Use of the Kidney Failure Risk Equation to Determine the Risk of Progression to End-stage Renal Disease in Children With Chronic Kidney Disease

IMPORTANCE

The kidney failure risk equation (KFRE) has been shown to accurately estimate progression to kidney failure in adults with chronic kidney disease (CKD). Use of the KFRE in children with CKD, if accurate, would help to optimize planning for end-stage renal disease (ESRD) care.

OBJECTIVE

To determine whether the KFRE adequately discriminates the risk of ESRD in children with CKD.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included 603 children with an estimated glomerular filtration rate of less than 60 mL/min/1.73 m2 in the Chronic Kidney Disease in Children study, a national multicenter observational study. Data were collected from January 1, 2005, through July 31, 2013, and analyzed from September 30, 2016, through September 8, 2017.

EXPOSURES

The primary predictive factors were the 4-variable (age, sex, bedside Schwartz estimated glomerular filtration rate, and ratio of albumin to creatinine levels) and 8-variable (4 variables plus serum calcium, phosphate, bicarbonate, and albumin levels) KFREs, which provide 1-, 2-, and 5-year estimates of the risk of progression to ESRD.

MAIN OUTCOMES AND MEASURES

Time to ESRD. The Cox proportional hazards model was used to examine the association between the KFRE score and time to ESRD. C statistics were used to discriminate ESRD risk by the KFRE, with a value of greater than 0.80 indicating strong discrimination.

RESULTS

Of the 603 children included in the study, 378 were boys (62.7%) and 225 were girls (37.3%); median age at study entry was 12 years (interquartile range, 8-15 years). Median estimated glomerular filtration rate was 44 mL/min/1.73 m2. Four hundred fifty-seven participants (75.8%) had a nonglomerular cause of CKD. Median observation time was 3.8 years (interquartile range, 1.7-6.2 years); 144 (23.9%) developed ESRD within 5 years of enrollment. The 4-variable KFRE scores discriminated risk of ESRD, with C statistics of 0.90, 0.86, and 0.81 for the 1-, 2-, and 5-year risk scores, respectively. Results were similar using the 8-variable equation.

CONCLUSIONS AND RELEVANCE

The KFRE is a simple tool that provides excellent discrimination of the risk of ESRD. Results suggest that the KFRE could be incorporated into the clinical care of children with CKD to aid in anticipatory guidance, timing of referral for transplant evaluation, and planning for dialysis access.

Effect of Immigration Status on Outcomes in Pediatric Kidney Transplant Recipients

Kidney transplantation is the optimal treatment for children with end-stage renal disease. For children with undocumented immigration status, access to kidney transplantation is limited, and data on transplant outcomes in this population are scarce. The goal of the present retrospective single-center study was to compare outcomes after kidney transplantation in undocumented children with those of US citizen children. Undocumented residency status was identified in 48 (17%) of 289 children who received a kidney transplant between 1998 and 2010. In undocumented recipients, graft survival at 1 and 5 years posttransplantation was similar, and mean estimated glomerular filtration rate at 1 year was higher than that in recipients who were citizens. The risk of allograft failure was lower in undocumented recipients relative to that in citizens at 5 years posttransplantation, after adjustment for patient age, donor age, donor type, and HLA mismatch (p < 0.04). In contrast, nearly one in five undocumented recipients who reached 21 years of age lost their graft, primarily because they were unable to pay for immunosuppressive medications once their state-funded insurance had ended. These findings support the ongoing need for immigration policies for the undocumented that facilitate access to work-permits and employment-related insurance for this disadvantaged group.

Comparable Survival of En Bloc versus Standard Donor Kidney Transplants in Children

OBJECTIVE

To determine whether renal transplantation survival is similar in children receiving pediatric en bloc kidneys compared with those receiving standard deceased donor kidneys.

STUDY DESIGN

We compared time to allograft failure and estimated glomerular filtration rate (eGFR) in pediatric recipients of en bloc and standard criteria deceased donor renal transplants using Organ Procurement and Transplantation Network data for 2000-2013. Cox regression analysis was used to compare time to allograft failure, and the Student t test was used to compare eGFR.

RESULTS

A total of 6882 recipients met the study inclusion criteria; 1.8% received an en bloc transplant. The adjusted hazard for allograft failure was similar for recipients of en bloc kidneys compared with standard criteria kidneys (hazard ratio, 1.15; 95% CI, 0.83-1.59; P = .41). The median wait time for transplantation was significantly shorter for recipients of en bloc kidneys (157 days vs 208 days; P = .03). Moreover, eGFR was superior for recipients of en bloc kidneys up to 5 years post-transplantation.

CONCLUSION

Transplantation of en bloc pediatric kidneys should be considered a viable option for pediatric recipients and may afford unique benefits by reducing wait times and promoting preservation of graft function.

Effect of BMI on allograft function and survival in pediatric renal transplant recipients

OBJECTIVE

To determine whether pre-transplant body mass index (BMI) affects renal allograft function and survival in pediatric renal transplant recipients.

STUDY DESIGN

This is a retrospective cohort study using the Organ Procurement and Transplantation Network data from 2000 to 2013 to compare time to total allograft loss (allograft failure or death), prevalence of delayed graft function, prevalence of acute rejection, and estimated glomerular filtration rate (eGFR) post-transplant in pediatric renal transplant recipients categorized by BMI z-score.

RESULTS

A total of 8804 kidney transplant recipients met our inclusion criteria, and of those, 6% were underweight, 14% were overweight, and 17% were obese pre-transplant. The adjusted hazard ratio (HR) for allograft failure was significantly higher for obese recipients compared to normal weight recipients (HR 1.25, 95% CI 1.1, 1.42); for every 1 point increase in BMI z-score, there was a 7% increased hazard of allograft failure (HR 1.07; 95% CI 1.03-1.1, p < 0.001). The prevalence of delayed graft function and acute rejection increased with higher BMI z-score category; however, this difference did not reach statistical significance. eGFR at 1 and 5 years post-transplant decreased with higher BMI z-score although it was only statistically significant at 1 year.

CONCLUSIONS

Obesity is prevalent in pediatric renal transplant recipients, and obese, but not overweight or underweight, pediatric renal transplant recipients have an increased risk of allograft failure. Implementation of effective obesity interventions in pediatric renal transplant recipients is of critical importance to improve longevity of the renal allograft.

Higher eGFR at Dialysis Initiation Is Not Associated with a Survival Benefit in Children

BACKGROUND

Study findings suggest that initiating dialysis at a higher eGFR level in adults with ESRD does not improve survival. It is less clear whether starting dialysis at a higher eGFR is associated with a survival benefit in children with CKD.

METHODS

To investigate this issue, we performed a retrospective cohort study of pediatric patients aged 1-18 years who, according to the US Renal Data System, started dialysis between 1995 and 2015. The primary predictor was eGFR at the time of dialysis initiation, categorized as higher (eGFR>10 ml/min per 1.73 m²) versus lower eGFR (eGFR≤10 ml/min per 1.73 m²).

RESULTS

Of 15,170 children, 4327 (29%) had a higher eGFR (median eGFR, 12.8 ml/min per 1.73 m²) at dialysis initiation. Compared with children with a lower eGFR (median eGFR, 6.5 ml/min per 1.73 m²), those with a higher eGFR at dialysis initiation were more often white, girls, underweight or obese, and more likely to have GN as the cause of ESRD. The risk of death was 1.36 times higher (95% confidence interval, 1.24 to 1.50) among children with a higher (versus lower) eGFR at dialysis initiation. The association between timing of dialysis and survival differed by treatment modality-hemodialysis versus peritoneal dialysis (P<0.001 for interaction)-and was stronger among children initially treated with hemodialysis (hazard ratio, 1.56, 95% confidence interval, 1.39 to 1.75; versus hazard ratio, 1.07, 95% confidence interval, 0.91 to 1.25; respectively).

CONCLUSIONS

In children with ESRD, a higher eGFR at dialysis initiation is associated with lower survival, particularly among children whose initial treatment modality is hemodialysis.

Eculizumab exposure in children and young adults: indications, practice patterns, and outcomes-a Pediatric Nephrology Research Consortium study

BACKGROUND

Eculizumab is approved for the treatment of atypical hemolytic uremic syndrome (aHUS). Its use off-label is frequently reported. The aim of this study was to describe the broader use and outcomes of a cohort of pediatric patients exposed to eculizumab.

METHODS

A retrospective, cohort analysis was performed on the clinical and biomarker characteristics of eculizumab-exposed patients < 25 years of age seen across 21 centers of the Pediatric Nephrology Research Consortium. Patients were included if they received at least one dose of eculizumab between 2008 and 2015. Traditional summary statistics were applied to demographic and clinical data.

RESULTS

A total of 152 patients were identified, mean age 9.1 (+/-6.8) years. Eculizumab was used "off-label" in 44% of cases. The most common diagnoses were aHUS (47.4%), Shiga toxin-producing Escherichia coli HUS (12%), unspecified thrombotic microangiopathies (9%), and glomerulonephritis (9%). Genetic testing was available for 60% of patients; 20% had gene variants. Dosing regimens were variable. Kidney outcomes tended to vary according to diagnosis. Infectious adverse events were the most common adverse event (33.5%). No cases of meningitis were reported. Nine patients died of noninfectious causes while on therapy.

CONCLUSIONS

This multi-center retrospective cohort analysis indicates that a significant number of children and young adults are being exposed to C5 blockade for off-label indications. Dosing schedules were highly variable, limiting outcome conclusions. Attributable adverse events appeared to be low. Cohort mortality (6.6%) was not insignificant. Prospective studies in homogenous disease cohorts are needed to support the role of C5 blockade in kidney outcomes.

Gross hematuria as a sign of acute rejection

In the contemporary era of potent immunosuppressive regimens, previously encountered signs of renal allograft rejection such as fever and hematuria are rarely encountered. We report a teenager with severe recurrent acute humoral and cellular rejection whose presenting feature was gross hematuria with the presence of blood clots in the urine. We want to highlight that severe rejection even in the setting of modern immunosuppressive drugs can present as gross hematuria. Contrary to conventional wisdom that gross hematuria with the presence of blood clots in the urine is indicative of pathology in the renal collecting system, a parenchymal disease process should also be considered in renal transplant recipients.

Long-term impact of immigration status on outcomes in pediatric kidney transplant recipients

This study aimed to investigate the effects of documentation status on pediatric kidney transplant outcomes in a single-center setting, emphasizing the significance of state insurance access for undocumented patients and federal policies like Deferred Action for Childhood Arrivals (DACA) on patient outcomes. A cohort of 283 patients, including 48 undocumented individuals, who received their first kidney transplant as children between 1998 and 2011 was analyzed. There was no significant difference in unadjusted all-cause (P = .91) and death-censored (P = .38) graft survival between undocumented patients and patients with permanent legal status, subsequently referred to as US residents. Additionally, in the Cox proportional hazards model, immigration status was not significantly associated with all-cause graft survival (hazard ratio 0.87, 95% CI 0.51-1.46, P = .6). Telephone interviews were conducted with the undocumented cohort. Forty-one of 48 of the undocumented recipients were contacted. Ninety-five percent had access to insurance with 68.3% on Medicaid or Medicare. DACA recipients exhibited higher employment rates (88% vs 67%, P = .11) and were more likely to complete a degree beyond high school (47.1% vs 12.5%, P = .01). Immigration status did not impact long-term graft survival, suggesting eligibility expansions for state-funded insurance and DACA may improve access to transplant care for undocumented patients. Moreover, DACA recipients showed trends toward increased employment and education compared to non-DACA recipients.

Trends in Timing of Preemptive Kidney Transplantation and Association with Allograft and Survival Outcomes in Children

Key Points

Preemptive kidney transplant is occurring at higher levels of eGFR in US children over time. Higher level of eGFR at the time of transplant is not associated with patient or allograft survival. Implications of the observed trend of performing preemptive kidney transplant at higher eGFR on the long-term health of children deserve further study.

Background

There has been a recent trend toward starting dialysis at higher eGFRs in children, with no identified survival benefits. We aimed to determine whether there are similar trends in the timing of preemptive kidney transplant and whether higher eGFR (≥15 ml/min per 1.73 m2) at preemptive kidney transplant was associated with clinical outcomes among US children.

Methods

We performed a retrospective cohort study of 1514 children in the United States Renal Data System who received a preemptive kidney transplant between 2006 and 2019. In primary analysis, we examined the association between calendar year and eGFR (ml/min per 1.73 m2) at the time of preemptive kidney transplant, categorized as higher (eGFR ≥15) versus lower (eGFR <15) using logistic regressions. The relationship between eGFR at preemptive kidney transplant and graft failure or death was assessed using Cox proportional hazards and Fine–Gray models.

Results

We found a temporal trend in eGFR at preemptive kidney transplant in children; every 5-year increase in calendar period was associated with 55% higher odds (95% confidence interval, 1.35 to 1.79) of receiving a preemptive kidney transplant at higher eGFR. There was no association between preemptive kidney transplant at higher (versus lower) eGFR and risk of allograft failure or death (hazard ratio, 1.12; 95% confidence interval, 0.87 to 1.43) over a median follow-up of 5.7 years.

Conclusions

There has been a trend toward preemptive kidney transplant at higher eGFR over time in children. Receipt of a preemptive kidney transplant at higher eGFR was not associated with allograft or patient survival. Implications of these trends deserve further study.

Inactivated Measles Virus Vaccine

Formaldehyde-inactivated, alum-adsorbed measles virus vaccine is not stable at 22°C for longer than 3 weeks. The vaccine is stable, however, for 16 months at 5°C and stimulates an antigenic response in guinea pigs equal to that of freshly prepared vaccines.