Patterns of recombinant growth hormone therapy use and growth responses among children with chronic kidney disease

BACKGROUND

Recombinant growth hormone (rGH) is an efficacious therapy for growth failure in children with chronic kidney disease (CKD). We described rGH use and estimated its relationship with growth and kidney function in the Chronic Kidney Disease in Children (CKiD) cohort.

METHODS

Participants included those with growth failure, prevalent rGH users, and rGH initiators who did not meet growth failure criteria. Among those with growth failure, height z scores and GFR were compared between rGH initiators and non-initiators across 42 months. Inverse probability weights accounted for differences in baseline variables in weighted linear regressions.

RESULTS

Among 148 children with growth failure and no previous rGH therapy, 42 (28%) initiated rGH therapy. Of the initiators, average age was 8.9 years, height z score was 2.50 standard deviations (SDs) (0.6^th percentile), and GFR was 44 ml/min/1.73m². They were compared to 106 children with growth failure who never initiated therapy (8.8 years, -2.33 SDs, and 51 ml/min/1.73m²). At 30 and 42 months after rGH, height increased +0.26 (95%CI: -0.11, +0.62) and +0.35 (95%CI: -0.17, +0.87) SDs, respectively, relative to those who did not initiate rGH. rGH was not associated with GFR.

CONCLUSIONS

Participants with growth failure receiving rGH experienced significant growth, although this was attenuated relative to RCTs, and were more likely to have higher household income and lower GFR. A substantial number of participants, predominantly boys, without diagnosed growth failure received rGH and had the highest achieved height relative to mid-parental height. Since rGH was not associated with accelerated GFR decline, increasing rGH use in this population is warranted.

Diastolic Function and Ambulatory Hypertension in Children With Chronic Kidney Disease

[Figure: see text].

Variability in CKD Biomarker Studies: Soluble Urokinase Plasminogen Activator Receptor (suPAR) and Kidney Disease Progression in the Chronic Kidney Disease in Children (CKiD) Study

Rationale & Objective

Biomarker studies are important for generating mechanistic insight and providing clinically useful predictors of chronic kidney disease (CKD) progression. However, variability across studies can often muddy the evidence waters. Here we evaluated real-world variability in biomarker studies using two published studies, independently conducted, of the novel plasma marker soluble urokinase-type plasminogen activator receptor (suPAR) for predicting CKD progression in children with CKD.

Study Design

A comparison of 2 prospective cohort studies.

Setting & Participants

541 children from the Chronic Kidney Disease in Children (CKiD) study, median age 12 years, median glomerular filtration rate (GFR) of 54 mL/min/1.73m².

Outcome

The first occurrence of either a 50% decline in GFR from baseline or incident end-stage kidney disease.

Analytical Approach

The suPAR plasma marker was measured using the Quantikine ELISA immunoassay in the first study and Meso Scale Discovery (MSD) platform in the second. The analytical approaches varied. We used suPAR data from the 2 assays and mimicked each analytical approach in an overlapping subset.

Results

We found that switching assays had the greatest impact on inferences, resulting in a 38% to 66% change in the magnitude of the effect estimates. Covariate and modeling choices resulted in an additional 8% to 40% variability in the effect estimate. The cumulative variability led to different inferences despite using a similar sample of CKiD participants and addressing the same question.

Limitations

The estimated variability does not represent optimal repeatability but instead illustrates real-world variability that may be present in the CKD biomarker literature.

Conclusions

Our results highlight the importance of validation, avoiding conclusions based on P value thresholds, and providing comparable metrics. Further transparency of data and equal weighting of negative and positive findings in explorations of novel biomarkers will allow investigators to more quickly weed out less promising biomarkers.

Management of Blood Pressure in Patients With Chronic Kidney Disease Not Receiving Dialysis: Synopsis of the 2021 KDIGO Clinical Practice Guideline

DESCRIPTION

The Kidney Disease: Improving Global Outcomes (KDIGO) 2021 clinical practice guideline for the management of blood pressure (BP) in patients with chronic kidney disease (CKD) not receiving dialysis is an update of the KDIGO 2012 guideline on the same topic and reflects new evidence on the risks and benefits of BP-lowering therapy among patients with CKD. It is intended to support shared decision making by health care professionals working with patients with CKD worldwide. This article is a synopsis of the full guideline.

METHODS

The KDIGO leadership commissioned 2 co-chairs to convene an international Work Group of researchers and clinicians. After a Controversies Conference in September 2017, the Work Group defined the scope of the evidence review, which was undertaken by an evidence review team between October 2017 and April 2020. Evidence reviews were done according to the Cochrane Handbook. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach was used to guide the development of the recommendations and rate the strength and quality of the evidence. Practice points were included to provide guidance when evidence was insufficient to make a graded recommendation. The guideline was revised after public consultation between January and March 2020.

RECOMMENDATIONS

The updated guideline comprises 11 recommendations and 20 practice points. This synopsis summarizes key recommendations pertinent to the diagnosis and management of high BP in adults with CKD, excluding those receiving kidney replacement therapy. In particular, the synopsis focuses on recommendations for standardized BP measurement and a target systolic BP of less than 120 mm Hg, because these recommendations differ from some other guidelines.

Commentary on the KDIGO 2021 Clinical Practice Guideline for the Management of Blood Pressure in CKD

PURPOSE OF REVIEW

To summarize and explain the new guideline on blood pressure (BP) management in chronic kidney disease (CKD) published by Kidney Disease: Improving Global Outcomes (KDIGO), an independent global nonprofit organization which develops and implements evidence-based clinical practice guidelines in kidney disease. KDIGO issued its first clinical practice guideline for the Management of Blood Pressure (BP) in Chronic Kidney Disease (CKD) for patients not receiving dialysis in 2012 and now updated the guideline in 2021.

RECENT FINDINGS

Recommendations in this update were developed based on systematic literature reviews and appraisal of the quality of the evidence and strength of recommendation following the "Grading of Recommendations Assessment, Development and Evaluation" (GRADE) approach. The updated guideline includes five chapters covering BP measurement techniques, lifestyle interventions for lowering BP, and management of BP in three target populations, namely adults (with and without diabetes), kidney transplant recipients, and children. A dedicated chapter on BP measurement emphasizing standardized preparation and measurement protocols for office BP measurement is a new addition, following protocols used in large randomized trials of BP targets with pivotal clinical outcomes. Based on the available evidence, and in particular in the CKD subgroup of the SPRINT trial, the 2021 guideline suggests a systolic BP target of <120 mm Hg, based on standardized measurements, for most individuals with CKD not receiving dialysis, with the exception of kidney transplant recipients and children. This recommendation is strictly contingent on the measurement of BP using standardized office readings and not routine office readings.

L-type calcium channel blocker use and proteinuria among children with chronic kidney diseases

BACKGROUND

Hypertension is common among children with chronic kidney disease (CKD), and dihydropyridine calcium channel blockers (dhCCBs) are frequently used as treatment. The impact of dhCCBs on proteinuria in children with CKD is unclear.

METHODS

Data from 722 participants in the Chronic Kidney Disease in Children (CKiD) longitudinal cohort with a median age of 12 years were used to assess the association between dhCCBs and log transformed urine protein/creatinine levels as well as blood pressure control measured at annual visits. Angiotensin-converting enzyme inhibitor (ACEi) and angiotensin receptor blocker (ARB) use was evaluated as an effect measure modifier.

RESULTS

Individuals using dhCCBs had 18.8% higher urine protein/creatinine levels compared to those with no history of dhCCB or ACEi and ARB use. Among individuals using ACEi and ARB therapy concomitantly, dhCCB use was not associated with an increase in proteinuria. Those using dhCCBs had higher systolic and diastolic blood pressures.

CONCLUSIONS

Use of dhCCBs in children with CKD and hypertension is associated with higher levels of proteinuria and was not found to be associated with improved blood pressure control.

Metabolite Biomarkers of CKD Progression in Children

BACKGROUND AND OBJECTIVES

Metabolomics facilitates the discovery of biomarkers and potential therapeutic targets for CKD progression.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We evaluated an untargeted metabolomics quantification of stored plasma samples from 645 Chronic Kidney Disease in Children (CKiD) participants. Metabolites were standardized and logarithmically transformed. Cox proportional hazards regression examined the association between 825 nondrug metabolites and progression to the composite outcome of KRT or 50% reduction of eGFR, adjusting for age, sex, race, body mass index, hypertension, glomerular versus nonglomerular diagnosis, proteinuria, and baseline eGFR. Stratified analyses were performed within subgroups of glomerular/nonglomerular diagnosis and baseline eGFR.

RESULTS

Baseline characteristics were 391 (61%) male; median age 12 years; median eGFR 54 ml/min per 1.73 m²; 448 (69%) nonglomerular diagnosis. Over a median follow-up of 4.8 years, 209 (32%) participants developed the composite outcome. Unique association signals were identified in subgroups of baseline eGFR. Among participants with baseline eGFR ≥60 ml/min per 1.73 m², two-fold higher levels of seven metabolites were significantly associated with higher hazards of KRT/halving of eGFR events: three involved in purine and pyrimidine metabolism (N6-carbamoylthreonyladenosine, hazard ratio, 16; 95% confidence interval, 4 to 60; 5,6-dihydrouridine, hazard ratio, 17; 95% confidence interval, 5 to 55; pseudouridine, hazard ratio, 39; 95% confidence interval, 8 to 200); two amino acids, C-glycosyltryptophan, hazard ratio, 24; 95% confidence interval 6 to 95 and lanthionine, hazard ratio, 3; 95% confidence interval, 2 to 5; the tricarboxylic acid cycle intermediate 2-methylcitrate/homocitrate, hazard ratio, 4; 95% confidence interval, 2 to 7; and gulonate, hazard ratio, 10; 95% confidence interval, 3 to 29. Among those with baseline eGFR <60 ml/min per 1.73 m², a higher level of tetrahydrocortisol sulfate was associated with lower risk of progression (hazard ratio, 0.8; 95% confidence interval, 0.7 to 0.9).

CONCLUSIONS

Untargeted plasma metabolomic profiling facilitated discovery of novel metabolite associations with CKD progression in children that were independent of established clinical predictors and highlight the role of select biologic pathways.

The association of alcohol, cigarette, e-cigarette, and marijuana use with disease severity in adolescents and young adults with pediatric chronic kidney disease

BACKGROUND

We investigated the putative associations of alcohol, cigarette, e-cigarette, and marijuana use with kidney function and proteinuria among adolescents and young adults (AYA) with pediatric-onset chronic kidney disease (CKD) enrolled in the Chronic Kidney Disease in Children (CKiD) study.

METHODS

Participants responded to questions about past year and 30-day substance use. Associations between each substance and kidney function, proteinuria, nephrotic range proteinuria, and high blood pressure were separately estimated using repeated measures regression models, adjusting for sociodemographic characteristics. Models controlled for covariates at the present visit (contemporaneous) and additionally controlled for disease severity at the year prior to reporting substance use (lagged).

RESULTS

A total of 441 participants ≥16 years contributed 1,245 person-visits with 39% reporting alcohol and 16%, 17%, and 15% reporting cigarette, e-cigarette, and marijuana use, respectively, over the previous year. In adjusted lagged models, past year and 30-day cigarette use were significantly associated with higher levels of proteinuria (+18.6%, 95%CI: +2.8%, +36.9%; and +20.0%, 95%CI: +0.7%, +43.1%, respectively). Inferences were similar when controlling for secondhand smoke exposure.

CONCLUSIONS

In a cohort of AYA with pediatric kidney diseases, substance use was non-trivial, and cigarette use was associated with higher proteinuria, although the prevalence of use was low. Occasional alcohol, e-cigarette, and marijuana use were not associated with proteinuria, disease progression, or elevated blood pressure. Pediatric nephrologists as specialty care providers are well-positioned to discuss substance use and should encourage tobacco prevention/treatment efforts among AYA at high risk for use in order to preserve kidney function and promote well-being.

Longitudinal outcomes of body mass index in overweight and obese children with chronic kidney disease

BACKGROUND

Longitudinal changes in body mass index (BMI) among overweight and obese children with chronic kidney disease (CKD) are not well characterized. We studied longitudinal trajectories and correlates of these trajectories, as results may identify opportunities to optimize health outcomes.

METHODS

Longitudinal changes in age-sex-specific BMI z-scores over 1851 person-years of follow-up were assessed in 524 participants of the Chronic Kidney Disease in Children Study. A total of 353 participants were categorized as normal (BMI > 5th to < 85th percentile), 56 overweight (BMI ≥ 85th to 95th percentile) and 115 obese (BMI ≥ 95th percentile) based on the average of three BMI measurements during the first year of follow-up. Studied covariates included age, sex, race, CKD etiology, corticosteroid usage, household income, and maternal education.

RESULTS

In unadjusted analysis, BMI z-scores decreased over time in elevated BMI groups (overweight: mean = - 0.06 standard deviations (SD) per year, 95% CI: - 0.11, - 0.01; obese: mean = - 0.04 SD per year, 95% CI: - 0.07, - 0.01). Among obese children, only age was associated with change in BMI z-score; children < 6 years had a mean decrease of 0.19 SD during follow-up (95% CI: - 0.30, - 0.09). Socioeconomic factors were not associated with change in BMI.

CONCLUSION

Overweight and obese children with CKD demonstrated a significant annual decline in BMI, though the absolute change was modest. Among obese children, only age < 6 years was associated with significant decline in BMI. Persistence of elevated BMI in older children and adolescents with CKD underscores the need for early prevention and effective intervention.

Patient and caregiver perspectives on blood pressure in children with chronic kidney disease

BACKGROUND

Over 50% of children with chronic kidney disease (CKD) have uncontrolled hypertension, increasing their long-term risk of cardiovascular disease and progression to kidney failure. Children receiving medications or dialysis may also experience acute blood pressure fluctuations accompanied by debilitating symptoms. We aimed to describe the perspectives of children with CKD and their parental caregivers on blood pressure, to inform patient-centered care.

METHODS

Secondary thematic analysis was conducted on qualitative data from the Standardized Outcomes in Nephrology-Children and Adolescents initiative, encompassing 16 focus groups, an international Delphi survey, and two consensus workshops. We analyzed responses from children with CKD (aged 8-21 years) and caregivers (of children aged 0-21 years) pertaining to blood pressure.

RESULTS

Overall, 120 patients and 250 caregivers from 22 countries participated. We identified five themes: invisibility and normalization (reassured by apparent normotension, absence of symptoms, expected links with CKD); confused by ambiguity (hypertension indistinguishable from cardiovascular disease, questioning need for prophylactic intervention, frustrated by inconsistent messages, struggling with technical skills in measurement); enabling monitoring and maintaining health (gauging wellbeing, preventing vascular complications); debilitating and constraining daily living (provoking anxiety and agitation, helpless and powerless, limiting life activities); and burden of medications (overwhelmed by quantity of tablets, distress from unexpected side effects).

CONCLUSIONS

For children with CKD and their caregivers, blood pressure was an important heath indicator, but uncertainty around its implications and treatment hampered management. Providing educational resources to track blood pressure, and minimizing symptoms and treatment burden, may improve outcomes in children with CKD.

Mean Arterial Pressure and Chronic Kidney Disease Progression in the CKiD Cohort

[Figure: see text].

Achieved clinic blood pressure level and chronic kidney disease progression in children: a report from the Chronic Kidney Disease in Children cohort

BACKGROUND

Control of hypertension delays progression of pediatric chronic kidney disease (CKD), yet few data are available regarding what clinic blood pressure (BP) levels may slow progression.

METHODS

Longitudinal BP data from children in the Chronic Kidney Disease in Children cohort study who had hypertension or an auscultatory BP ≥ 90th percentile were studied. BP categories were defined as the maximum systolic or diastolic BP percentile (< 50th, 50th to 75th, 75th to 90th, and ≥ 90th percentile) with time-updated classifications corresponding to annual study visits. The primary outcome was time to kidney replacement therapy or a 30% decline in estimated glomerular filtration rate. Cox proportional hazard models described the effect of each BP category compared to BP ≥ 90th percentile.

RESULTS

Seven hundred fifty-four participants (median age 9.9 years at study entry) met inclusion criteria; 65% were male and 26% had glomerular CKD. Any BP < 90th percentile was associated with a decreased risk of progression for those with glomerular CKD (hazard ratio (HR), 0.63; 95% CI, 0.28-1.39 (< 50th); HR, 0.59; 95% CI, 0.28-1.26 (50th-75th); HR, 0.40; 95% CI, 0.18-0.93 (75th-90th)). Similar results were found for those with non-glomerular CKD: any BP < 90th percentile was associated with decreased risk of progression (HR, 0.78; 90% CI, 0.49-1.25 (< 50th); HR, 0.53; 95% CI, 0.33-0.84 (50th-75th); HR, 0.71; 95% CI, 0.46-1.08 (75th-90th)).

CONCLUSIONS

Achieved clinic BP < 90th percentile was associated with slower CKD progression in children with glomerular or non-glomerular CKD. These data provide guidance for management of children with CKD in the office setting. Graphical abstract.

The Natural History of BK Polyomavirus and the Host Immune Response After Stem Cell Transplantation

BACKGROUND

BK polyomavirus (BKPyV) is associated with symptomatic hemorrhagic cystitis after hematopoietic cell transplantation (HCT). Little is known about the host immune response, effectiveness of antiviral treatment, or impact of asymptomatic replication on long-term kidney function.

METHODS

In children and young adults undergoing allogeneic HCT, we quantified BKPyV viruria and viremia (pre-HCT and at Months 1-4, 8, 12, and 24 post-HCT) and tested associations of peak viremia ≥10 000 or viruria ≥109 copies/mL with estimated kidney function (glomerular filtration rate, eGFR) and overall survival at 2 years posttransplant. We examined the factors associated with viral clearance by Month 4, including BKPyV-specific T cells by enzyme-linked immune absorbent spot at Month 3 and cidofovir use.

RESULTS

We prospectively enrolled 193 participants (median age 10 years) and found that 18% had viremia ≥10 000 copies/mL and 45% had viruria ≥109 copies/mL in the first 3 months post-HCT. Among the 147 participants without cystitis (asymptomatic), 58 (40%) had any viremia. In the entire cohort and asymptomatic subset, having viremia ≥10 000 copies/mL was associated with a lower creatinine/cystatin C eGFR at 2 years post-HCT. Viremia ≥10 000 copies/mL was associated with a higher risk of death (adjusted hazard ratio, 2.2; 95% confidence interval, 1.1-4.2). Clearing viremia was associated with detectable BKPyV-specific T cells and having viremia <10 000 copies/mL, but not cidofovir exposure.

CONCLUSIONS

Screening for BKPyV viremia after HCT identifies asymptomatic patients at risk for kidney disease and reduced survival. These data suggest potential changes to clinical practice, including prospective monitoring for BKPyV viremia to test virus-specific T cells to prevent or treat BKPyV replication.

Alcohol, cigarette, e-cigarette and marijuana use among adolescents and young adults with chronic kidney disease in North America

PURPOSE

This study aimed to describe substance use (SU) among adolescents and young adults (AYA) with chronic kidney disease, compare these findings with the general population, and identify associated risk factors.

METHODS

708 AYA participants contributing 2475 person-visits from the Chronic Kidney Disease in Children Study were used to estimate prevalence rates of past year and 30-day alcohol, cigarette, e-cigarette and marijuana use, and were compared with national surveys. Repeated measures logistic regression estimated the association between SU and participant characteristics.

RESULTS

There was nearly no SU among those 12 to 14 years, but use increased with age, and past year alcohol use was about 80% for those greater than or equal to 22 years. Rates of use among males were constant or increased with age, while rates of use among females were lower after age 22 compared to ages 18 to 22. Associated risk factors included non-Black and non-Hispanic identity, older age, and worse disease severity. Participants were less likely to use substances compared to the general population, especially those 14-18 years.

CONCLUSIONS

SU was less common in AYA with chronic kidney disease than the general population, but differences were attenuated among those greater than or equal to 18 years. Ages 12-14 appear to be the ideal time for prevention efforts. As the landscape of e-cigarette and marijuana policies change, these results underscore the need to understand how similar high-risk populations engage in SU.

Copy Number Variant Analysis and Genome-wide Association Study Identify Loci with Large Effect for Vesicoureteral Reflux

BACKGROUND

Vesicoureteral reflux (VUR) is a common, familial genitourinary disorder, and a major cause of pediatric urinary tract infection (UTI) and kidney failure. The genetic basis of VUR is not well understood.

METHODS

A diagnostic analysis sought rare, pathogenic copy number variant (CNV) disorders among 1737 patients with VUR. A GWAS was performed in 1395 patients and 5366 controls, of European ancestry.

RESULTS

Altogether, 3% of VUR patients harbored an undiagnosed rare CNV disorder, such as the 1q21.1, 16p11.2, 22q11.21, and triple X syndromes ((OR, 3.12; 95% CI, 2.10 to 4.54; P=6.35×10^-8) The GWAS identified three study-wide significant and five suggestive loci with large effects (ORs, 1.41-6.9), containing canonical developmental genes expressed in the developing urinary tract (WDPCP, OTX1, BMP5, VANGL1, and WNT5A). In particular, 3.3% of VUR patients were homozygous for an intronic variant in WDPCP (rs13013890; OR, 3.65; 95% CI, 2.39 to 5.56; P=1.86×10^-9). This locus was associated with multiple genitourinary phenotypes in the UK Biobank and eMERGE studies. Analysis of Wnt5a mutant mice confirmed the role of Wnt5a signaling in bladder and ureteric morphogenesis.

CONCLUSIONS

These data demonstrate the genetic heterogeneity of VUR. Altogether, 6% of patients with VUR harbored a rare CNV or a common variant genotype conferring an OR >3. Identification of these genetic risk factors has multiple implications for clinical care and for analysis of outcomes in VUR.

Age- and sex-dependent clinical equations to estimate glomerular filtration rates in children and young adults with chronic kidney disease

Using data (2655 observations from 928 participants) from the Chronic Kidney Disease in Children Study, we developed and internally validated new glomerular filtration rate estimating equations for clinical use in children and young adults: two forms of K × [heigh(ht) / serum creatinine(sCr)] and two forms of K × [1 / cystatin C(cysC)]. For each marker, one equation used a sex-dependent K; in the other, K is sex-and age-dependent. Glomerular filtration rate (GFR) was measured directly by plasma iohexol disappearance. The equations using ht⁄sCr had sex-specific constants of 41.8 for males and 37.6 for females. In the age- dependent models, K increased monotonically for children 1-18 years old and was constant for young adults 18-25 years. For males, K ranged from 35.7 for one-year-olds to 50.8 for those 18 and older. For females, the values of K ranged from 33.1 to 41.4. Constant K values for cystatin-C equations were 81.9 for males and 74.9 for females. With age-dependency, K varied non-monotonically with the highest values at age 15 for males (K of 87.2) and 12 years for females (K of 79.9). Use of an age-dependent K with ht/sCr models reduced average bias, notably in young children and young adults; age-dependent cystatin-C models produced similar agreement to using a constant K in children under 18 years, but reduced bias in young adults. These age-dependent proposed equations were evaluated alongside estimated GFRs from 11 other published equations for pediatrics and young adults. Only our proposed equations yielded non- significant bias and within 30% accuracy values greater than 85% in both the pediatric and young adult subpopulations.

Kidney Outcomes and Hypertension in Survivors of Wilms Tumor: A Prospective Cohort Study

OBJECTIVE

To assess the prevalence of therapy-related kidney outcomes in survivors of Wilms tumor (WT).

STUDY DESIGN

This prospective cohort study included survivors of WT who were ≥5 years old and ≥1 year from completing therapy, excluding those with preexisting hypertension, prior dialysis, or kidney transplant. Participants completed 24-hour ambulatory blood pressure monitoring (ABPM). Abnormal blood pressure (BP) was defined as ≥90th percentile. Masked hypertension was defined as having normal office BP and abnormal ABPM findings. Urine was analyzed for kidney injury molecule-1, interleukin-18, epidermal growth factor, albumin, and creatinine. The estimated glomerular filtration rate (eGFR) was calculated using the bedside chronic kidney disease in children equation. Recent kidney ultrasound examinations and echocardiograms were reviewed for contralateral kidney size and left ventricular hypertrophy, respectively. Clinical follow-up data were collected for approximately 2 years after study enrollment.

RESULTS

Thirty-two participants (median age, 13.6 years [IQR, 10.5-16.3 years]; 75% stage 3 or higher WT) were evaluated at a median of 8.7 years (IQR, 6.5-10.8 years) after therapy; 29 participants underwent unilateral radical nephrectomy, 2 bilateral partial nephrectomy, and 1 radical and contralateral partial nephrectomy. In this cohort, 72% received kidney radiotherapy and 75% received doxorubicin. Recent median eGFR was 95.6 mL/min/1.73 m² (IQR, 84.6-114.0; 11 [34%] had an eGFR of <90 mL/min/1.73 m²). Abnormal ABPM results were found in 22 of 29 participants (76%), masked hypertension in 10 of 29 (34%), and microalbuminuria in 2 of 32 (6%). Of the 32 participants, 22 (69%) had abnormal epidermal growth factor; few had abnormal kidney injury molecule-1 or interleukin-18. Seven participants with previous unilateral nephrectomy lacked compensatory contralateral kidney hypertrophy. None had left ventricular hypertrophy.

CONCLUSIONS

In survivors of WT, adverse kidney outcomes were common and should be closely monitored.

Executive summary of the KDIGO 2021 Clinical Practice Guideline for the Management of Blood Pressure in Chronic Kidney Disease

The Kidney Disease: Improving Global Outcomes (KDIGO) 2021 Clinical Practice Guideline for the Management of Blood Pressure in Chronic Kidney Disease for patients not receiving dialysis represents an update to the KDIGO 2012 guideline on this topic. Development of this guideline update followed a rigorous process of evidence review and appraisal. Guideline recommendations are based on systematic reviews of relevant studies and appraisal of the quality of the evidence. The strength of recommendations is based on the "Grading of Recommendations Assessment, Development and Evaluation" (GRADE) approach. The scope includes topics covered in the original guideline, such as optimal blood pressure targets, lifestyle interventions, antihypertensive medications, and specific management in kidney transplant recipients and children. Some aspects of general and cardiovascular health, such as lipid and smoking management, are excluded. This guideline also introduces a chapter dedicated to proper blood pressure measurement since all large randomized trials targeting blood pressure with pivotal outcomes used standardized preparation and measurement protocols adhered to by patients and clinicians. Based on previous and new evidence, in particular the Systolic Blood Pressure Intervention Trial (SPRINT) results, we propose a systolic blood pressure target of less than 120 mm Hg using standardized office reading for most people with chronic kidney disease (CKD) not receiving dialysis, the exception being children and kidney transplant recipients. The goal of this guideline is to provide clinicians and patients a useful resource with actionable recommendations supplemented with practice points. The burden of the recommendations on patients and resources, public policy implications, and limitations of the evidence are taken into consideration. Lastly, knowledge gaps and recommendations for future research are provided.

The CKiD study: overview and summary of findings related to kidney disease progression

The Chronic Kidney Disease in Children (CKiD) cohort study is a North American (USA and Canada) multicenter, prospective study of children with chronic kidney disease (CKD). The original aims of the study were (1) to identify novel risk factors for CKD progression; (2) to measure the impact of kidney function decline on growth, cognition, and behavior; and (3) to characterize the evolution of cardiovascular disease risk factors. CKiD has developed into a national and international resource for the investigation of a variety of factors related to CKD in children. This review highlights notable findings in the area of CKD progression and outlines ongoing opportunities to enhance understanding of CKD progression in children. CKiD's contributions to the clinical care of children with CKD include updated and more accurate glomerular filtration rate estimating equations for children and young adults, and resources designed to help estimate the CKD progression timeline. In addition, results from CKiD have strengthened the evidence that treatment of hypertension and proteinuria should continue as a primary strategy for slowing the rate of disease progression in children.

Social Determinants of Cardiovascular Health in African American Children With CKD: An Analysis of the Chronic Kidney Disease in Children (CKiD) Study

RATIONALE & OBJECTIVE

To identify differences in socioeconomic factors (SES) and subclinical cardiovascular disease (CVD) markers by race among Chronic Kidney Disease in Children (CKiD) participants and determine whether differences in CVD markers persist after adjusting for SES.

STUDY DESIGN

Analysis of 3,103 visits with repeated measures from 628 children (497 White participants; 131 African American participants) enrolled in the CKiD study.

SETTING & PARTICIPANTS

Children with mild-moderate CKD with at least 1 cardiovascular (CV) parameter (ambulatory blood pressure, left ventricular mass index [LVMI], or lipid profile) measured.

EXPOSURE

African American race.

OUTCOMES

Ambulatory hypertension, LVMI, triglycerides, high-density lipoprotein cholesterol.

ANALYTICAL APPROACH

Due to increased CV risks of glomerular disease, the analysis was stratified by CKD cause. Inverse probability weighting was used to adjust for SES (health insurance, household income, maternal education, food insecurity, abnormal birth history). Linear and logistic regression were used to evaluate association of race with CV markers.

RESULTS

African American children were disproportionately affected by adverse SES. African Americans with nonglomerular CKD had more instances of ambulatory hypertension and higher LVMI but more favorable lipid profiles. After adjustment for SES, age, and sex, the magnitude of differences in these CV markers was attenuated but remained statistically significant. Only LVMI differed by race in the glomerular CKD group, despite adjustment for SES.

LIMITATIONS

Study design limits causal inference.

CONCLUSION

African American children with CKD are disproportionately affected by socioeconomic disadvantages compared with White children. The degree to which CV markers differ by race is influenced by disease etiology. African Americans with nonglomerular CKD have increased LVMI, more ambulatory hypertension, and favorable lipid profile, but attenuation in magnitude after adjustment for SES was observed. African Americans with glomerular CKD had increased LVMI, which persisted after SES adjustment. As many social determinants of health were not captured, future research should examine effects of systemic racism on CV health in this population.

Association of Multiple Plasma Biomarker Concentrations with Progression of Prevalent Diabetic Kidney Disease: Findings from the Chronic Renal Insufficiency Cohort (CRIC) Study

BACKGROUND

Although diabetic kidney disease is the leading cause of ESKD in the United States, identifying those patients who progress to ESKD is difficult. Efforts are under way to determine if plasma biomarkers can help identify these high-risk individuals.

METHODS

In our case-cohort study of 894 Chronic Renal Insufficiency Cohort Study participants with diabetes and an eGFR of <60 ml/min per 1.73 m² at baseline, participants were randomly selected for the subcohort; cases were those patients who developed progressive diabetic kidney disease (ESKD or 40% eGFR decline). Using a multiplex system, we assayed plasma biomarkers related to tubular injury, inflammation, and fibrosis (KIM-1, TNFR-1, TNFR-2, MCP-1, suPAR, and YKL-40). Weighted Cox regression models related biomarkers to progression of diabetic kidney disease, and mixed-effects models estimated biomarker relationships with rate of eGFR change.

RESULTS

Median follow-up was 8.7 years. Higher concentrations of KIM-1, TNFR-1, TNFR-2, MCP-1, suPAR, and YKL-40 were each associated with a greater risk of progression of diabetic kidney disease, even after adjustment for established clinical risk factors. After accounting for competing biomarkers, KIM-1, TNFR-2, and YKL-40 remained associated with progression of diabetic kidney disease; TNFR-2 had the highest risk (adjusted hazard ratio, 1.61; 95% CI, 1.15 to 2.26). KIM-1, TNFR-1, TNFR-2, and YKL-40 were associated with rate of eGFR decline.

CONCLUSIONS

Higher plasma levels of KIM-1, TNFR-1, TNFR-2, MCP-1, suPAR, and YKL-40 were associated with increased risk of progression of diabetic kidney disease; TNFR-2 had the highest risk after accounting for the other biomarkers. These findings validate previous literature on TNFR-1, TNFR-2, and KIM-1 in patients with prevalent CKD and provide new insights into the influence of suPAR and YKL-40 as plasma biomarkers that require validation.

Longitudinal kidney injury biomarker trajectories in children with obstructive uropathy

BACKGROUND

Congenital obstructive uropathy (OU) is a leading cause of pediatric kidney failure, representing a unique mechanism of injury, in part from renal tubular stretch and ischemia. Tubular injury biomarkers have potential to improve OU-specific risk stratification.

METHODS

Patients with OU were identified in the Chronic Kidney Disease in Children (CKiD) study. "Cases" were defined as individuals receiving any kidney replacement therapy (KRT), while "controls" were age- and time-on-study matched and KRT free at last study visit. Urine and plasma neutrophil gelatinase-associated lipocalin (NGAL), interleukin 18 (IL-18), and liver-type fatty acid-binding protein (L-FABP) levels were measured at enrollment and annually and compared between cases and controls. Urine values were normalized to urine creatinine.

RESULTS

In total, 22 cases and 22 controls were identified, with median (interquartile range) ages of 10.5 (9.0-13.0) and 15.9 (13.9-16.9) years at baseline and outcome, respectively. At enrollment there were no differences noted between cases and controls for any urine (u) or plasma (p) biomarker measured. However, the mean pNGAL and uL-FABP/creatinine increased throughout the study period in cases (15.38 ng/ml per year and 0.20 ng/ml per mg/dl per year, respectively, p = 0.01 for both) but remained stable in controls. This remained constant after controlling for baseline glomerular filtration rate (GFR).

CONCLUSIONS

In children with OU, pNGAL and uL-FABP levels increased over the 5 years preceding KRT; independent of baseline GFR. Future studies are necessary to identify optimal cutoff values and to determine if these markers outperform current clinical predictors.