Advocating for the inclusion of kidney health outcomes in neonatal research: best practice recommendations by the Neonatal Kidney Collaborative.

Acute kidney injury (AKI) occurs in nearly 30% of sick neonates. Chronic kidney disease (CKD) can be detected in certain populations of sick neonates as early as 2 years. AKI is often part of a multisystem syndrome that negatively impacts developing organs resulting in short- and long-term pulmonary, neurodevelopmental, and cardiovascular morbidities. It is critical to incorporate kidney-related data into neonatal clinical trials in a uniform manner to better understand how neonatal AKI or CKD could affect an outcome of interest. Here, we provide expert opinion recommendations and rationales to support the inclusion of short- and long-term neonatal kidney outcomes using a tiered approach based on study design: (1) observational studies (prospective or retrospective) limited to data available within a center's standard practice, (2) observational studies involving prospective data collection where prespecified kidney outcomes are included in the design, (3) interventional studies with non-nephrotoxic agents, and (4) interventional studies with known nephrotoxic agents. We also provide recommendations for biospecimen collection to facilitate ancillary kidney specific research initiatives. This approach balances the costs of AKI and CKD ascertainment with knowledge gained. We advocate that kidney outcomes be included routinely in neonatal clinical study design. Consistent incorporation of kidney outcomes across studies will increase our knowledge of neonatal morbidity.

Reduced kidney function and hypertension in adolescents with low birth weight, NHANES 1999-2016.

BACKGROUND: Chronic kidney disease (CKD) is a major health problem, and the risk of CKD and hypertension in children born low birth weight (LBW) is under-recognized. We hypothesized that children born with LBW would have a higher prevalence of reduced kidney function and hypertension. METHODS: Using the National Health and Nutrition Examination Survey (NHANES), we conducted a cross-sectional study to evaluate whether LBW (< 2500 g), very low birth weight (VLBW < 1500 g), and large birth weight (BW) (> 4000 g) were associated with kidney disease using 4 different estimating equations. We used the Counahan-Barratt, updated Schwartz, CKiD-U25, and full age spectrum creatinine-based GFR estimating equations to evaluate associations between a history of LBW/VLBW/large BW and reduced kidney function (eGFR < 90 mL/min/1.73 m2) in children. We also assessed blood pressure (BP) using the old and new pediatric hypertension guidelines. RESULTS: Our analysis included 6336 children (age 12-15 years) in NHANES representing over 13 million US individuals. Using the updated Schwartz, the prevalence of reduced kidney function was 30.1% (25.2-35.6) for children born with LBW compared to 22.4% (20.5-24.3) in children with normal BW. Equations yielded different estimates of prevalence of reduced kidney function in LBW from 21.5% for Counahan-Barratt to 35.4% for CKiD-U25. Compared to those with normal BW, participants with LBW and VLBW had a 7.2 and 10.3% higher prevalence of elevated BP and a 2.4 and 14.6% higher prevalence of hypertension, respectively. CONCLUSIONS: Children born with LBW are at higher risk of reduced kidney function and hypertension than previously described. A higher resolution version of the Graphical abstract is available as Supplementary information.

Associations of Dysnatremia with COVID-19 Status and Mortality.

Background: In patients without COVID-19, dysnatremia is associated with mortality. These relationships are not well established in patients with COVID-19. We tested the hypotheses that patients with COVID-19 were more likely to have dysnatremia than those without COVID-19 and that, among those with COVID-19, dysnatremia is associated with mortality. Methods: We conducted a retrospective observational study of patients admitted to a tertiary care center in the Bronx, New York, during the COVID-19 surge from March 11 to April 26, 2020. Using multinomial logistic regression models, we compared the prevalence of hypernatremia (serum sodium ≥150 mEq/L) and hyponatremia (serum sodium <130 mEq/L) on admission between patients with and without COVID-19. Among patients with COVID-19, we used Cox proportional hazards models to examine the association of dysnatremia with mortality. Results: Compared with those without COVID-19 (n=1265), patients with COVID-19 (n=3345) had a higher prevalence of hypernatremia (7% versus 4%, P<0.001) and hyponatremia (7% versus 6%, P=0.04). In adjusted models, COVID-19-positive patients had a higher likelihood of having hypernatremia (adjusted odds ratio=1.87, 95% CI, 1.3 to 2.57, P=0.001) compared with COVID-19-negative patients, whereas the association between hyponatremia and COVID-19 status was no longer significant (P=0.06). Among patients with COVID-19, 775 (23%) died after a median follow-up of 17 days (IQR 7-27 days). Among nonsurvivors, 15% had hypernatremia and 8% had hyponatremia on admission. Hypernatremia was associated with a higher risk of mortality (adjusted hazard ratio=1.28, 95% CI, 1.01 to 1.63, P=0.04) compared with patients with eunatremia. Conclusions: In patients hospitalized during the spring 2020 COVID-19 surge, COVID-19 status was associated with hypernatremia on admission. Among patients with COVID-19, hypernatremia was associated with higher mortality. Hypernatremia may be a potential prognostic marker for mortality in COVID-19 patients.

Association of GSTM1 Deletion With Progression of CKD in Children: Findings From the Chronic Kidney Disease in Children (CKiD) Study.

RATIONALE & OBJECTIVE: Loss of function of the product of the GSTM1 gene has been implicated in rapid progression of adult chronic kidney disease (CKD). Its role in pediatric CKD has not been previously described. STUDY DESIGN: Secondary analysis of a prospective observational cohort examining the association between deletions in GSTM1 and progression of CKD. SETTING & PARTICIPANTS: We used data and samples from the prospective Chronic Kidney Disease in Children (CKiD) cohort aged 1-16 years at enrollment with CKD. EXPOSURE: We defined the exposure as fewer than 2 GSTM1 alleles on real-time polymerase chain reaction amplification. OUTCOME: The primary outcome was a composite of 50% decrease in estimated glomerular filtration rate (eGFR) or start of kidney replacement therapy. Secondary outcomes included remission of proteinuria in children with glomerular disease and cardiovascular complications. ANALYTICAL APPROACH: The primary analysis was by Cox proportional hazards model. Analysis was adjusted for age, sex, race, ethnicity, body mass index category, diagnosis category, and eGFR. RESULTS: The analysis included 674 children. Their mean age at most recent visit was 11.9 years; 61% were male, and 20% were Black. There were 241 occurrences of the primary outcome at the time of analysis. After adjustment for baseline characteristics, the risk of progression of CKD for exposed children was 1.94 (95% CI, 1.27-2.97). The effect size was similar with either 1 or 2 deletions (autosomal dominant inheritance). The relationships between number of functional GSTM1 alleles and prespecified secondary outcomes were not statistically significant after adjustment. LIMITATIONS: Missing data, especially for secondary outcomes, and relatively small sample size compared to genetic studies in adults. CONCLUSIONS: GSTM1 deletion is associated with more rapid progression of pediatric CKD after adjustment in this large prospective cohort. No statistically significant associations were seen with secondary outcomes. If replicated, these findings may inform development of interventions for CKD in children.

Acute Postinfectious Glomerulonephritis.

Postinfectious glomerulonephritis (PIGN) is a leading cause of acute glomerulonephritis in children. The presentation of PIGN can vary from asymptomatic microscopic hematuria incidentally detected on routine urinalysis to nephritic syndrome and a rapidly progressive glomerulonephritis. Treatment involves supportive care with salt and water restriction, and the use of diuretic and/or antihypertensive medication, depending on the severity of fluid retention and the presence of hypertension. PIGN resolves completely and spontaneously in most children, and the long-term outcomes are typically good with preserved renal function and no recurrence.

Association of early dysnatremia with mortality in the neonatal intensive care unit: results from the AWAKEN study.

OBJECTIVE: To determine the association of dysnatremia in the first postnatal week and risk of acute kidney injury (AKI) and mortality. STUDY DESIGN: A secondary analysis of 1979 neonates in the AWAKEN cohort evaluated the association of dysnatremia with (1) AKI in the first postnatal week and (2) mortality, utilizing time-varying Cox proportional hazard models. RESULT: Dysnatremia developed in 50.2% of the cohort and was not associated with AKI. Mortality was associated with hyponatremia (HR 2.15, 95% CI 1.07-4.31), hypernatremia (HR 4.23, 95% CI 2.07-8.65), and combined hypo/hypernatremia (HR 6.39, 95% CI 2.01-14.01). In stratified models by AKI-status, hypernatremia and hypo/hypernatremia increased risk of mortality in neonates without AKI. CONCLUSION: Dysnatremia within the first postnatal week was associated with increased risk of mortality. Hypernatremia and combined hypo/hypernatremia remained significantly associated with mortality in neonates without AKI. This may reflect fluid strategies kidney injury independent of creatinine and urine-output defined AKI, and/or systemic inflammation.

Premature differentiation of nephron progenitor cell and dysregulation of gene pathways critical to kidney development in a model of preterm birth.

Preterm birth is a leading cause of neonatal morbidity. Survivors have a greater risk for kidney dysfunction and hypertension. Little is known about the molecular changes that occur in the kidney of individuals born preterm. Here, we demonstrate that mice delivered two days prior to full term gestation undergo premature cessation of nephrogenesis, resulting in a lower glomerular density. Kidneys from preterm and term groups exhibited differences in gene expression profiles at 20- and 27-days post-conception, including significant differences in the expression of fat-soluble vitamin-related genes. Kidneys of the preterm mice exhibited decreased proportions of endothelial cells and a lower expression of genes promoting angiogenesis compared to the term group. Kidneys from the preterm mice also had altered nephron progenitor subpopulations, early Six2 depletion, and altered Jag1 expression in the nephrogenic zone, consistent with premature differentiation of nephron progenitor cells. In conclusion, preterm birth alone was sufficient to shorten the duration of nephrogenesis and cause premature differentiation of nephron progenitor cells. These candidate genes and pathways may provide targets to improve kidney health in preterm infants.

Racial-ethnic differences in health-related quality of life among adults and children with glomerular disease.

INTRODUCTION: Disparities in health-related quality of life (HRQOL) have been inadequately studied in patients with glomerular disease. The aim of this study was to identify relationships between race/ethnicity, socioeconomic status, disease severity, and HRQOL in an ethnically and racially diverse cohort of patients with glomerular disease. METHODS: Cure Glomerulonephropathy (CureGN) is a multinational cohort study of patients with biopsy-proven glomerular disease. Associations between race/ethnicity and HRQOL were determined by the following: 1. Missed school or work due to kidney disease; 2. Responses to Patient Reported Outcomes Measurement Information System (PROMIS) questionnaires. We adjusted for demographics, socioeconomic status, and disease characteristics using multivariable logistic and linear regression. RESULTS: Black and Hispanic participants had worse socioeconomic status and more severe glomerular disease than White or Asian participants. Black adults missed work or school most frequently due to kidney disease (30% versus 16-23% in the other three groups, p=0.04), and had the worst self-reported global physical health (median score 44.1 versus 48.0-48.2, p<0.001) and fatigue (53.8 versus 48.5-51.1, p=0.002), compared to other racial/ethnic groups. However, these findings were not statistically significant with adjustment for socioeconomic status and disease severity, both of which were strongly associated with HRQOL in adults. Among children, disease severity but not race/ethnicity or socioeconomic status were associated with HRQOL. CONCLUSIONS: Among patients with glomerular disease enrolled in CureGN, the worse HRQOL reported by Black adults was attributable to lower socioeconomic status and more severe glomerular disease. No racial/ethnic differences in HRQOL were observed in children.

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.

Joint Associations of Maternal-Fetal APOL1 Genotypes and Maternal Country of Origin With Preeclampsia Risk.

RATIONALE & OBJECTIVES: Preeclampsia, which disproportionately affects Black women, is a leading cause of preterm delivery and risk for future hypertension and chronic kidney disease (CKD). Apolipoprotein L1 (APOL1) kidney risk alleles, common among Black individuals, contribute substantially to CKD disparities. Given the strong link between preeclampsia and CKD, we investigated whether maternal and fetal APOL1 risk alleles can jointly influence preeclampsia risk, and explored potential modifiers of the association between APOL1 and preeclampsia. STUDY DESIGN: Nested case-control study. SETTING & PARTICIPANTS: 426 Black mother-infant pairs (275 African Americans and 151 Haitians) from the Boston Birth Cohort. EXPOSURE: Maternal and fetal APOL1 risk alleles. OUTCOMES: Preeclampsia. ANALYTICAL APPROACH: Logistic regression models with adjustment for demographic characteristics were applied to analyze associations between fetal and maternal APOL1 risk alleles and risk of preeclampsia and to investigate the effects of modification by maternal country of origin. RESULTS: Fetal APOL1 risk alleles tended to be associated with an increased risk of preeclampsia, which was not statistically significant in the total genotyped population. However, this association was modified by maternal country of origin (P<0.05 for interaction tests): fetal APOL1 risk alleles were significantly associated with an increased risk of preeclampsia among African Americans under recessive (odds ratio [OR], 3.6 [95% CI, 1.3-9.7]; P=0.01) and additive (OR, 1.7 [95% CI, 1.1-2.6]; P=0.01) genetic models but not in Haitian Americans. Also, maternal-fetal genotype discordance at the APOL1 locus was associated with a 2.6-fold higher risk of preeclampsia (P<0.001) in African Americans. LIMITATIONS: Limited sample size in stratified analyses; self-reported maternal country of origin; pre-pregnancy estimated glomerular filtration rate (eGFR) and proteinuria data in mothers were not collected; unmeasured confounding social and/or environmental factors; no replication study. CONCLUSIONS: This study supports the hypothesis that fetal APOL1 kidney risk alleles are associated with increased risk for preeclampsia in a recessive mode of inheritance in African Americans and suggests that maternal-fetal genotype discordance is also associated with this risk. These conclusions underscore the need to better understand maternal-fetal interaction and their genetic and environmental factors as contributors to ethnic disparities in preeclampsia.

COVID-19 in Children With Kidney Disease: A Report of 2 Cases.

The presentation of novel coronavirus disease 2019 (COVID-19) in children with kidney disease is largely unknown. We report on 2 children with kidney disease not receiving long-term immunosuppression who were hospitalized due to COVID-19. The first case is an infant with end-stage kidney disease secondary to bilateral cystic dysplastic kidneys and posterior urethral valves receiving peritoneal dialysis, with a history of prematurity previously requiring mechanical ventilation in the neonatal intensive care unit, who presented with fever, hypertension, and emesis. He had no respiratory symptoms and recovered with supportive care. His hypertension was managed well with amlodipine. The second case is a child with steroid-sensitive nephrotic syndrome who presented with a relapse of nephrotic syndrome with concurrent peritonitis and sepsis caused by Streptococcus agalactiae. He was treated with antibiotics and prophylactic anticoagulation therspy. Steroid therapy was initiated after 48 hours of antibiotic therapy. Neither child required mechanical ventilation or developed COVID-19-related multisystem inflammatory syndrome.

The longitudinal relationship between patient-reported outcomes and clinical characteristics among patients with focal segmental glomerulosclerosis in the Nephrotic Syndrome Study Network.

BACKGROUND: Understanding the relationship between clinical and patient-reported outcomes (PROs) will help support clinical care and future clinical trial design of novel therapies for focal segmental glomerulosclerosis (FSGS). METHODS: FSGS patients ≥8 years of age enrolled in the Nephrotic Syndrome Study Network completed Patient-Reported Outcomes Measurement Information System PRO measures of health-related quality of life (HRQoL) (children: global health, mobility, fatigue, pain interference, depression, anxiety, stress and peer relationships; adults: physical functioning, fatigue, pain interference, sleep impairment, mental health, depression, anxiety and social satisfaction) at baseline and during longitudinal follow-up for a maximum of 5 years. Linear mixed-effects models were used to determine which demographic, clinical and laboratory features were associated with PROs for each of the eight children and eight adults studied. RESULTS: There were 45 children and 114 adult FSGS patients enrolled that had at least one PRO assessment and 519 patient visits. Multivariable analyses among children found that edema was associated with global health (-7.6 points, P = 0.02) and mobility (-4.2, P = 0.02), the number of reported symptoms was associated with worse depression (-2.7 per symptom, P = 0.009) and anxiety (-2.3, P = 0.02) and the number of emergency room (ER) visits in the prior 6 months was associated with worse mobility (-2.8 per visit, P < 0.001) and fatigue (-2.4, P = 0.03). Multivariable analyses among adults found the number of reported symptoms was associated with worse function in all eight PROMIS measures and the number of ER visits was associated with worse fatigue, pain interference, sleep impairment, depression, anxiety and social satisfaction. Laboratory markers of disease severity (i.e. proteinuria, estimated glomerular filtration rate and serum albumin) did not predict PRO in multivariable analyses, with the single exception of complete remission and better pain interference scores among children (+9.3, P = 0.03). CONCLUSIONS: PROs provide important information about HRQoL for persons with FSGS that is not captured solely by the examination of laboratory-based markers of disease. However, it is critical that instruments capture the patient experience and FSGS clinical trials may benefit from a disease-specific instrument more sensitive to within-patient changes.

Group-Based Care in Adults and Adolescents With Hypertension and CKD: A Feasibility Study.

RATIONALE & OBJECTIVE: Group-based care provides an opportunity to increase patient access to providers without increasing physician time and is effective in the management of chronic diseases in the general population. This model of care has not been investigated in chronic kidney disease (CKD). STUDY DESIGN: Randomized controlled trial in adults (n = 50); observational study in adolescents (n = 10). SETTING & PARTICIPANTS: Adults and adolescents with CKD and hypertension in the Bronx, NY. INTERVENTION: Group-based care (monthly sessions over 6 months) versus usual care in adults. All adolescents received group-based care and were analyzed separately. OUTCOMES: Participant attendance and satisfaction with group-based care were used to evaluate intervention feasibility. The primary clinical outcome was change in mean 24-hour ambulatory blood pressure. Secondary outcomes included physical activity, medication adherence, quality of life, and sodium intake as assessed by 24-hour urinary sodium excretion and food frequency questionnaires. RESULTS: Among adults randomly assigned to group-based care, attendance was high (77% of participants attended ≥3 sessions) and most reported higher satisfaction. Mean 24-hour ambulatory systolic blood pressure decreased by -4.2 (95% CI, -13.3 to 5.8) mm Hg in group-based care patients compared with usual care at 6 months but this was not statistically significant. Similarly, we did not detect significant differences in health-related behaviors (such as medication adherence, sodium intake, and physical activity) or quality-of-life measures between the 2 groups. Among the adolescents, attendance was very poor; self-reported satisfaction, although high, did not change from baseline compared with the 6-month follow-up. LIMITATIONS: Small study size, missing data. CONCLUSIONS: Group-based care is feasible and acceptable among adults with hypertension and CKD. However, a larger trial is needed to determine the effect on blood pressure and health-related behaviors. Patient participation may limit the effectiveness of group-based care models in adolescents. FUNDING: National Institutes of Health R34 DK102174. TRIAL REGISTRATION: https://clinicaltrials.gov/show/NCT02467894.

Low Serum Bicarbonate and CKD Progression in Children.

BACKGROUND AND OBJECTIVES: Studies of adults have demonstrated an association between metabolic acidosis, as measured by low serum bicarbonate levels, and CKD progression. We evaluated this relationship in children using data from the Chronic Kidney Disease in Children study. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The relationship between serum bicarbonate and a composite end point, defined as 50% decline in eGFR or KRT, was described using parametric and semiparametric survival methods. Analyses were stratified by underlying nonglomerular and glomerular diagnoses, and adjusted for demographic characteristics, eGFR, proteinuria, anemia, phosphate, hypertension, and alkali therapy. RESULTS: Six hundred and three participants with nonglomerular disease contributed 2673 person-years of follow-up, and 255 with a glomerular diagnosis contributed 808 person-years of follow-up. At baseline, 39% (237 of 603) of participants with nonglomerular disease had a bicarbonate level of ≤22 meq/L and 36% (85 of 237) of those participants reported alkali therapy treatment. In participants with glomerular disease, 31% (79 of 255) had a bicarbonate of ≤22 meq/L, 18% (14 of 79) of those participants reported alkali therapy treatment. In adjusted longitudinal analyses, compared with participants with a bicarbonate level >22 meq/L, hazard ratios associated with a bicarbonate level of <18 meq/L and 19-22 meq/L were 1.28 [95% confidence interval (95% CI), 0.84 to 1.94] and 0.91 (95% CI, 0.65 to 1.26), respectively, in children with nonglomerular disease. In children with glomerular disease, adjusted hazard ratios associated with bicarbonate level ≤18 meq/L and bicarbonate 19-22 meq/L were 2.16 (95% CI, 1.05 to 4.44) and 1.74 (95% CI, 1.07 to 2.85), respectively. Resolution of low bicarbonate was associated with a lower risk of CKD progression compared with persistently low bicarbonate (≤22 meq/L). CONCLUSIONS: In children with glomerular disease, low bicarbonate was linked to a higher risk of CKD progression. Resolution of low bicarbonate was associated with a lower risk of CKD progression. Fewer than one half of all children with low bicarbonate reported treatment with alkali therapy. Long-term studies of alkali therapy's effect in patients with pediatric CKD are needed.

Urinary Epidermal Growth Factor as a Marker of Disease Progression in Children With Nephrotic Syndrome.

INTRODUCTION: Childhood-onset nephrotic syndrome has a variable clinical course. Improved predictive markers of long-term outcomes in children with nephrotic syndrome are needed. This study tests the association between baseline urinary epidermal growth factor (uEGF) excretion and longitudinal kidney function in children with nephrotic syndrome. METHODS: The study evaluated 191 participants younger than 18 years enrolled in the Nephrotic Syndrome Study Network, including 118 with their first clinically indicated kidney biopsy (68 minimal change disease; 50 focal segmental glomerulosclerosis) and 73 with incident nephrotic syndrome without a biopsy. uEGF was measured at baseline for all participants and normalized by the urine creatinine (Cr) concentration. Renal epidermal growth factor (EGF) mRNA was measured in the tubular compartment microdissected from kidney biopsy cores from a subset of patients. Linear mixed models were used to test if baseline uEGF/Cr and EGF mRNA expression were associated with change in estimated glomerular filtration rate (eGFR) over time. RESULTS: Higher uEGF/Cr at baseline was associated with slower eGFR decline during follow-up (median follow-up = 30 months). Halving of uEGF/Cr was associated with a decrease in eGFR slope of 2.0 ml/min per 1.73 m2 per year (P < 0.001) adjusted for age, race, diagnosis, baseline eGFR and proteinuria, and APOL1 genotype. In the biopsied subgroup, uEGF/Cr was correlated with EGF mRNA expression (r = 0.74; P < 0.001), but uEGF/Cr was retained over mRNA expression as the stronger predictor of eGFR slope after multivariable adjustment (decrease in eGFR slope of 1.7 ml/min per 1.73 m2 per year per log2 decrease in uEGF/Cr; P < 0.001). CONCLUSION: uEGF/Cr may be a useful noninvasive biomarker that can assist in predicting the long-term course of kidney function in children with incident nephrotic syndrome.

Preterm birth and neonatal acute kidney injury: implications on adolescent and adult outcomes.

As a result of preterm birth, immature kidneys are exposed to interventions in the NICU that promote survival, but are nephrotoxic. Furthermore, the duration of renal development may be truncated in these vulnerable neonates. Immaturity and nephrotoxic exposures predispose preterm newborns to acute kidney injury (AKI), particularly in the low birth weight and extremely preterm gestational age groups. Several studies have associated preterm birth as a risk factor for future chronic kidney disease (CKD). However, only a few publications have investigated the impact of neonatal AKI on CKD development. Here, we will review the evidence linking preterm birth and AKI in the NICU to CKD and highlight the knowledge gaps and opportunities for future research. For neonatal intensive care studies, we propose the inclusion of AKI as an important short-term morbidity outcome and CKD findings such as a reduced glomerular filtration rate in the assessment of long-term outcomes.

Grip strength in children with chronic kidney disease.

BACKGROUND: The relationship between muscle strength and chronic kidney disease (CKD) in children is unknown. This study aims to quantify the association between grip strength (GS) and kidney function and to explore factors associated with grip strength in children and adolescents with CKD. METHODS: We included 411 children (699 GS assessments) of the Chronic Kidney Disease in Children (CKiD) study. They were matched by age, sex, and height to a healthy control from the National Health and Nutrition Examination Survey to quantify the relationship between GS and CKD. Linear mixed models were used to identify factors associated with GS among CKD patients. RESULTS: Median GS z-score was - 0.72 (IQR - 1.39, 0.11) among CKD patients with CKD stages 2 through 5 having significantly lower GS than CKD stage 1. Compared with healthy controls, CKiD participants had a decreased GS z-score (- 0.53 SD lower, 95% CI - 0.67 to - 0.39) independent of race/ethnicity and body mass index. Factors associated with reduced GS included longer duration of CKD, pre-pubertal status, delayed puberty, neuropsychiatric comorbidities, need of feeding support, need for alkali therapy, and hemoglobin level. Decreased GS was also associated with both a lower frequency and intensity of physical activity. CONCLUSIONS: CKD is associated with impaired muscle strength in children independent of growth retardation and BMI. Exposure to CKD for a prolonged time is associated with impaired muscle strength. Potential mediators of the impact of CKD on muscle strength include growth retardation, acidosis, poor nutritional status, and low physical activity. Additional studies are needed to assess the efficacy of interventions targeted at these risk factors.

An uncommon case of arthrogryposis, renal dysfunction, and cholestasis (ARC) syndrome and review of the renal involvement: Questions.

Arthrogryposis, renal dysfunction, and cholestasis syndrome is a rare autosomal recessive disorder caused by mutations in the VPS33B and VIPAR genes. Most cases are fatal within the first year of life. Here we describe one of the two oldest patients with arthrogryposis, renal dysfunction, and cholestasis syndrome. This is a 12-year-old Hispanic female, from a non-consanguineous parents, diagnosed with an incomplete phenotype of arthrogryposis, renal dysfunction, and cholestasis syndrome with arthrogryposis and renal tubular dysfunction but without cholestasis. At 11 years of age, she was found to have impaired renal function, nephrotic-range proteinuria, Fanconi syndrome, and distal renal tubular acidosis. She also had hypercalciuria, nephrogenic diabetes insipidus, and small kidneys by renal ultrasound. Genetic analysis using whole exome sequencing showed a mutation and a partial deletion in the VPS33B gene. Further studies showed that the mother has a partial deletion in the VPS33B gene. Her medication regimen includes potassium citrate and enalapril.