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Background Obesity is prevalent among children with chronic kidney disease (CKD) and is associated with cardiovascular disease and reduced quality of life. Its relationship with pediatric CKD progression has not been described. Methods We evaluated relationships between both body mass index (BMI) category (normal, overweight, obese) and BMI z-score (BMIz) change on CKD progression among participants of the Chronic Kidney Disease in Children study. Kaplan-Meier survival curves and multivariable parametric failure time models depict the association of baseline BMI category on time to kidney replacement therapy (KRT). Additionally, the annualized percentage change in estimated glomerular filtration rate (eGFR) was modeled against concurrent change in BMIz using multivariable linear regression with generalized estimating equations which allowed for quantification of the effect of BMIz change on annualized eGFR change. Results Participants had median age of 10.9 years [IQR: 6.5, 14.6], median eGFR of 50 ml/1.73 m.sup.2 [IQR: 37, 64] and 63% were male. 160 (27%) of 600 children with non-glomerular and 77 (31%) of 247 children with glomerular CKD progressed to KRT over a median of 5 years [IQR: 2, 8]. Times to KRT were not significantly associated with baseline BMI category. Children with non-glomerular CKD who were obese experienced significant improvement in eGFR (+ 0.62%; 95% CI: + 0.17%, + 1.08%) for every 0.1 standard deviation concurrent decrease in BMI. In participants with glomerular CKD who were obese, BMIz change was not significantly associated with annualized eGFR change. Conclusion Obesity may represent a target of intervention to improve kidney function in children with non-glomerular CKD. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information, Author(s): Amy J. Kogon [sup.1] , Jennifer Roem [sup.2] , Michael F. Schneider [sup.2] , Mark M. Mitsnefes [sup.3] , Babette S. Zemel [sup.4] , Bradley A. Warady [sup.5] , [...]

Background Elevated serum uric acid concentration is a risk factor for CKD progression. Its change over time and association with CKD etiology and concomitant changes in estimated glomerular filtration rate (eGFR) in children and adolescents are unknown. Methods Longitudinal study of 153 children/adolescents with glomerular (G) and 540 with non-glomerular (NG) etiology from the CKD in Children (CKiD) study. Baseline serum uric acid, change in uric acid and eGFR over time, CKD etiology, and comorbidities were monitored. Adjusted linear mixed-effects regression models quantified the relationship between within-person changes in uric acid and concurrent within-person changes in eGFR. Results Participants with stable uric acid over follow-up had CKD progression which became worse for increased baseline uric acid (average annual percentage changes in eGFR were - 1.4%, - 7.7%, and - 14.7% in those with G CKD with baseline uric acid 7.5 mg/dL, respectively; these changes were - 1.4%, - 4.1%, and - 8.6% in NG CKD). Each 1 mg/dL increase in uric acid over follow-up was independently associated with significant concomitant eGFR decreases of - 5.7% (95%CI - 8.4 to - 3.0%) (G) and - 5.1% (95%CI - 6.3 to - 4.0%) (NG) for those with baseline uric acid < 5.5 mg/dL and - 4.3% (95%CI - 6.8 to - 1.6%) (G) and - 3.3% (95%CI - 4.1 to - 2.6%) (NG) with baseline uric acid between 5.5 and 7.5 mg/dL. Conclusions Higher uric acid levels and increases in uric acid over time are risk factors for more severe progression of CKD in children and adolescents. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information., Author(s): George J. Schwartz [sup.1] , Jennifer L. Roem [sup.2] , Stephen R. Hooper [sup.3] , Susan L. Furth [sup.4] , Donald J. Jr. Weaver [sup.5] , Bradley A. Warady [...]

Rationale & objectiveChronic kidney disease (CKD) in children is associated with cognitive dysfunction that affects school performance and quality of life. The relationship between CKD-mineral and bone disorder and cognitive function in children is unknown.Study designObservational study.Participants702 children enrolled in the Chronic Kidney Disease in Children (CKiD) Study.PredictorsPlasma fibroblast growth factor 23 (FGF-23), parathyroid hormone (PTH), calcium, phosphorus, 25 hydroxyvitamin D (25[OH]D), and 1,25 dihydroxyvitamin D (1,25[OH]2D).OutcomesNeurocognitive tests of intelligence, academic achievement, and executive functions.Analytical approachLinear regression models to analyze the cross-sectional associations between log2FGF-23, 25(OH)D, 1,25(OH)2D, PTH, calcium, and phosphorus z scores and the cognitive test scores of interest after adjustment for demographics, blood pressure, proteinuria, and kidney function.ResultsAt baseline, median age was 12 (95% CI, 8.3, 15.2) years and estimated glomerular filtration rate was 54 (40.5, 67.8) mL/min/1.73 m2. In fully adjusted analyses, 25(OH)D, 1,25(OH)2D, PTH, calcium, and phosphorus z scores did not associate with cognitive test scores. In fully adjusted analyses, log2FGF-23 was associated with abnormal test scores for attention regulation (P

Background Vegetable or plant-based sources of protein may confer health benefits in children with progressive kidney disease. Our aims were to understand the effect of the proportion of vegetable protein intake on changes in estimated GFR and to understand the effect of the proportion of vegetable protein intake on serum levels of bicarbonate, phosphorus, and potassium. Methods Children with baseline eGFR between 30 and 90 mL/min/1.73 m.sup.2 were recruited from 59 centers across North America as part of the chronic kidney disease in children (CKiD) study. The percentage of dietary vegetable protein (VP%) was gathered from annual Food Frequency Questionnaires. We performed longitudinal linear mixed models to determine the effect of VP% on eGFR and longitudinal logistic mixed models to determine the effect of VP% on electrolyte balance (potassium, phosphorus, bicarbonate). Results Two thousand visits from 631 subjects. Across all dichotomized groups of children (sex, African American race, Hispanic ethnicity, glomerular etiology of CKD, hypertension, anemia, hyperkalemia, hyperphosphatemia, acidosis, BMI < 95th percentile), the median VP% was 32-35%. The longitudinal mixed model analysis did not show any effect of VP% on eGFR electrolyte (bicarbonate, phosphorus, and potassium) abnormalities (p > 0.1). Conclusions A diverse cohort of children with CKD has a narrow and homogeneous intake of vegetable protein. Due to the low variability of plant-based protein in the cohort, there were no associations between the percentage of plant protein intake and changes in eGFR nor electrolyte balance., Author(s): Lokesh N. Shah [sup.1] [sup.2] , Matthew B. Matheson [sup.3] , Susan L. Furth [sup.4] [sup.5] , George J. Schwartz [sup.6] , Bradley A. Warady [sup.7] [sup.8] , Cynthia [...]

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.sup.th percentile), and GFR was 44 ml/min/1.73m.sup.2. They were compared to 106 children with growth failure who never initiated therapy (8.8 years, -2.33 SDs, and 51 ml/min/1.73m.sup.2). 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., Author(s): Derek K. Ng [sup.1] , Megan K. Carroll [sup.1] , Frederick J. Kaskel [sup.2] , Susan L. Furth [sup.3] [sup.4] , Bradley A. Warady [sup.5] , Larry A. Greenbaum [...]

Background Chronic kidney disease (CKD) is associated with many comorbidities requiring complex management. We described treatment patterns for common modifiable CKD complications (high blood pressure, anemia, hyperphosphatemia, and acidosis) according to severity of CKD and examined factors associated with the absence of drug therapy, among participants with a persistent comorbidity, for 1 year in children enrolled in the CKiD study. Methods A total of 703 CKiD participants contributed 2849 person-visits over a median 3.5 years of follow-up. Using pairs of annual visits, we examined whether participants with abnormal biomarker levels at the first (index) visit persisted in the abnormal levels 1 year later according to CKD risk stage. Multivariate analyses identified demographic and clinical factors associated with the absence of drug therapy among those with persistent comorbid conditions for 1 year. Results The overall proportions of person-visits prescribing therapy at 1-year follow-up for treating anemia, acidosis, hyperphosphatemia, and high blood pressure were 54%, 45%, 29%, and 81%, respectively. The frequency of therapy increased with advanced CKD risk stage for all comorbidities; however, 19-23% of participants with acidosis, 24-27% with anemia, and 30-39% with hyperphosphatemia at high-risk stages (E and F) were not prescribed appropriate therapy despite the persistence of abnormal levels of these biomarkers for at least 1 year. The resolution of comorbidities at advanced CKD stages without treatment was unlikely. Conclusions Many children with CKD in the CKiD cohort did not receive pharmacological treatment for common and persistent modifiable comorbidities, even in severe CKD risk stages. Graphical abstract, Author(s): Yunwen Xu [sup.1] , Derek K Ng [sup.1] , Susan L Furth [sup.2] , Bradley A Warady [sup.3] , Mark M Mitsnefes [sup.4] Author Affiliations: (1) grid.21107.35, 0000 0001 [...]

BackgroundAnorexia and malnutrition are associated with poor outcomes in children with chronic kidney disease (CKD).Study designObservational cohort study.Setting & participantsWe assessed changes in body mass index (BMI) as kidney function declines and its association with risk for end-stage renal disease (ESRD) among 854 participants followed between 2005 to 2013 in the CKD in Children (CKiD) Study.PredictorsRepeated measurements of estimated glomerular filtration rate (eGFR) by serum creatinine concentration in our trajectory analysis using mixed models; change in BMI z score (per year) after eGFR decreased to  0.2 per year) after eGFR decreased to

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 [greater than or equal to]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., Author(s): Andrea R. Molino [sup.1] , Judith Jerry-Fluker [sup.1] , Meredith A. Atkinson [sup.2] , Susan L. Furth [sup.3] , Bradley A. Warady [sup.4] , Derek K. Ng [sup.1] Author [...]

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., Author(s): Kelsey L. Richardson [sup.1] , Donald J. Jr Weaver [sup.2] , Derek K. Ng [sup.3] , Megan K. Carroll [sup.3] , Susan L. Furth [sup.4] , Bradley A. Warady [...]

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 [greater than or equal to] 90th percentile were studied. BP categories were defined as the maximum systolic or diastolic BP percentile (< 50th, 50th to 75th, 75th to 90th, and [greater than or equal to] 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 [greater than or equal to] 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., Author(s): Joseph T. Flynn [sup.1] [sup.2] , Megan K. Carroll [sup.3] , Derek K. Ng [sup.3] , Susan L. Furth [sup.4] [sup.5] , Bradley A. Warady [sup.6] Author Affiliations: (1) [...]

Introduction The number of medications could serve as a surrogate for burden of care at home and may affect health-related quality of life (HRQoL) in children with chronic kidney disease (CKD). Methods Using baseline data from the Chronic Kidney Disease in Children (CKiD) Study, we modeled HRQoL scores, self-reported by the child (if [greater than or equal to] 8 years old) and/or caregiver (all children) on unique counts and administrations of CKD- and non-CKD-related medications, using multivariate linear regression. Heterogeneity of associations between HRQoL and medication burden by age group ([greater than or equal to] 8 vs. < 8 years old) were explored. Results 734 participants median age 11 years, disease duration 8 years, median eGFR 53 mL/min/1.73 m.sup.2, 61% male, 22% African-American, 31% glomerular disease were prescribed median 3 unique CKD-related medications. Regarding HRQoL assessment, 201 children were < 8 years old and had only parent-proxy HRQoL score; 533 children [greater than or equal to] 8 years of age had both child and parent-proxy scores. Overall, parents of children < 8 years old reported higher HRQoL scores than parents of older children: 84 vs. 76. However, in a unified multivariate regression model, HRQoL scores of children < 8 years showed greater decreases as the number of CKD-related medications increased compared to scores for children [greater than or equal to] 8 years old. Conclusion Average HRQoL scores reported by parents of younger CKD children were higher than those of older CKD children but decreased more with increased CKD medication counts than scores of older children. Considerations of HRQoL may be of particular importance for clinicians and caregivers when managing chronic disease comorbidities in younger children., Author(s): Maria E. Díaz-González de Ferris [sup.1] , Chris B. Pierce [sup.2] , Debbie S. Gipson [sup.3] , Susan L. Furth [sup.4] , Bradley A. Warady [sup.5] , Stephen R. [...]

PurposeWe determined the association between dietary zinc intake and incident calcium kidney stones in adolescents. We also examined the relationship between dietary zinc intake and urinary zinc excretion between cases and controls.Materials and methodsWe conducted a nested case-control study within a large pediatric health care system. Three 24-hour dietary recalls and spot urine chemistry analyses were obtained for 30 participants 12 to 18 years old with a first idiopathic calcium based kidney stone and 30 healthy controls matched for age, sex, race and month of enrollment. Conditional logistic regression models were used to estimate the association between daily zinc intake and incident calcium kidney stones, adjusting for dietary phytate, protein, calcium, sodium and oxalate. Multivariable linear regression was used to estimate the association between dietary and urine zinc, adjusting for urine creatinine and dietary phytate and calcium.ResultsCases had lower daily zinc intake (8.1 mg) than controls (10 mg, p = 0.029). Daily zinc intake of boys and girls with calcium stones was 2 mg and 1.2 mg less, respectively, than the daily intake recommended by the Institute of Medicine. Odds of incident stones were reduced by 13% for every 1 mg increase in daily zinc intake (OR 0.87, 95% CI 0.75-0.99). There was an estimated 4.5 μg/dl increase in urine zinc for every 1 mg increase in dietary zinc (p = 0.009), with weak evidence of a smaller increase in urine zinc in cases than in controls (interaction p = 0.08).ConclusionsDecreased dietary zinc intake was independently associated with incident calcium nephrolithiasis in this population of adolescents.