<p><strong>BACKGROUND: </strong>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.</p>

<p><strong>METHODS: </strong>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.</p>

<p><strong>RESULTS: </strong>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.</p>

<p><strong>CONCLUSIONS: </strong>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.</p>

<p>Kidney transplantation is the preferred treatment for pediatric end-stage renal disease (ESRD). Preemptive transplantation avoids the increased morbidity and mortality of dialysis. Yet, previous studies have not demonstrated significant graft or patient survival benefits for children undergoing transplantation preemptively versus nonpreemptively. These previous studies were limited by small samples sizes and low rates of adverse events. Here we compared graft failure and mortality rates using Kaplan-Meier methods and Cox regression among a large national cohort of children with ESRD undergoing preemptive versus nonpreemptive kidney transplantation between 2000 and 2012. Among 7527 pediatric kidney transplant recipients in the United States Renal Data System, 1668 underwent preemptive transplantation. Over a median 4.8 years follow-up, 1314 experienced graft failure, and over a median 5.2 years of follow-up, 334 died. Dialysis exposure versus preemptive transplantation conferred a higher risk of graft failure (hazard ratio 1.32; 95% confidence interval: 1.10-1.56) and a higher risk of death (hazard ratio 1.69; 95% confidence interval: 1.22-2.33) in multivariable analysis. Compared with children undergoing preemptive transplantation, children on dialysis for &gt;1 year had a 52% higher risk of graft failure and those on dialysis &gt;18 months had an 89% higher risk of death, regardless of donor source. Thus, preemptive transplantation is associated with substantial benefits in allograft and patient survival among children with ESRD, particularly when compared with children who receive dialysis for &gt;1 year. These findings support policies to promote early access to transplantation and avoidance of dialysis for children with ESRD whenever feasible.</p>

<p>This study was undertaken to describe the association of patient race/ethnicity and renal allograft survival among the national cohort of pediatric renal allograft recipients. Additionally, we determined whether racial and ethnic differences in graft survival exist among individuals living in low- or high-poverty neighborhoods and those with private or public insurance. Among 6216 incident, pediatric end-stage renal disease patients in the United States Renal Data System (kidney transplant from 2000 through September, 2011), 14.4% experienced graft failure, with a median follow-up time of 4.5 years. After controlling for multiple covariates, black race, but not Hispanic ethnicity, was significantly associated with a higher rate of graft failure for both deceased and living donor transplant recipients. Disparities were particularly stark by 5 years post transplant, when black living donor transplant recipients experienced only 63.0% graft survival compared with 82.8 and 80.8% for Hispanics and whites, respectively. These disparities persisted among high- and low-poverty neighborhoods and among both privately and publicly insured patients. Notably profound declines in both deceased and living donor graft survival rates for black, compared with white and Hispanic, children preceded the 3-year mark when transplant Medicare eligibility ends. Further research is needed to identify the unique barriers to long-term graft success among black pediatric transplant recipients.</p>