Differences in medication adherence by sex and organ type among adolescent and young adult solid organ transplant recipients.

BACKGROUND: Identification of differences in medication adherence by sex or organ type may help in planning interventions to optimize outcomes. We compared immunosuppressive medication adherence between males and females, and between kidney, liver and heart transplant recipients. METHODS: This multicenter study of prevalent kidney, liver and heart transplant recipients 14-25 years assessed adherence 3 times (0, 3, 6 months post-enrollment) with the BAASIS self-report tool. At each visit, participants were classified as adherent if they missed no doses in the prior 4 weeks and non-adherent otherwise. Adherence was also assessed using the coefficient of variation (CV) of tacrolimus trough levels; CV < 30% was classified as adherent. We used multivariable mixed effects logistic regression models adjusted for potential confounders to compare adherence by sex and by organ. RESULTS: Across all visits, males (n = 150, median age 20.4 years, IQR 17.2-23.3) had lower odds of self-reported adherence than females (n = 120, median age 19.8 years, IQR 17.1-22.7) (OR 0.41, 95% CI 0.21-0.80) but higher odds of adherence by tacrolimus CV (OR 2.50, 95% CI 1.30-4.82). No significant differences in adherence (by self-report or tacrolimus CV) were noted between the 184 kidney, 58 liver, and 28 heart recipients. CONCLUSION: Females show better self-reported adherence than males but greater variability in tacrolimus levels. Social desirability bias, more common in females than males, may contribute to better self-reported adherence among females. Higher tacrolimus variability among females may reflect biologic differences in tacrolimus metabolism between males and females rather than sex differences in adherence. There were no significant differences in adherence by organ type.

Transition of young adult kidney transplant recipients.

Survival of pediatric kidney transplant recipients has improved over the past six decades. However, adolescents and young adults still have the highest graft failure rates of any age group. There is a growing need for well-designed transition programs to ensure the successful integration of young adults into adult society with eventual transfer of care and management in adult transplant centers. In this review, we discuss the risk factors contributing to the high risk of kidney graft failure observed between 17 and 24 years of age, including the role of transfer from pediatric to adult care. We also address the unique challenges of adolescents with kidney transplant: the impact of chronic kidney disease on neurocognition, age-related changes in immune activity, and suboptimal adherence during the transition process. We then describe strategies to mitigate these risks by designing developmentally appropriate transition programs, and review the evidence supporting the benefits of well-designed multidisciplinary transition programs.

Development of a patient-reported outcome measure for the assessment of symptom burden in pediatric chronic kidney disease (PRO-Kid).

BACKGROUND: Chronic kidney disease (CKD) and kidney failure in childhood are associated with significant and life-altering morbidities and lower quality of life. Emerging evidence suggests that management should be guided in part by symptom burden; however, there is currently no standardized assessment tool for quantifying symptom burden in this pediatric population. This study aimed to develop and refine a patient-reported symptom assessment tool for children with CKD/kidney failure (PRO-Kid), to evaluate the frequency and impact of symptoms. METHODS: This was a prospective observational study of children and caregivers of children with CKD/kidney failure at two Canadian pediatric care centers. Building on previously published patient-reported outcome measures (PROs) for the assessment of symptom burden in other populations, we drafted a 13-item questionnaire. Cognitive interviews were performed with children and caregivers of children with CKD/kidney failure to iteratively refine the questionnaire. RESULTS: Twenty-four participants completed cognitive interviewing (11 children, 13 caregivers). The most common symptoms endorsed were feeling left out, feeling sad/depressed, inability to focus, tiredness, nausea, vomiting, not wanting to eat, and changes in the taste of food. Feeling left out was added to the questionnaire as almost all participants voiced this as a frequent and impactful symptom, resulting in a 14-item questionnaire. CONCLUSIONS: PRO-Kid is the first pediatric CKD/kidney failure-specific PRO tool to assess symptom burden. Future work should validate this tool in a larger cohort so that it may be used to improve the care of children living with CKD/kidney failure. A higher resolution version of the Graphical abstract is available as Supplementary information.

Care processes and structures associated with higher medication adherence in adolescent and young adult transplant recipients.

BACKGROUND: We aimed to identify care processes and structures that were independently associated with higher medication adherence among young transplant recipients. METHODS: We conducted a prospective, observational cohort study of 270 prevalent kidney, liver, and heart transplant recipients 14-25 years old. Patients were ≥3 months post-transplant, ≥2 months post-discharge, and followed in one of 14 pediatric or 14 adult transplant programs in Canada. Patients were enrolled between June 2015 and March 2018 and followed for 6 months. Adherence was assessed at baseline, 3, and 6 months using the BAASIS© self-report tool. Patients were classified as adherent if no doses were missed in the prior 4 weeks. Transplant program directors and nurses completed questionnaires regarding care organization and processes. RESULTS: Of the 270 participants, 99 were followed in pediatric programs and 171 in adult programs. Median age was 20.3 years, and median time since transplant was 5 years. At baseline, 71.5% were adherent. Multivariable mixed effects logistic regression models with program as a random effect identified two program-level factors as independently associated with better adherence: minimum number of prescribed blood draws per year for those >3 years post-transplant (per 1 additional) (OR 1.12 [95% CI 1.00, 1.26]; p = .047), and average time nurses spend with patients in clinic (per 5 additional minutes) (OR 1.15 [1.03, 1.29]; p = .017). CONCLUSION: Program-level factors including protocols with a greater frequency of routine blood testing and more nurse time with patients were associated with better medication adherence. This suggests that interventions at the program level may support better adherence.

Kidney disease in children with heart or liver transplant.

Over the past few decades, there has been increasing recognition of kidney disease in children with non-kidney solid organ transplantation. The risk of kidney disease in children undergoing heart or liver transplantation is higher than the general population as the underlying disease and its associated management may directly impair kidney function. Both heart and liver failures contribute to hypoperfusion and kidney ischemia before patients reach the point of transplant. The transplant surgery itself can often be complicated by acute kidney injury (AKI), which may be further exacerbated by a complicated postoperative course. In the short- and long-term post-transplant period, these children are at risk of acute illness, exposed to nephrotoxic medications, and susceptible to rare but severe infections and immunologic insults that may contribute to AKI and chronic kidney disease (CKD). In some, CKD can progress to kidney failure with replacement therapy (KFRT). CKD and KFRT are associated with increased morbidity and mortality in this patient population. Therefore, it is critical to monitor for and recognize the risk factors for kidney injury in this population and mitigate these risks. In this paper, the authors provide an overview of kidney disease pertaining to heart and liver transplantation in children with guidance on monitoring, diagnosis, prevention, and management.

Developing Consensus-Based Outcome Domains for Trials in Children and Adolescents With CKD: An International Delphi Survey.

RATIONALE & OBJECTIVE: The inconsistency in outcomes reported and lack of patient-reported outcomes across trials in children with chronic kidney disease (CKD) limits shared decision making. As part of the Standardized Outcomes in Nephrology (SONG)-Kids initiative, we aimed to generate a consensus-based prioritized list of critically important outcomes to be reported in all trials in children with CKD. STUDY DESIGN: An online 2-round Delphi survey in English, French, and Hindi languages. SETTINGS & PARTICIPANTS: Patients (aged 8-21 years), caregivers/family, and health care professionals (HCPs) rated the importance of outcomes using a 9-point Likert scale (7-9 indicating critical importance) and completed a Best-Worst Scale. ANALYTICAL APPROACH: We assessed the absolute and relative importance of outcomes. Comments were analyzed thematically. RESULTS: 557 participants (72 [13%] patients, 132 [24%] caregivers, and 353 [63%] HCPs) from 48 countries completed round 1 and 312 (56%) participants (28 [40%] patients, 64 [46%] caregivers, and 220 [56%] HCPs) completed round 2. Five outcomes were common in the top 10 for each group: mortality, kidney function, life participation, blood pressure, and infection. Caregivers and HCPs rated cardiovascular disease higher than patients. Patients gave lower ratings to all outcomes compared with caregivers/HCPs except they rated life participation (round 2 mean difference, 0.1), academic performance (0.1), mobility (0.4), and ability to travel (0.4) higher than caregivers and rated ability to travel (0.4) higher than HCPs. We identified 3 themes: alleviating disease and treatment burden, focusing on the whole child, and resolving fluctuating and conflicting goals. LIMITATIONS: Most participants completed the survey in English. CONCLUSIONS: Mortality, life participation, kidney function, and blood pressure were consistently highly prioritized by patients, caregivers, and HCPs. Patients gave higher priority to some lifestyle-related outcomes compared with caregivers/HCPs. Establishing critically important outcomes for all trials in children with CKD may improve consistent reporting of survival, kidney health, and clinical and life impact outcomes that are meaningful for decision making.

Brain abnormalities in children and adolescents with chronic kidney disease.

BACKGROUND: Chronic kidney disease (CKD) is a risk factor for vascular disease and stroke. The spectrum of brain injury and microstructural white matter abnormalities in children with CKD is largely unknown. METHODS: Cross sectional study at two North American pediatric hospitals. A cohort of 49 children, 29 with CKD, including renal transplant (mean age 14.4 ± 2.9 years; range 9-18), and 20 healthy controls (mean age 13.7 ± 3.1 years; range 9-18) had their conventional brain magnetic resonance images (MRIs) reviewed by one neuroradiologist to determine the prevalence of brain injury. Fractional anisotropy (FA) maps calculated from diffusion tensor imaging (DTI) were generated to compare white matter microstructure in CKD compared to controls, using tract-based spatial statistics (TBSS). RESULTS: Focal and multifocal white matter injury was seen on brain MRI in 6 children with CKD (21%). Relative to controls, CKD subjects showed reduced white matter fractional anisotropy and increased mean diffusivity and radial diffusivity in the anterior limb of the internal capsule, suggestive of abnormal myelination. CONCLUSION: Cerebral white matter abnormalities, including white matter injury, are under-recognized in pediatric CKD patients. Brain imaging studies through progression of CKD are needed to determine the timing of white matter injury and any potentially modifiable risk factors.

Vitamin D insufficiency and deficiency in pediatric renal transplant recipients.

Vitamin D deficiency is prevalent in the pediatric CKD population. Recognizing that renal transplant recipients have CKD, we assessed the prevalence of vitamin D insufficiency and deficiency in pediatric renal transplant recipients, compared to a healthy pediatric population. We prospectively studied 25(OH)D levels in 29 pediatric renal transplant recipients and 45 control patients over one yr. The overall prevalence of vitamin D insufficiency and deficiency was common in both populations, at 76% (95% CI: 61, 87%) in the pediatric renal transplant recipients and 91% (95% CI: 80, 98%) in the control group. In the paired renal transplant samples, the mean 25(OH)D level was 52.3 ± 17.9 nmol/L in the winter and 65.6 ± 18.8 nmol/L in the summer (95% CI diff.: 3.9, 22.7), in keeping with a significant seasonal difference. The mean dietary intake of vitamin D in the renal transplant recipients, assessed by three-day dietary record, was 5.7 µg/day, with a vitamin D intake below the EAR in the majority. We did not find an association between vitamin D intake and 25(OH)D levels in this study, likely due to the low dietary intake of vitamin D within the transplant population, identifying a potential area for intervention and improvement.

Validation of Patient-Reported Outcome measure in pediatric chronic Kidney disease (PRO-Kid).

BACKGROUND: Measuring the burden of symptoms that matter most to children and adolescents with chronic kidney disease (CKD) is essential for optimizing patient-centered care. We developed a novel CKD-specific Patient-Reported Outcome measure (PRO-Kid) to assess both frequency and impact of symptoms in children. In the current study, we further assessed the validity and internal consistency of PRO-Kid. METHODS: In this multicenter study, children age 8 to 18 years with stages 3-5 CKD, including those on dialysis, were recruited from five pediatric centers. Children completed the 14-item PRO-Kid questionnaire and the validated Pediatric Quality of Life Inventory (PedsQL™ 4.0). We explored the dimensionality of the PRO-kid scale using exploratory and confirmatory factor analysis, to either establish that it is a unidimensional construct or identify evidence of subfactors. We then assessed internal consistency (Cronbach's alpha [Cα]) and construct validity (Pearson correlations). RESULTS: In total, 100 children were included. The median eGFR was 27.4 ml/min/1.73m2 [7.43, 63.4], and 26 children (26%) were on dialysis. Both the PRO-Kid frequency and the impact scales were unidimensional. Cα was high for both the PRO-Kid frequency and impact scales, 0.83 (95% CI = 0.78 to 0.88) and 0.84 (95% CI = 0.80 to 0.89) respectively, showing strong internal consistency. Pearson correlations between PRO-Kid and PedsQL™ scores were also strong: -0.78 (95% confidence interval [CI] = -0.85 to -0.70) for the frequency score and -0.69 (95% CI = -0.78 to -0.56) for the impact score, reflecting the association between poorer quality of life and higher symptom burden. CONCLUSIONS: PRO-Kid is a novel patient-reported symptom burden tool for children 8-18 years of age with CKD that correlates strongly in the expected direction with PedsQL™, supporting its validity. Future work will evaluate changes in PRO-Kid score with progression of CKD, and implementation of the tool into clinical care.

Access to and Health Outcomes of Pediatric Solid Organ Transplantation for Indigenous Children in 4 Settler-colonial Countries: A Scoping Review.

Solid organ transplantation (SOT) is considered the optimal treatment for children with end-stage organ failure; however, increased efforts are needed to understand the gap surrounding equitable access to and health outcomes of SOT for Indigenous children. This scoping review summarizes the literature on the characteristics of access to and health outcomes of pediatric SOT among Indigenous children in the settler-colonial states of Canada, Aotearoa New Zealand, Australia, and the United States. A search was performed on MEDLINE, EMBASE, PsycINFO, and CINAHL for studies matching preestablished eligibility criteria from inception to November 2021. A preliminary gray literature search was also conducted. Twenty-four studies published between 1996 and 2021 were included. Studies addressed Indigenous pediatric populations within the United States (n = 7), Canada (n = 6), Aotearoa New Zealand (n = 5), Australia (n = 5), and Aotearoa New Zealand and Australia combined (n = 1). Findings showed that Indigenous children experienced longer time on dialysis, lower rates of preemptive and living donor kidney transplantation, and disparities in patient and graft outcomes after kidney transplantation. There were mixed findings about access to liver transplantation for Indigenous children and comparable findings for graft and patient outcomes after liver transplantation. Social determinants of health, such as geographic remoteness, lack of living donors, and traditional spiritual beliefs, may affect SOT access and outcomes for Indigenous children. Evidence gaps emphasize the need for action-based initiatives within SOT that prioritize research with and for Indigenous pediatric populations. Future research should include community-engaged methodologies, situated within local community contexts, to inform culturally safe care for Indigenous children.

Utility and cost of a renal transplant transition clinic.

Successful transition from paediatric-centred to adult-oriented healthcare positively influences health outcomes for youth with chronic illness. The primary objective is to evaluate outcomes pre- and post provision of multidisciplinary transition clinic (TC) care to renal transplant recipients. We compared patient and allograft survival in renal transplant recipients at British Columbia Children's Hospital who received care within a transition clinic (TC) to a cohort of patients transferred prior to establishment of the TC, pre-TC (PTC) in 2007. Baseline characteristics, allograft function, and survival data were collected prospectively via a validated provincial database for 2 years posttransfer. We also estimated and compared the average yearly per-patient cost during the 2-year follow-up period. Thirty-three patients were transferred (PTC) and 12 transitioned (TC). In the PTC cohort, there was a combined poor outcome (death or allograft loss) incidence of 24% within 2 years posttransfer compared with no death or allograft loss in the TC cohort. Cost estimates indicate the average yearly per-patient cost was Canadian dollars (CAD) $17,127-$38,909 for the PTC and CAD $11,380-$34,312 for the TC cohort. For PTC patients who lost their allograft and returned to dialysis, the per-patient cost was CAD $40,956-$61,470. Our results indicate improved allograft and patient survival posttransfer of care in renal transplant recipients who attended TCs, and we found that providing TCs is economically feasible.

Prevalence of sleep disturbances in children and adolescents with chronic kidney disease.

Although sleep disorders are common in adults with chronic kidney disease, little is known about the prevalence of sleep problems in children and adolescents with chronic kidney disease and their relationship to health-related quality of life measurements. We performed a clinic-based survey of sleep habits and common symptoms of sleep disturbances in 159 school-aged patients with chronic kidney disease. Three patient groups of chronic kidney disease were assessed: group 1, those not on dialysis and not transplanted; group 2, those on dialysis; and group 3, those with a functioning renal allograft. Four symptom domains for sleep disorders were assessed: excessive daytime sleepiness; sleep disordered breathing; restless legs syndrome symptoms; and insufficient sleep. Patients and the parent-proxy also completed the Pediatric Quality of Life Inventory Version 4.0 Generic Core Scales questionnaire. Ninety-three (93) patients (58.5%) had symptoms of a sleep disturbance. The presence of a sleep disturbance correlated with a decrease in health-related quality of life scores that was independent of the chronic kidney disease study group or estimated glomerular filtration rate. We conclude that sleep disturbances are common throughout the spectrum of chronic kidney disease in children and adolescents and are associated with diminished health-related quality of life scores.

Pregnancy outcomes among solid organ transplant recipients in British Columbia.

OBJECTIVE: Since 1954, over 14 000 women have given birth after having had an organ transplantation. Unfortunately, some women and physicians remain misinformed about the feasibility and outcomes of pregnancy post transplantation. Our primary objective was to assess their perceptions and difficulties with regard to becoming pregnant. Our secondary objectives were to determine the incidence of pregnancies among transplant recipients in British Columbia and any maternal, graft, or fetal complications. METHODS: From 1997 to 2007 in British Columbia, there were over 500 female recipients of solid organ transplants. We surveyed recipients in this group who were of child-bearing age. RESULTS: One hundred forty of 295 (47%) eligible recipients responded: 44 of these women had attempted pregnancy after transplant, and 31 women gave birth to 47 children. One half of the respondents planned to have children post transplant; 108 of 140 (77%) had no children before transplant. One quarter of the respondents were advised against pregnancy by their physician, and 33% of these women found a new physician to support their pregnancy. Rates of miscarriage (27%), rejection (21%), and prematurity (65%) were higher than expected. Infections were rare, and no birth defects or noteworthy health problems in the offspring were reported. CONCLUSIONS: Overall, pregnancy appears to be safe following solid organ transplantation, but careful monitoring and counselling are recommended.

A Guide for Adult Nephrologists and Hematologists to Managing Atypical Hemolytic Uremic Syndrome and C3 Glomerulopathy in Teens Transitioning to Young Adults.

Atypical hemolytic uremic syndrome and C3 glomerulopathy/immune complex membranoproliferative glomerulonephritis are ultra-rare chronic, complement-mediated diseases with childhood manifestation in a majority of cases. Transition of clinical care of patients from pediatric to adult nephrologists-typically with controlled disease in native or transplant kidneys in case of atypical hemolytic uremic syndrome and often with chronic progressive disease despite treatment efforts in case of C3 glomerulopathy/immune complex membranoproliferative glomerulonephritis-identifies a challenging juncture in the journey of these patients. Raising awareness for the vulnerability of this patient cohort; providing education on disease pathophysiology and management including the use of new, high-precision complement antagonists; and establishing an ongoing dialog of patients, families, and all members of the health care team involved on either side of the age divide will be inevitable to ensure optimal patient outcomes and a safe transition of these patients to adulthood.

Functional Magnetic Resonance Imaging Findings in Children and Adolescents With Chronic Kidney Disease: Preliminary Findings.

This cross-sectional study provides preliminary findings from one of the first functional brain imaging studies in children with chronic kidney disease (CKD). The sample included 21 children with CKD (ages, 14.4 ± 3.0 y) and 11 healthy controls (ages, 14.5 ± 3.4 y). Using functional magnetic resonance imaging during a visual-spatial working memory task, findings showed that the CKD group and healthy controls invoked similar brain regions for encoding and retrieval phases of the task, but significant group differences were noted in the activation patterns for both components of the task. For the encoding phase, the CKD group showed lower activation in the posterior cingulate, anterior cingulate, precuneus, and middle occipital gyrus than the control group, but more activation in the superior temporal gyrus, middle frontal gyrus, middle temporal gyrus, and the insula. For the retrieval phase, the CKD group showed underactivation for brain systems involving the posterior cingulate, medial frontal gyrus, occipital lobe, and middle temporal gyrus, and greater activation than the healthy controls in the postcentral gyrus. Few group differences were noted with respect to disease severity. These preliminary findings support evidence showing a neurologic basis to the cognitive difficulties evident in pediatric CKD, and lay the foundation for future studies to explore the neural underpinnings for neurocognitive (dys)function in this population.

Reducing Unnecessary Imaging in Children With Multicystic Dysplastic Kidney or Solitary Kidney.

BACKGROUND AND OBJECTIVES: Children with isolated unilateral multicystic dysplastic kidney (MCDK) or congenital solitary kidney (CSK) undergo serial renal ultrasonography with variable frequency until they are transitioned to adult care. A growing body of literature suggests the value of frequent ultrasonography in this population is limited, providing no benefit to overall outcomes. Despite emerging evidence, ultrasound remains overused, resulting in avoidable health care expenditures and unnecessary use of resources. With our initiative, we aimed to improve quality of care by reducing avoidable ultrasounds in these children. METHODS: This was a single-center, prospective, interrupted time series of children <18 years with ultrasound-confirmed isolated unilateral MCDK or CSK in the outpatient nephrology clinic to evaluate the effect of a decision-making algorithm on the proportion of children receiving an avoidable ultrasound. An algorithm depicting a consensus, evidence-based protocol for managing pediatric MCDK or CSK was refined through content expert feedback and usability testing to standardize frequency of ultrasonography. Ultrasounds were deemed necessary after birth, at 6 months, and at 2, 5, 10, and 15 years. Differences pre- and postintervention were determined by using a U chart and t and F tests for significance. RESULTS: The algorithm resulted in a 47% reduction (P < .001) in the proportion of avoidable ultrasounds ordered in children with MCDK and CSK. This reduction was sustainable over a 6-month period and would result in at least $46 000 annual savings. CONCLUSIONS: Introduction of a clinical decision-making algorithm was associated with a reduction in avoidable ultrasound testing. Improving adherence across providers may allow for an even more pronounced reduction.

Cost Effectiveness and Impact in Quality of Care of a Pediatric Multidisciplinary Stone Clinic.

Herein, we assess the cost-effectiveness of a multidisciplinary clinic for children with urinary stones. The clinic's primary goals were to decrease unnecessary visits, imaging, and costs while optimizing the quality of care. METHODS: Between October 2012 and January 2016, children with complex stone disease, previously treated in urology and/or nephrology clinics, were seen at a triannual pediatric combined stone clinic. We compared the number and cost of ultrasounds, emergency room (ER) visits, and stone surgeries performed before and after each patient's initial evaluation. All patients received satisfaction surveys. RESULTS: Among the 79 patients, 27 were seen at least twice in the combined clinic and followed multiple times in either urology or nephrology clinics. The mean number of ER visits per patient per year significantly decreased from 0.29 ± 0.36 to 0.10 ± 0.15 (P = 0.002). The mean cost of ER visits went from CAD$ 23.44 ± 28.80 to CAD$ 4.14 ± 12.18 (P = 0.002). Likewise, the mean annual number and cost of stone-related surgeries significantly decreased [(0.38 ± 0.63 versus 0.20 ± 0.32 after the MSC started (P = 0.026) and mean annual cost of surgeries went from CAD$ 182.97 ± 301.49 to CAD$ 41.59 ± 110.97 (P = 0.022)]. Among the survey responses returned, 75% of families believed the clinic was time-saving. CONCLUSIONS: Despite a small sample size, the number of ER visits and stone-related operations significantly decreased after the initial combined clinic intervention. Longer-term data will hopefully confirm if the positive findings continue.

Association Between Chronic Kidney Disease-Mineral Bone Disease (CKD-MBD) and Cognition in Children: Chronic Kidney Disease in Children (CKiD) Study.

RATIONALE & OBJECTIVE: Chronic 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 DESIGN: Observational study. PARTICIPANTS: 702 children enrolled in the Chronic Kidney Disease in Children (CKiD) Study. PREDICTORS: Plasma 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). OUTCOMES: Neurocognitive tests of intelligence, academic achievement, and executive functions. ANALYTICAL APPROACH: Linear 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. RESULTS: At 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 < 0.05); specifically, Conners' Continuous Performance Test II Errors of Omission (ß = 2.3 [1.0, 3.6]), Variability (ß=1.4 [0.4, -2.4]), and Hit Reaction Time (ß = 1.3 [0.2, 2.4]). Children in the highest FGF-23 tertile group had 7% and 9% greater cognitive risk for Hit Reaction Time and Errors of Omission compared with those in the lowest tertile, respectively. In fully adjusted analyses, higher FGF-23 tertile was associated with increased cognitive risk (P < 0.05) for Errors of Omission (ß = 0.4 [0.1, 0.7]) and Hit Reaction Time (ß = 0.4 [0.1, 0.7]). LIMITATIONS: The study does not assess the cumulative effects of FGF-23 excess on cognitive function over time. Within-population stratified analyses were not performed due to limited sample size. CONCLUSIONS: In children with CKD, higher plasma FGF-23 level is associated with lower performance in targeted tests of executive function, specifically attention regulation, independent of glomerular filtration rate.

Association of Time-Varying Blood Pressure With Chronic Kidney Disease Progression in Children.

Importance: Optimal blood pressure (BP) management in children with chronic kidney disease (CKD) slows progression to end-stage renal disease. Studies often base progression risk on a single baseline BP measurement, which may underestimate risk. Objective: To determine whether time-varying BP measurements are associated with a higher risk of progression of CKD than baseline BP measurements. Design, Setting, and Participants: The ongoing longitudinal, prospective cohort study Chronic Kidney Disease in Children (CKID) recruited children from January 19, 2005, through March 19, 2014, from pediatric nephrology centers across North America, with data collected at annual study visits. Participants included children aged 1 to 16 years with a diagnosis of CKD and a glomerular filtration rate (GFR) of 30 to 90 mL/min/1.73 m2. Data were analyzed from February 11, 2005, through February 13, 2018. Exposures: Office BP measurement classified as less than 50th percentile, 50th to less than 90th percentile, or at least 90th percentile. Blood pressure categories were treated as time fixed (baseline) or time varying (updated at each visit) in models. Main Outcomes and Measures: A composite renal outcome (50% GFR reduction from baseline, estimated GFR less than 15 mL/min/1.73 m2, or dialysis or transplant). Pooled logistic models using inverse probability weighting estimated the hazard odds ratio (HOR) of the composite outcome associated with each BP category stratified by CKD diagnosis. Results: A total of 844 children (524 [62.1%] male; median age, 11 [interquartile range, 8-15] years; 151 [17.9%] black; 580 [68.7%] with nonglomerular CKD; and 264 [31.3%] with glomerular CKD) with complete baseline data and median follow-up of 4 (interquartile range, 2-6) years were included. One hundred ninety-six participants with nonglomerular diagnoses (33.8%) and 99 with glomerular diagnoses (37.5%) reached the composite outcome. Baseline systolic BP in at least the 90th percentile was associated with a higher risk of the composite outcome (HOR for nonglomerular disease, 1.58 [95% CI, 1.07-2.32]; HOR for glomerular disease, 2.85 [95% CI, 1.64-4.94]) compared with baseline systolic BP in less than the 50th percentile. Time-fixed estimates were substantially lower compared with time-varying systolic BP percentile categories (HOR among those with nonglomerular CKD, 3.75 [95% CI, 2.53-5.57]; HOR among those with glomerular diagnoses, 5.96 [95% CI, 3.37-10.54]) comparing those at or above the 90th percentile vs below the 50th percentile. Adjusted models (adjusted for proteinuria and use of antihypertensives) attenuated the risk in nonglomerular CKD (adjusted HOR for baseline measurement, 1.52 [95% CI, 0.98-2.36]; adjusted HOR for time-varying measurement, 2.25 [95% CI, 1.36-3.72]) and in glomerular CKD (adjusted HOR for baseline, 0.97 [95% CI, 0.39-2.36]; adjusted HOR for time-varying measurement, 1.41 [95% CI, 0.65-3.03]). Similar results were observed for diastolic BP. Conclusions and Relevance: Among children with nonglomerular CKD included in this study, elevated time-varying BP measurements were associated with a greater risk of CKD progression compared with baseline BP measurement. This finding suggests that previous studies using only baseline BP likely underestimated the association between BP and CKD progression.

Outcome of kidney transplantation in Canadian Aboriginal children in the province of British Columbia.

Renal transplantation remains the therapy of choice for children and adolescents with ESRD. Differences in graft survival are observed in kidney transplant recipients of different race and ethnicities. Data in pediatric populations are limited and confounded by disparities in access to health care. We performed a retrospective single Canadian centre database review to determine the short- and long-term outcomes of kidney transplantation in Aboriginal children compared to non-Aboriginals. A total of 159 primary renal transplant recipients at BCCH between 1985 and 2005 were examined (15% Aboriginal). Aboriginal children had different etiologies of ESRD, and a higher percentage of females, but were similar in age at transplantation, cold ischemia time and living donation rate. Early graft outcomes such as delayed graft function, episodes of acute rejection in the first year post-transplant and estimated glomerular function rate at one yr were similar in both groups. Long-term graft survival, however, was significantly worse in the Aboriginal group, with a significantly increased rate of late rejections: 50% compared with 26.7% among non-Aboriginals (p = 0.03). In a province with uniform access to health care, significant differences in long-term graft outcome exist among Aboriginal children compared with non-Aboriginals.