropout determined factors associated with BP changes over time and relative sub-hazards (RSH) identified factors associated with the achievement of controlled BP in children with baseline elevated BP. Younger age, black children, higher body mass index, and higher proteinuria at baseline were associated with higher standardized BP levels. Overall average BP decreased during follow-up, but nephrotic range proteinuria, and increased proteinuria and body mass index were risk factors for increasing BP over time. Only 46% of hypertensive patients achieved controlled BP during follow-up; least likely were those with nephrotic range proteinuria (RSH 0.19), black children (RSH 0.42) and children with baseline GFR under 40 ml/min/1.73m² (RSH 0.58). Thus, of many coexisting factors, nephrotic range proteinuria was most strongly associated with poor BP control and worsening BP over time. Future research should focus on strategies to reduce proteinuria, as this may improve BP control and slow the progression of CKD.

Acute changes in blood pressure in patients with neuroblastoma treated with ¹³¹I-metaiodobenzylguanidine (MIBG)

BACKGROUND

Iodine-131-metaiodobenzylguanidine ((131)I-MIBG) provides targeted radiotherapy for children with neuroblastoma. The aim of our study was to evaluate systematically the acute effects of (131)I-MIBG on blood pressure in patients with neuroblastoma and to identify possible predictors of hypertension.

PROCEDURE

We conducted a retrospective chart review of neuroblastoma patients who were treated with (131)I-MIBG between January 1, 1999 and June 1, 2012 at the University of California, San Francisco. Clinical data for 172 patients with neuroblastoma, receiving 218 administrations of (131)I-MIBG, were collected. The primary endpoint was development of systolic blood pressure above the 95th percentile for age. Logistic regression with generalized estimating equations to account for multiple administrations in some subjects was used to identify bivariate and multivariate predictors of hypertension.

RESULTS

Of the 218 administrations of (131)I-MIBG, 112 (51.3%) were associated with at least one episode of systolic hypertension during or after the (131)I-MIBG infusion. The majority of these acute elevations in blood pressure resolved within 48 hours of the infusion. Only six administrations in five patients required nifedipine administration to lower blood pressure. Younger age (P = 0.012), lower eGFR (P = 0.047), and elevated blood pressure measurements immediately before infusion began (P = 0.010) were all independently associated with risk of treatment-associated hypertension.

CONCLUSIONS

Acute elevations in blood pressure are common after therapeutic doses of (131) I-MIBG. Elevations in blood pressure typically occur only within the first 48 hours after (131)I-MIBG administration. Blood pressure monitoring during this period of risk is recommended.