The Study of the Epidemiology of Pediatric Hypertension Registry (SUPERHERO): Rationale and Methods.

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 Diagnostic Codes, 10th Revision (ICD-10 code)-defined hypertension disorder ≥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, U.S. 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 (i) reduce CVD burden across the life course and (ii) establish gold-standard biomedical informatics methods for youth with hypertension disorders.

Omentectomy reduces the need for peritoneal dialysis catheter revision in children: a study from the Pediatric Nephrology Research Consortium.

BACKGROUND: There are no multi-center studies examining omentectomy and peritoneal dialysis (PD) catheter revision in the pediatric dialysis population. METHODS: We performed a retrospective study at eight centers within the Pediatric Nephrology Research Consortium (PNRC). Data review included all incident tunneled PD catheters placed between 1/1/2011 and 12/31/2016 in pediatric stage 5 chronic kidney disease (CKD 5) patients. The primary outcome was the need for catheter revision and/or replacement. Multivariable logistic regression was performed to evaluate predictors for catheter revision/replacement. RESULTS: Data from 184 children (62.5% male; median age 7.4 years) were analyzed. Omentectomy was completed in 63.6% (n = 117). Revision/replacement occurred in 34.2% (n = 63); median time to revision/replacement was 38.5 days after insertion. PD catheter revision/replacement catheter occurred in 23.9% who underwent omentectomy versus 52.2% without omentectomy (p = 0.0005). Children ≥ 6 years at the time of catheter insertion experienced fewer revisions/replacements (18.2% age ≥ 6 vs. 56.5% age < 6 years, p <0.001). After adjusting for covariates, omentectomy reduced the need for revision by 63%; revision was 3.66 times more likely in those < 6 years of age. CONCLUSIONS: This multi-center study demonstrates that omentectomy at the time of PD catheter insertion in pediatric patients is strongly associated with reduced likelihood of PD catheter revision. Omentectomy should be considered at the time of PD catheter insertion, especially in young children who are at high risk for PD catheter malfunction. A higher resolution version of the Graphical abstract is available as Supplementary information.

HLA-DQA1 and APOL1 as Risk Loci for Childhood-Onset Steroid-Sensitive and Steroid-Resistant Nephrotic Syndrome.

BACKGROUND: Few data exist for the genetic variants underlying the risk for steroid-sensitive nephrotic syndrome (SSNS) in children. The objectives of this study were to evaluate HLA-DQA1 and APOL1 variants as risk factors for SSNS in African American children and use classic HLA antigen types and amino acid inference to refine the HLA-DQA1 association. STUDY DESIGN: Case-control study. SETTING & PARTICIPANTS: African American children with SSNS or steroid-resistant nephrotic syndrome (SRNS) were enrolled from Duke University and centers participating in the Midwest Pediatric Nephrology Consortium. FACTOR: Genetic variants in HLA-DQA1 (C34Y [rs1129740]; F41S [rs1071630]) and APOL1 high-risk alleles. OUTCOMES: SSNS and SRNS. MEASUREMENTS: Direct sequencing for the HLA-DQA1 and APOL1 variants in 115 African American children (65 with SSNS and 50 with SRNS). Imputation of classic HLA alleles and amino acids was done in 363 South Asian children. RESULTS: The 2 HLA-DQA1 variants were significantly associated with SSNS in African American children (C34Y: P=5.7 × 10-11; OR, 3.53; 95% CI, 2.33-5.42; F41S: P=1.2 × 10-13; OR, 4.08; 95% CI, 2.70-6.28), but not with SRNS (C34Y: P=0.6; F41S: P=0.2). APOL1 high-risk variants were not associated with SSNS (P=0.5) but showed significant associations with SRNS (P=1.04 × 10-7; OR, 4.17; 95% CI, 2.23-7.64). HLA-DQA1*0201, HLA-DQB1*0201, and HLA-DRB1*0701 were the classic HLA alleles with the most significant associations with SSNS risk. The most significantly associated amino acid positions were HLA-DQα1 56 and 76 (both P=2.8 × 10-7). Conditional analysis revealed that these variants most likely account for the observed association. LIMITATIONS: Modest sample size and limited statistical power to detect small to moderate effect sizes. Children studied may not be representative of all African American children in the United States. CONCLUSIONS: HLA-DQA1 is a risk locus for SSNS, but not SRNS, in African American children, consistent with its role in SSNS risk in children of European, Asian, and African ancestries. There is little evidence of a significant role for the APOL1 high-risk alleles in childhood SSNS in African American children. Refinement of the HLA-DQA1 association identified the critical classic HLA antigen types and amino acids of the HLA-DQ α1 molecule.

Kidney transplantation in children with decreased left ventricular systolic function: a Midwest Pediatric Nephrology Consortium study.

BACKGROUND: Left ventricular (LV) systolic dysfunction is a relatively uncommon but serious complication of pediatric chronic kidney disease, and may be related to uremia and uncontrolled hypertension. There is limited information on the strategy for managing these children. In some cases, combined heart-kidney transplant may be considered or kidney transplant delayed until cardiac function improves. It is unknown whether these patients are at increased risk for poor outcomes after kidney transplantation. METHODS: We conducted a retrospective, multicenter study on the outcomes of children with severe and symptomatic cardiomyopathy who underwent kidney transplantation. RESULTS: Eleven patients receiving maintenance dialysis with systolic dysfunction underwent kidney transplantation without simultaneous heart transplant. Nine patients had congestive heart failure in the pre-transplant period. There were no identified complications post-transplant related to the underlying cardiac dysfunction. LV systolic function normalized in all patients and the mean shortening fraction increased from 19.0 ± 4.6 % to 32.0 ± 4.4 % (p < 0.0001). CONCLUSIONS: Kidney transplantation should be considered for children receiving maintenance dialysis with severe LV dysfunction.

Improving data quality in observational research studies: Report of the Cure Glomerulonephropathy (CureGN) network.

BACKGROUND: High data quality is of crucial importance to the integrity of research projects. In the conduct of multi-center observational cohort studies with increasing types and quantities of data, maintaining data quality is challenging, with few published guidelines. METHODS: The Cure Glomerulonephropathy (CureGN) Network has established numerous quality control procedures to manage the 70 participating sites in the United States, Canada, and Europe. This effort is supported and guided by the activities of several committees, including Data Quality, Recruitment and Retention, and Central Review, that work in tandem with the Data Coordinating Center to monitor the study. We have implemented coordinator training and feedback channels, data queries of questionable or missing data, and developed performance metrics for recruitment, retention, visit completion, data entry, recording of patient-reported outcomes, collection, shipping and accessing of biological samples and pathology materials, and processing, cataloging and accessing genetic data and materials. RESULTS: We describe the development of data queries and site Report Cards, and their use in monitoring and encouraging excellence in site performance. We demonstrate improvements in data quality and completeness over 4 years after implementing these activities. We describe quality initiatives addressing specific challenges in collecting and cataloging whole slide images and other kidney pathology data, and novel methods of data quality assessment. CONCLUSIONS: This paper reports the CureGN experience in optimizing data quality and underscores the importance of general and study-specific data quality initiatives to maintain excellence in the research measures of a multi-center observational study.

The Improving Renal Outcomes Collaborative: Blood Pressure Measurement in Transplant Recipients.

BACKGROUND AND OBJECTIVES: Hypertension is highly prevalent in pediatric kidney transplant recipients and contributes to cardiovascular death and graft loss. Improper blood pressure (BP) measurement limits the ability to control hypertension in this population. Here, we report multicenter efforts from the Improving Renal Outcomes Collaborative (IROC) to standardize and improve appropriate BP measurement in transplant patients. METHODS: Seventeen centers participated in structured quality improvement activities facilitated by IROC, including formal training in quality improvement methods. The primary outcome measure was the proportion of transplant clinic visits with appropriate BP measurement according to published guidelines. Prospective data were analyzed over a 12-week pre-intervention period and a 20-week active intervention period for each center and then aggregated as of the program-specific start date. We used control charts to quantify improvements across IROC centers. We applied thematic analysis to identify patterns and common themes of successful interventions. RESULTS: We analyzed data from 5392 clinic visits. At baseline, BP was measured and documented appropriately at 11% of visits. Center-specific interventions for improving BP measurement included educating clinic staff, assigning specific team member roles, and creating BP tracking tools and alerts. Appropriate BP measurement improved throughout the 20-week active intervention period to 78% of visits. CONCLUSIONS: We standardized appropriate BP measurement across 17 pediatric transplant centers using the infrastructure of the IROC learning health system and substantially improved the rate of appropriate measurement over 20 weeks. Accurate BP assessment will allow further interventions to reduce complications of hypertension in pediatric kidney transplant recipients.

Adrenocorticotropic Hormone for Childhood Nephrotic Syndrome: The ATLANTIS Randomized Trial.

BACKGROUND AND OBJECTIVES: There is renewed interest in adrenocorticotropic hormone (ACTH) for the treatment of nephrotic syndrome. We evaluated the efficacy and safety of ACTH in children with frequently relapsing or steroid-dependent nephrotic syndrome in a randomized trial. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Participants aged 2-20 years old with frequently relapsing or steroid-dependent nephrotic syndrome were enrolled from 16 sites in the United States and randomized 1:1 to ACTH (repository corticotropin injection) or no relapse-preventing treatment. ACTH treatment regimen was 80 U/1.73 m2 administered twice weekly for 6 months, followed by 40 U/1.73 m2 administered twice weekly for 6 months. The primary outcome was disease relapse during the first 6 months. Participants in the control group were offered crossover to ACTH treatment if they relapsed within 6 months. Secondary outcomes were relapse after ACTH dose reduction and treatment side effects. RESULTS: The trial was stopped at a preplanned interim analysis after enrollment of 31 participants because of a lack of discernible treatment efficacy. Fourteen out of 15 (93%) participants in the ACTH arm experienced disease relapse in the first 6 months, with a median time to first relapse of 23 days (interquartile range, 9-32), compared with 15 out of 16 (94%) participants and at a median of 21 days (interquartile range, 14-51) in the control group. There was no difference in the proportion of relapsed patients (odds ratio, 0.93; 95% confidence interval, 0.05 to 16.40; P>0.99) or time to first relapse (hazard ratio, 1.03; 95% confidence interval, 0.50 to 2.15; P=0.93). Thirteen out of 16 participants in the control group crossed over to ACTH treatment. Three out of 28 participants completed 12 months of ACTH treatment; the others exited the trial because of frequent relapses or side effects. There were no disease relapses after ACTH dose reduction among the three participants. Most side effects were mild and similar to side effects of corticosteroids. CONCLUSIONS: ACTH at 80 U/1.73 m2 administered twice weekly was ineffective at preventing disease relapses in pediatric nephrotic syndrome.