Blood pressure abnormalities in children with chronic kidney disease

Reduced Blood Pressure Dipping Is A Risk Factor for the Progression of Chronic Kidney Disease in Children

Background: Elevated blood pressure and proteinuria are well-established risk factors for chronic kidney disease (CKD) progression in children. This study aimed to analyze risk factors for CKD progress, emphasizing detailed ambulatory blood pressure (ABPM) data. Methods: In 55 children with CKD II−V, observed for ≥1 year or until initiation of kidney replacement therapy, we analyzed ABPM, clinical, and biochemical parameters. Results: At the beginning, the glomerular filtration rate (eGFR) was 66 (interquartile range—IQR: 42.8−75.3) mL/min/1.73 m2, and the observation period was 27 (16−36) months. The mean eGFR decline was 2.9 ± 5.7 mL/min/1.73 m2/year. eGFR decline correlated (p < 0.05) with age (r = 0.30), initial proteinuria (r = 0.31), nighttime systolic and mean blood pressure (r = 0.27, r = 0.29), and systolic and diastolic blood pressure dipping (r = −0.37, r = −0.29). There was no relation between mean arterial pressure during 24 h (MAP 24 h Z-score) and eGFR decline and no difference in eGFR decline between those with MAP 24 h < and ≥50 th percentile. In multivariate analysis, systolic blood pressure dipping (beta = −0.43), presence of proteinuria (beta = −0.35), and age (beta = 0.25) were predictors of eGFR decline. Conclusions: Systolic blood pressure dipping may be a valuable indicator of CKD progression in children.

Circadian disruption and human health

Circadian disruption is pervasive and can occur at multiple organizational levels, contributing to poor health outcomes at individual and population levels. Evidence points to a bidirectional relationship, in that circadian disruption increases disease severity and many diseases can disrupt circadian rhythms. Importantly, circadian disruption can increase the risk for the expression and development of neurologic, psychiatric, cardiometabolic, and immune disorders. Thus, harnessing the rich findings from preclinical and translational research in circadian biology to enhance health via circadian-based approaches represents a unique opportunity for personalized/precision medicine and overall societal well-being. In this Review, we discuss the implications of circadian disruption for human health using a bench-to-bedside approach. Evidence from preclinical and translational science is applied to a clinical and population-based approach. Given the broad implications of circadian regulation for human health, this Review focuses its discussion on selected examples in neurologic, psychiatric, metabolic, cardiovascular, allergic, and immunologic disorders that highlight the interrelatedness between circadian disruption and human disease and the potential of circadian-based interventions, such as bright light therapy and exogenous melatonin, as well as chronotherapy to improve and/or modify disease outcomes.

Ambulatory Blood Pressure and Endothelial Dysfunction in Hematopoietic Cell Transplantation Recipients

Hematopoietic cell transplantation (HCT) is a common treatment for many disorders. Albuminuria post-HCT, which may represent endothelial injury or inflammation from graft- versus-host disease, increases the risk of chronic kidney disease and nonrelapse mortality at 1 year. HCT recipients also have abnormal blood pressure (BP) and increased rates of cardiovascular complications. We sought to determine the relationships among albuminuria, endothelial dysfunction, and BP in HCT recipients. Patients age  ≥12 years who underwent their first allogeneic HCT between 2012 and 2015 and survived through day 80 post-HCT were eligible. Peripheral endothelial function was assessed using the EndoPAT2000 device at day 80 along with 24-hour ambulatory BP monitoring (ABPM). Clinical and laboratory data were collected along with a urine sample for calculation of the albumin-to-creatinine ratio. Both logistic and linear regression analyses were used to identify associations between EndoPAT score and clinical variables. Sixty patients (median age, 48 years; range, 14 to 69 years) completed the study. The median EndoPAT score was 2.05 (range, 1.02 to 4.45), and 17 patients (28%) had abnormal endothelial function. Forty-two patients (72%) had ambulatory hypertension (HTN), and 38 (63%) had blunted nocturnal dipping. HTN on ABPM (P = .045) and blunted nocturnal dipping (P = .04) were associated with a lower EndoPAT score. Albuminuria was not associated with EndoPAT score. There was a lack of agreement between our clinical definition of HTN (office BP and/or use of medications) and ABPM results (P = .04). We did not find an association between lower EndoPAT scores and albuminuria, but did find an association between an abnormal nocturnal dip and HTN diagnosed by ABPM. This suggests that albuminuria may reflect local endothelial injury and inflammation rather than a systemic process. Office BP readings do not accurately reflect true BP, suggesting that 24-hour ABPM studies are needed to diagnose and treat HTN appropriately.

Evaluating risk factors for chronic kidney disease in pediatric patients with sickle cell anemia

BACKGROUND

Patients with sickle cell anemia (SCA) have an increased prevalence of nephropathy and mortality from chronic kidney disease (CKD).

METHODS

We evaluated the association of hyperuricemia and nocturnal hypertension with lower estimated glomerular filtration rate (eGFR) using cystatin-C in patients aged 10-21 years with the HbSS or HbSB0 form of the disease during a non-acute clinic visit. eGFR and uric acid measurements were obtained in 83 and 81 participants, respectively, and 24-h ambulatory blood pressure monitoring (ABPM) was performed in 44 participants. Annual testing included vital signs, complete blood count, comprehensive metabolic panel, medications, urine microalbumin/creatinine, and lactate dehydrogenase measurements. Hyperuricemia was defined as a uric acid level of ≥5.5 mg/dL. Nocturnal hypertension was defined as >25% of nocturnal readings at >95th percentile according to norms established by the American Heart Association Statement on ABPM in children and adolescents.

RESULTS

The mean eGFR was statistically significantly lower in patients with hyperuricemia than in those with normal uric acid levels (143 vs. 161 mL/min/1.73 m², respectively). Of the 44 participants for whom ABPM data were available, 14 (32%) had systolic nocturnal hypertension and 12 (27%) had diastolic nocturnal hypertension. The mean eGFR was statistically significantly lower in participants with nocturnal systolic and diastolic hypertension than in those with normal nocturnal blood pressure. In a regression model, nocturnal hypertension and hyperuricemia were associated with a lower eGFR.

CONCLUSIONS

Two risk factors for CKD, i.e., nocturnal hypertension and hyperuricemia, were associated with lower eGFR in older children and adolescent patients with SCA. Long-term studies on their association with progression to CKD in this population are warranted.

KEY POINT

Nocturnal hypertension and hyperuricemia are established risk factors for nephropathy in other diseases and may play a role in SCA nephropathy.

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.

Evidence-based guidelines for the management of hypertension in children with chronic kidney disease

Hypertension is common in children with chronic kidney disease and early evidence suggests that it is a modifiable risk factor for renal and cardiovascular outcomes. Recommendations for blood pressure management in children with chronic kidney disease can be found in various clinical practice guidelines including the 4th Task Force Report, the European Society of Hypertension pediatric recommendations, and the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI) and Kidney Disease: Improving Global Outcomes (KDIGO) guidelines for the management of blood pressure in chronic kidney disease. Unfortunately, as pediatric trial evidence is limited, there are discrepancies in the recommendations that may lead to inconsistent clinical care and practice variation. This article reviews the strength of evidence behind each of the clinical practice guideline recommendations regarding blood pressure assessment, treatment targets, and first-line antihypertensive medications. The benefits and cautions of use of clinical practice guidelines are described with emphasis on the importance of reading beyond the summary statements.

Nocturnal blood pressure non-dipping is prevalent in severely obese, prepubertal and early pubertal children

AIM

To investigate the prevalence of nocturnal blood pressure dipping among obese prepubertal and early pubertal children and to analyse the relationship between dipping and measures of insulin-glucose metabolism or sleep-disordered breathing.

METHODS

We studied 76 obese children (41% girls) under clinical care, with an average age of 10.4 ± 1.7 and a body mass index Z-score (BMI Z-score) of 6.2 ± 1.6. We performed a 24-h ambulatory blood pressure measurement. Non-dipping was defined as a nocturnal blood pressure reduction of <10%. We calculated measures of insulin-glucose metabolism from the performed frequently sampled intravenous glucose-tolerance test and from fasting blood samples. Overnight sleep polygraph recordings were performed to assess sleep-disordered breathing.

RESULTS

Forty-two percent of the children were systolic non-dippers, and 17% were diastolic non-dippers. There were no associations between systolic or diastolic dipping and measures of insulin-glucose metabolism after adjustments for BMI Z-score, gender and pubertal status. There were no associations between dipping and measures of sleep-disordered breathing.

CONCLUSION

Nocturnal non-dipping was two times higher among severely obese, prepubertal and early pubertal children, compared to previous reports among children in general. There were no associations between nocturnal dipping and insulin-glucose metabolism or measures of sleep-disordered breathing in this group.

Hypertension and future cardiovascular health in pediatric end-stage renal disease patients

BACKGROUND

There are now numerous studies that have documented an increased risk of cardiovascular morbidity and mortality in young adults who had childhood-onset end-stage renal disease (ESRD). Since the number of such patients surviving to adulthood is increasing, strategies to reduce this risk are urgently needed.

METHODS

The various risk factors contributing to adult cardiovascular disease in this population will be reviewed, with an emphasis on hypertension and its control. Data demonstrating the prevalence of hypertension in childhood chronic kidney disease as well as the results of improved blood pressure control in ESRD will also be presented.

CONCLUSIONS

Hypertension is exceedingly common in pediatric ESRD patients and frequently poorly controlled. Efforts to improve blood pressure control in this patient population could potentially reduce future cardiovascular morbidity and mortality.

Hypertension and CKD

Hypertension is found in more than 50% of pediatric patients with CKD. However, its prevalence varies according to the cause of CKD. It is relatively infrequent in children with structural disorders. Acquired renal disorders are associated with an increased prevalence of hypertension, similar to that of adults. Recent studies using ambulatory blood pressure monitoring indicate that children with CKD also have a high prevalence of masked hypertension. Similar to adults, long-standing and uncontrolled hypertension in children is associated with the progression of CKD and development of end-organ damage including early cardiomyopathy and premature atherosclerosis. Aggressive treatment of hypertension should be an essential part of pediatric CKD care, not just to prevent the development of symptomatic cardiovascular disease but also to delay progression of CKD. Recent findings from the European Effect of Strict Blood Pressure Control and ACE Inhibition on Progression of Chronic Renal Failure in Pediatric Patients (ESCAPE) trial have shown that the aggressive treatment of blood pressure, to below the 50th percentile, has even greater benefit in children with CKD, unlike results seen in adult studies.

Role of twenty-four-hour ambulatory blood pressure monitoring in children on dialysis

BACKGROUND AND OBJECTIVES

Pre- or postdialysis BP recordings are imprecise, can be biased, and have poor test-retest reliability in children on dialysis. We aimed to examine the possible differences between pre- and postdialysis BP levels and 24-hour ambulatory BP monitoring (ABPM) in diagnosis of hypertension (HTN).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Twenty-four children on dialysis had 24-hour ABPM in the interdialytic period, and values were compared with average pre- and postdialysis systolic BP (SBP) and diastolic BP (DBP) recordings that week. Each patient had an echocardiogram to determine presence of left ventricular hypertrophy (LVH).

RESULTS

By ABPM, 8% of patients had white coat HTN and 12% had masked HTN. There was no significant difference in diagnosis of systolic HTN based on ABPM daytime SBP mean or load and postdialysis SBP. However, only 15% of patients had diastolic HTN based on postdialysis measures, whereas 46% of patients had significantly elevated daytime DBP loads and 71% had high nighttime DBP loads on ABPM. Forty-eight percent of patients were SBP nondippers. Children with LVH had higher daytime and nighttime SBP loads, significantly higher daytime and nighttime DBP loads, and lesser degree of nocturnal dipping of SBP compared with those who did not.

CONCLUSION

ABPM is more informative than pre- and postdialysis BPs and improves the predictability of BP as a risk factor for target organ damage. Diagnosis and treatment monitoring of HTN among pediatric dialysis patients is enhanced with addition of ABPM.

Longitudinal formulas to estimate GFR in children with CKD

BACKGROUND AND OBJECTIVES

Whereas current GFR estimating equations approximate direct GFR measurement at a single time point, formulas that capitalize on changes in easily measured biologic parameters could improve the accuracy and precision of GFR estimation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In the Chronic Kidney Disease in Children Cohort (aged 1 to 16 yr), we measured GFR by plasma disappearance of iohexol (iGFR) and biomarkers in the first two annual visits. Models took the form GFR(2) = a[GFR(1)/40](b)[X(2)/X(1)](c), where GFR(2) and GFR(1) represented the current and previous years' iGFR, 40 ml/min per 1.73 m(2) was the cohort mean, and X(2)/X(1) was the change in predictors over time. Using data from 360 participants with a median age of 12.1 yr, we evaluated the predictive performance of a past GFR measurement and 20 other variables using a two-thirds random sample of the data. A one-third sample was reserved for validation.

RESULTS

Previous iGFR measurements were strongly predictive of subsequent iGFR and adding change in height/serum creatinine significantly improved the explanatory power to 78%. In the validation set, the correlation between estimated and measured GFR was 0.88, and 48 and 88% of estimated GFRs were within 10 and 30% of observed iGFRs. When the past GFR measurement was not used, addition of change in markers to a cross-sectional model did not improve prediction.

CONCLUSIONS

Longitudinal formulas to estimate iGFR capitalize on the high predictive power of previous iGFR measurements and in this study yielded a parsimonious prediction model with the potential for assessing progression in the clinical setting.