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Rationale & objectiveTubulointerstitial damage is a feature of early chronic kidney disease (CKD), but current clinical tests capture it poorly. Urine biomarkers of tubulointerstitial health may identify risk of CKD.Study designProspective cohort (Atherosclerosis Risk in Communities [ARIC]) and case-cohort (Multi-Ethnic Study of Atherosclerosis [MESA] and Reasons for Geographic and Racial Differences in Stroke [REGARDS]).Setting & participantsAdults with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 and without diabetes in the ARIC, REGARDS, and MESA studies.ExposuresBaseline urine monocyte chemoattractant protein-1 (MCP-1), alpha-1-microglobulin (α1m), kidney injury molecule-1, epidermal growth factor, and chitinase-3-like protein 1.OutcomeIncident CKD or end-stage kidney disease.Analytical approachMultivariable Cox proportional hazards regression for each cohort; meta-analysis of results from all 3 cohorts.Results872 ARIC participants (444 cases of incident CKD), 636 MESA participants (158 cases), and 924 REGARDS participants (488 cases) were sampled. Across cohorts, mean age ranged from 60 ± 10 to 63 ± 8 years, and baseline eGFR ranged from 88 ± 13 to 91 ± 14 mL/min/1.73 m2. In ARIC, higher concentrations of urine MCP-1, α1m, and kidney injury molecule-1 were associated with incident CKD. In MESA, higher concentration of urine MCP-1 and lower concentration of epidermal growth factor were each associated with incident CKD. In REGARDS, none of the biomarkers were associated with incident CKD. In meta-analysis of all 3 cohorts, each 2-fold increase α1m concentration was associated with incident CKD (HR, 1.19; 95% CI, 1.08-1.31).LimitationsObservational design susceptible to confounding; competing risks during long follow-up period; meta-analysis limited to 3 cohorts.ConclusionsIn 3 combined cohorts of adults without prevalent CKD or diabetes, higher urine α1m concentration was independently associated with incident CKD. 4 biomarkers were associated with incident CKD in at least 1 of the cohorts when analyzed individually. Kidney tubule health markers might inform CKD risk independent of eGFR and albuminuria.

Markers of glomerular disease, estimated glomerular filtration rate (eGFR) and albuminuria, are associated with cardiac structural abnormalities and incident cardiovascular disease (CVD). We aimed to determine whether biomarkers of kidney tubule injury, function, and systemic inflammation are associated with cardiac structural abnormalities. Among 393 Multi-Ethnic Study of Atherosclerosis participants without diabetes, CVD, or chronic kidney disease, we assessed the association of 12 biomarkers of kidney tubule injury, function, and systemic inflammation with the left ventricular mass/volume ratio (LVmvr) and left ventricular ejection fraction (LVEF) on cardiac magnetic resonance imaging using linear regression. The average age was 60 ± 10 years; 48% were men; mean eGFR was 96±16 ml/min/1.73 m2; mean LVmvr was 0.93±0.18 g/ml, and mean LVEF was 62±6%. Each twofold greater concentration of plasma soluble urokinase plasminogen activator receptor was associated with a 0.04 g/ml (95% confidence interval [CI] 0.01 to 0.08 g/ml) higher LVmvr and 2.1% (95% CI 0.6 to 3.5%) lower LVEF, independent of risk factors for CVD, eGFR, and albuminuria. Each twofold greater plasma monocyte chemoattractant protein 1 was associated with higher LVmvr with a similar coefficient to that of plasma soluble urokinase plasminogen activator receptor. Each twofold greater concentration of plasma chitinase-3-like protein 1 and urine alpha-1-microglobulin was associated with a 1.1% (95% CI 0.4 to 1.7%) and 1.2% (95% CI 0.2 to 2.2%) lower LVEF, respectively. In conclusion, abnormal kidney tubule health may lead to cardiac dysfunction above and beyond eGFR and albuminuria.

Background Uromodulin is the most abundant protein in the urine of healthy adults, and higher urine concentrations mark better tubular health. Greater kidney size and function are predictors of higher uromodulin levels in adults. Urine uromodulin has not yet been studied in children with chronic kidney disease (CKD). Thus, we sought to determine the relationship between age and kidney function with urine uromodulin levels in children with CKD. Methods In the CKD in Children (CKiD) cohort, we utilized multivariable linear regression to evaluate the relationship of age and eGFR with urine uromodulin levels. The primary outcome was uromodulin indexed to urine creatinine (Umod/Cr, mg/g), which was log.sub.2-transformed given its skewed distribution. Results Among 677 CKiD participants, the median age was 11.8 years (8.2-15.3), the median eGFR was 49 ml/min/1.73 m.sup.2 (37-63), the etiology of CKD was glomerular disease in 31%, and the median Umod/Cr level was 0.114 mg/g (0.045-0.226). In the multivariable models, each one-year older age was associated with 0.18 (12%) lower log.sub.2(Umod/Cr) and 0.20 (13%) lower log.sub.2(Umod/Cr) among those with non-glomerular and glomerular disease, respectively (p < 0.001). However, we did not find a statistically significant association between eGFR and Umod/Cr in either participants with non-glomerular or glomerular disease (p = 0.13 and p = 0.58, respectively). Conclusions Among children with CKD, older age is significantly associated with lower Umod/Cr, independent of eGFR. Further studies are needed to comprehensively evaluate age-specific reference ranges for urine uromodulin and to evaluate the longitudinal relationship of uromodulin with both age and eGFR in children with CKD. Graphical abstract, Author(s): Sophia C. Faulkner [sup.1] , Matthew B. Matheson [sup.2] , Jason H. Greenberg [sup.1] [sup.3] , Pranav S. Garimella [sup.4] , Susan L. Furth [sup.5] , Joachim H. Ix [...]

Background Immunization is essential in preventing life-threatening pneumococcal infections in children with nephrotic syndrome. An additional 23-valent pneumococcal polysaccharide vaccine (PPSV23) series is required for children with nephrotic syndrome. Despite current practice guidelines, many children with nephrotic syndrome do not receive PPSV23. Methods Our nephrology clinic conducted a quality improvement project to improve the overall rate of PPSV23 counseling to more than 70% within a 12-month period by applying several targeted interventions to raise providers' awareness, improve communication with primary care providers, and increase provider adherence. Data was collected from the electronic health record (EHR), and monthly performance was tracked via monthly control charts and overall immunization counseling rate charts. Results We increased adherence to PPSV23 vaccination counseling from a baseline of 12 to 86%. The first intervention that effectively increased the vaccine counseling rate from 12 to 30% was improving a provider's awareness of the PPSV23 literature and vaccine guidelines. Other interventions included regular performance reviews at division meetings, creating an immunization protocol, posting performance charts on the office bulletin board, and unifying vaccine recommendation templates. Lastly, specific and timely EHR reminders improved the total counseling rate from 52 to 86% and maintained adherence until the completion of the project. Conclusion Bridging the knowledge gap in provider awareness and using specific EHR reminders can improve adherence to PPSV23 counseling in children with nephrotic syndrome. Such interventions could be applied to similar groups of immunocompromised patients in whom additional vaccines are indicated. Graphical abstract, Author(s): Ibrahim Sandokji [sup.1] [sup.2] , Linda S. Anderson [sup.1] , Jillian K. Warejko [sup.1] , Beth L. Emerson [sup.3] , Jason H. Greenberg [sup.1] Author Affiliations: (1) grid.47100.32, 0000000419368710, [...]

Despite increasing prevalence of hypertension in youth and high adult cardiovascular mortality rates, the long-term consequences of youth-onset hypertension remain unknown. This is due to limitations of prior research, such as small sample sizes, reliance on manual record review, and limited analytic methods, that did not address major biases. The Study of the Epidemiology of Pediatric Hypertension (SUPERHERO) is a multisite, retrospective registry of youth evaluated by subspecialists for hypertension disorders. Sites obtain harmonized electronic health record data using standardized biomedical informatics scripts validated with randomized manual record review. Inclusion criteria are index visit for International Classification of Diseases, 10th Revision (ICD-10) code–defined hypertension disorder on or after January 1, 2015, and age < 19 years. We exclude patients with ICD-10 code–defined pregnancy, kidney failure on dialysis, or kidney transplantation. Data include demographics, anthropomorphics, US Census Bureau tract, histories, blood pressure, ICD-10 codes, medications, laboratory and imaging results, and ambulatory blood pressure. SUPERHERO leverages expertise in epidemiology, statistics, clinical care, and biomedical informatics to create the largest and most diverse registry of youth with newly diagnosed hypertension disorders. SUPERHERO's goals are to reduce CVD burden across the life course and establish gold-standard biomedical informatics methods for youth with hypertension disorders. [ABSTRACT FROM AUTHOR]

Author(s): James T. Nugent [sup.1] , Juliann Reardon [sup.1] , Christine Crana [sup.1] , Jason H. Greenberg [sup.1] , Jillian K. Warejko [sup.1] , Julie E. Goodwin [sup.1] Author Affiliations: [...]

Background Children undergoing cardiac surgery are at risk of high blood pressure (BP), a risk factor for cardiovascular and kidney disease. Twenty-four-hour ambulatory BP monitoring (ABPM) is a reference standard hypertension (HTN) test. Little data exist on ABPM abnormalities in children several years post cardiac surgery. This study aimed to (a) determine ABPM feasibility; (b) describe and compare ABPM measures and abnormalities (percent load, masked HTN [MH]; non-dipping, mean systolic/diastolic BP > 95th percentile; pre-HTN (ABPM); white-coat HTN [WCH]) to casual BP; and (c) compare BP in patients with and without acute kidney injury (AKI). Methods Prospective, follow-up pilot study of children (0-18 years) who underwent cardiac surgery from 2007 to 2009 at Montreal Children's Hospital. We recorded if participants had post-operative AKI and assessed the following outcomes at 9-year follow-up: casual BP classified by three single-visit measures (normal; elevated BP [eBP.sub.SingleVisit]; HTN.sub.SingleVisit); ABPM. Bivariable analyses were used to compare characteristics between groups. Results Twenty-three patients (median [interquartile range], 8.6 [8.0, 9.0] years post cardiac surgery) were included; 16 (70%) male. Six participants (26%) had eBP.sub.SingleVisit or higher. On ABPM, 11 (48%) had [greater than or equal to] 1 abnormality: 9 (39%) had non-dipping; 3 (13%) had pre-HTN; 3 (13%) had WCH; none had HTN or MH. There were no differences in ABPM according to AKI status. Conclusion Our pilot study determined that ABPM was feasible in children years after cardiac surgery and frequently identified ABPM abnormalities. Future research in larger populations is needed to define specific risk factors for HTN in children after cardiac surgery., Author(s): Daniel Fredric [sup.1] , Jason H. Greenberg [sup.2] , Chirag R. Parikh [sup.3] , Prasad Devarajan [sup.4] , Hayton Chui [sup.1] , Vedran Cockovski [sup.1] , Michael Pizzi [sup.5] [...]

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., Author(s): Daryl J. McLeod [sup.1] [sup.2] , Yuri V. Sebastião [sup.2] , Christina B. Ching [sup.1] [sup.3] , Jason H. Greenberg [sup.4] , Susan L. Furth [sup.5] , Brian Becknell [...]

The article presents the discussion on case study of 16-year-old male with no significant past medical history was referred to our pediatric nephrology clinic for high blood pressure detected by his primary care pediatrician. Topics include clinicians order this study for all children and adolescents with hypertension, particularly in the subspecialty setting; and diagnostic yield of kidney ultrasound in the evaluation of children and adolescents with hypertension.

Background Obstructive uropathy (OU) is a common cause of end-stage renal disease (ESRD) in children. Children who escape the newborn period with mild-to-moderate chronic kidney disease (CKD) continue to be at increased risk. The predictive ability of clinically available markers throughout childhood is poorly defined. Methods Patients with OU were identified in the Chronic Kidney Disease in Children Study. The primary outcome of interest was renal replacement therapy (RRT) (cases). Controls were age matched and defined as patients within the OU cohort who did not require RRT during study follow-up. Results In total, 27 cases and 41 age-matched controls were identified. Median age at baseline and age at outcome measurement were 10 vs. 16 years, respectively. First available glomerular filtration rate (GFR) (36.9 vs. 53.5 mL/min per 1.73 m.sup.2), urine protein/creatinine (Cr) (0.40 vs. 0.22 mg/mg) and microalbumin/Cr (0.58 vs. 0.03 mg/mg), and serum CO.sub.2 (20 vs. 22 mmol/L) and hemoglobin (12.4 vs. 13.2 g/dL) differed significantly between cases and controls, respectively. GFR declined 3.07 mL/min per 1.73 m.sup.2/year faster in cases compared to that in controls (p < 0.0001). Urine protein/Cr and microalbumin/Cr increased by 0.16 and 0.11 per year more in cases compared to those in controls, respectively (p [less than or equal to] 0.001 for both). Serum phosphate increased by 0.11 mg/dL and serum albumin and hemoglobin decreased by 0.04 (g/dL) and 0.14 (g/dL) per year more for cases compared to those for controls, respectively (p < 0.05 for all). Conclusions Age-specific baseline and longitudinal measures of readily available clinical measures predict progression to ESRD in children with mild-to-moderate CKD from OU., Author(s): Daryl J. McLeod [sup.1] [sup.2] , Christina B. Ching [sup.1] [sup.3] , Yuri V. Sebastião [sup.2] , Jason H. Greenberg [sup.4] , Susan L. Furth [sup.5] , Kirk M. [...]

Chronic kidney disease (CKD) has become a significant public health concern, as it is associated with substantial morbidity. Prior research has evaluated multiple novel CKD biomarkers to supplement serum creatinine and proteinuria. The ultimate goal of this research is to find biomarkers that can be used to accurately predict CKD progression and to better time outpatient follow-up, and referral for transplant. Also, an optimal panel of biomarkers can augment the predictive value of proteinuria and serum creatinine by enriching patient enrollment in clinical trials. In this review, we discuss salient findings on 12 candidate plasma and urine biomarkers and their reported association with CKD. We explore the common pathways of CKD progression and the pathophysiologic processes of tubulointerstitial injury, inflammation, repair, and fibrosis that are potentially classified by specific biomarkers. We describe both pediatric and adult findings and highlight the paucity of pediatric research in CKD progression. It will be important for cohorts with longitudinal follow-up to evaluate these CKD biomarkers for potential use in pediatric clinical trials and routine CKD management., Author(s): Jason H. Greenberg [sup.1] [sup.2] , Aadil Kakajiwala [sup.3] , Chirag R. Parikh [sup.2] [sup.4] [sup.5] , Susan Furth [sup.3] Author Affiliations: (Aff1) 0000000419368710, grid.47100.32, Department of Pediatrics, Section [...]

Background We previously reported that children undergoing cardiac surgery are at high risk for long-term chronic kidney disease (CKD) and hypertension, although postoperative acute kidney injury (AKI) is not a risk factor for worse long-term kidney outcomes. We report here our evaluation of renal injury biomarkers 5 years after cardiac surgery to determine whether they are associated with postoperative AKI or long-term CKD and hypertension. Methods Children aged 1 month to 18 years old undergoing cardiopulmonary bypass were recruited to this prospective cohort study. At 5 years after cardiac surgery, we measured urine interleukin-18, kidney injury molecule-1, monocyte chemoattractant protein-1, YKL-40, and neutrophil gelatinase-associated lipocalin (NGAL). Biomarker levels were compared between patients with AKI and those without. We also performed a cross-sectional analysis of the association between these biomarkers with CKD and hypertension. Results Of the 305 subjects who survived hospitalization, four (1.3%) died after discharge, and 110 (36%) participated in the 5-year follow-up. Of these 110 patients, 49 (45%) had AKI. Patients with versus those without postoperative AKI did not have significantly different biomarker concentrations at 5 years after cardiac surgery. None of the biomarker concentrations were associated with CKD or hypertension at 5 years of follow-up, although CKD and hypertension were associated with a higher proportion of participants with abnormal NGAL levels. Conclusions Postoperative pediatric AKI is not associated with urinary kidney injury biomarkers 5 years after surgery. This may represent a lack of chronic renal injury after AKI, imprecise estimation of the glomerular filtration rate, the need for longer follow-up to detect chronic renal damage, or that our studied biomarkers are inadequate for evaluating subclinical chronic renal injury., Author(s): Jason H. Greenberg [sup.1] [sup.2] , Prasad Devarajan [sup.3] , Heather R. Thiessen-Philbrook [sup.2] , Catherine Krawczeski [sup.4] , Chirag R. Parikh [sup.2] [sup.5] [sup.6] , Michael Zappitelli [sup.7] [...]