Hemoglobin decline in children with chronic kidney disease: baseline results from the chronic kidney disease in children prospective cohort study

BACKGROUND AND OBJECTIVES

The level of glomerular filtration rate at which hemoglobin declines in chronic kidney disease is poorly described in the pediatric population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This cross-sectional study of North American children with chronic kidney disease examined the association of glomerular filtration rate, determined by the plasma disappearance of iohexol, and hemoglobin concentration.

RESULTS

Of the 340 patients studied, the mean age was 11 +/- 4 yr, the mean glomerular filtration rate was 42 +/- 14 ml/min per 1.73 m(2), and the mean hemoglobin was 12.5 +/- 1.5. Below a glomerular filtration rate of 43, the hemoglobin declined by 0.3 g/dl (95% confidence interval -0.2 to -0.5) for every 5-ml/min per 1.73 m(2) decrease in glomerular filtration rate. Above a glomerular filtration rate of 43 ml/min per 1.73 m(2), the hemoglobin showed a nonsignificant decline of 0.1 g/dl for every 5-ml/min per 1.73 m(2) decrease in glomerular filtration rate.

CONCLUSIONS

In pediatric patients with chronic kidney disease, hemoglobin declines as an iohexol-determined glomerular filtration rate decreases below 43 ml/min per 1.73 m(2). Because serum creatinine-based estimated glomerular filtration rates may overestimate measured glomerular filtration rate in this population, clinicians need to be mindful of the potential for hemoglobin decline and anemia even at early stages of chronic kidney disease, as determined by current Schwartz formula estimates. Future longitudinal analyses will further characterize the relationship between glomerular filtration rate and hemoglobin, including elucidation of reasons for the heterogeneity of this association among individuals.

Reduced albumin levels and utilization of arteriovenous access in pediatric patients with systemic lupus erythematosus (SLE)

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects between five and ten thousand children in the USA. Kidney disease may progress to end-stage renal disease (ESRD) and subsequent need for dialysis therapy in a significant number of children with SLE. We performed a cross-sectional analysis comparing achievement of National Kidney Foundation/Kidney Disease Outcomes Quality Initiative clinical targets in pediatric patients with SLE maintained on hemodialysis (HD) to pediatric patients with other causes of ESRD. Ninety-seven unique SLE patients and two control groups-1,823 unique pediatric patients with other causes of ESRD and 694 pediatric patients with glomerulonephritis-were identified in the End Stage Renal Disease Clinical Performance Measures 2000-2004 Project Years. SLE patients were older, with a female and black race predominance compared with both control groups. Pediatric patients maintained on HD secondary to SLE were less likely to meet albumin targets and more likely to have vascular catheters than were pediatric patients on HD secondary to other causes. These findings may be associated with increased morbidity and mortality in pediatric patients with SLE maintained on HD and deserve further study.

Glomerular filtration rate measurement and estimation in chronic kidney disease

Glomerular filtration rate (GFR) assesses kidney function. GFR is measured by renal clearance techniques; inulin clearance is the gold standard but is not easily measured. Thus, other methods to determine GFR have been utilized. Endogenous creatinine clearance (CrCl) is the most widely used, but creatinine secretion falsely elevates GFR. Cimetidine inhibits creatinine secretion, such that CrCl equals GFR, provided there are no difficulties with bladder emptying. Estimation of GFR from serum creatinine (e.g. Schwartz formula) is useful clinically; however, such formulae have not been updated for enzymatic creatinine autoanalyzers. Cystatin C, a small protein, is produced at a relatively constant rate and is reabsorbed in the proximal tubule. Cystatin C may be more sensitive than creatinine in detecting a reduction in GFR, but further studies are needed to prove this. Single injection (plasma) clearance techniques are the most precise measures of GFR. Iohexol is an exogenous marker that is comparable to inulin and (51)Cr-EDTA and can be measured by high-performance liquid chromatography (HPLC). Our pilot and the Chronic Kidney Disease in Children (CKiD) North American studies show that iohexol can accurately measure GFR using a four-point plasma disappearance curve national studies show that iohexol can accurately measure GFR using a four-point plasma disappearance curve (10, 30, 120, and 300 min) or, in most cases, a two-point disappearance time (120 and 300 min).

An Assessment of Health Related Quality of Life Using the Child Health and Illness Profile-Adolescent Edition in Adolescents With Chronic Kidney Disease Due to Underlying Urological Disorders

PURPOSE

We examined health related quality of life in adolescents with congenital urological disease causing kidney disease using a generic health related quality of life instrument. We then compared the results to those in adolescents with medical kidney disease and to population based norms.

MATERIALS AND METHODS

The Child Health and Illness Profile-Adolescent Edition was administered to 113 patients 10 to 18 years old with chronic kidney disease. Mean domain and subdomain scores for adolescents with urological disease were compared to those of adolescents with medical kidney disease and to population based norms.

RESULTS

The cohort included adolescents with an underlying diagnosis of congenital urological anomaly (37 patients) or other causes of kidney disease (76). Compared to adolescents with kidney disease caused by other factors, those with congenital urological disease scored statistically significantly better in the Child Health and Illness Profile-Adolescent Edition subdomain of Limitations of Activity (mean 22.3 [SD 2.5] vs 20.4 [SD 5.0], p = 0.04). Compared to population norms, adolescents with congenital disorders scored lower in the Disorders domain (mean 16.5, 95% CI 14.2 to 18.9) but better in the Risks domain (mean 25.9, 95% CI 25.1 to 26.6) and in the Home Safety and Health subdomain (mean 25.2, 95% CI 23.7 to 26.6).

CONCLUSIONS

As assessed by the Child Health and Illness Profile-Adolescent Edition generic health status questionnaire, adolescents with kidney disease due to underlying congenital urological disease had fewer limitations of activity compared to those with underlying medical kidney disease. Except for low scores in the Disorders domain, children with underlying urological disease did not have significant impairments in any other domain compared to population based norms.

Birth weight, postnatal growth, and risk for high blood pressure at 7 years of age: results from the Collaborative Perinatal Project

OBJECTIVE

A physiologic predisposition toward hypertension is theorized to result from the combination of intrauterine growth restriction followed by rapid catch-up growth. The objective of this study was to evaluate the effects of birth weight and weight gain during childhood on the risk for high blood pressure in childhood and to identify discrete periods of catch-up growth that put children with intrauterine growth restriction at increased risk for the development of high blood pressure later in life.

METHODS

The US Collaborative Perinatal Project (1959-1974) studied 55,908 pregnancies in an observational cohort at 12 medical centers in the United States and followed the offspring through 7 years of age. All white or black children who were born at term and completed the follow-up without kidney or heart disease were included in this posthoc analysis. z scores were calculated for weight at birth, 4 months, 1 year, 4 years, and 7 years on the basis of study means and SD. Changes in z scores were calculated for each interval.

RESULTS

Each 1-kg increase in birth weight increased the odds for high systolic blood pressure by 2.19 and high diastolic blood pressure by 1.82 when race and change in weight z scores were also included in the regression model. An increase in weight z score of 1 SD above the previous weight z score increased the odds for high systolic blood pressure at 7 years by 1.65 (birth to 4 months), 1.79 (4 months to 1 year), 1.71 (1-4 years), and 1.94 (4-7 years) in the full model. White race increased the odds for high systolic blood pressure by 1.51.

CONCLUSIONS

In this large biracial US cohort, infants who were small for gestational age were not at increased risk for high blood pressure at 7 years of age. However, children who crossed weight percentiles upward during early childhood did demonstrate an increased risk.

Kidney stones and the ketogenic diet: risk factors and prevention

A cohort study was performed of children started on the ketogenic diet for intractable epilepsy from 2000 to 2005 (n = 195). Children who developed kidney stones were compared with those without in terms of demographics, urine laboratory markers, and intervention with urine alkalinization (potassium citrate). Thirteen children (6.7%) developed kidney stones. The use of oral potassium citrate significantly decreased the prevalence of stones (3.2% vs 10.0%, P = .049) and increased the mean time on the ketogenic diet before a stone was first noted (260 vs 149 patient-months, P = .29). The prevalence of kidney stones did not correlate with younger age or use of carbonic anhydrate inhibitors (eg, topiramate or zonisamide) but trended toward higher correlation with the presence of hypercalciuria (92% vs 71%, P = .08). No child stopped the diet due to stones; in fact, the total diet duration was longer (median 26 vs 12 months, P < .001). Kidney stones continue to occur in approximately 1 in 20 children on the ketogenic diet, and no statistically significant risk factors were identified in this cohort. As oral potassium citrate was preventative, prospective studies using this medication empirically are warranted.

The association of anemia and hypoalbuminemia with accelerated decline in GFR among adolescents with chronic kidney disease

We sought to describe rates of kidney function decline and to identify modifiable risk factors for CKD progression in a multicenter prospective cohort study of adolescents with CKD aged 11 to 18 years seen semiannually for up to three years. Of the 23 subjects meeting inclusion criteria, the average estimated GFR was 51 +/- 27 ml/min/1.73 m(2) (0.85 +/- 0.45 ml/s/1.73 m(2)) at entry. The overall annualized decline in GFR was 5.6 ml/min/1.73 m(2) (0.093 ml/s/1.73 m(2)) per year (95% confidence interval [95% CI]: 1.9 to 9.3 [0.032 to 0.16]). The adjusted annualized decline in GFR was found to be accelerated in males, as well as among those over 15 years of age. The adjusted annualized decline in GFR was greater among those with either anemia (hematocrit below 36%), or hypoalbuminemia (albumin below 4 g/dl [40 g/L]). After adjustment, anemia was associated with an accelerated decline of 7.8 ml/min/1.73 m(2) (0.13 ml/s/1.73 m(2)) (95% CI: 3.3 to 12 [0.055 to 0.20]) and hypoalbuminemia was associated with an accelerated decline of 17 ml/min/1.73 m(2) (0.28 ml/s/1.73 m(2)) (95% CI: 11 to 22 [0.18 to 0.37]). Further study is needed to evaluate whether treatment of anemia or hypoalbuminemia, as outlined in current clinical care guidelines for CKD, may slow the progression of CKD in adolescents.

Racial Disparities in the Association between Birth Weight in the Term Infant and Blood Pressure at Age 7 Years: Results from the Collaborative Perinatal Project

BP has been inversely associated with birth weight in studies worldwide, but few studies have included black individuals. The US National Collaborative Perinatal Project followed 58,960 pregnant women and their resultant offspring for 7 yr. In this post hoc analysis, all term white or black children without kidney or heart disease were included (n = 29,710). The effect of birth weight and other risk factors on systolic (SBP) and diastolic BP (DBP) was evaluated at 7 yr. Mean birth weight and body mass index at 7 yr were slightly lower for black compared with white children (birth weight 3.14 +/- 0.48 versus 3.32 +/- 0.46 kg [P < 0.001]; body mass index 15.8 +/- 2.0 versus 16.3 +/- 2.0 [P < 0.001]). Compared with white mothers, black mothers were less likely to smoke (41 versus 52%), were more anemic (23 versus 7%), and were more likely to live in poverty (72 versus 39%). In linear regression, there was significant interaction between race and birth weight in predicting SBP (P = 0.002). In bivariate analysis, birth weight was positively associated with SBP (beta = 0.87) and DBP (beta = 1.14) in black children (P < 0.001) but not associated with either in white children. With maternal poverty, educational level, and anemia during pregnancy added to the model, birth weight remained a significant positive predictor of SBP (beta = 0.89, P < 0.001) in black but not in white children (beta = 0.02, P = 0.17). The association between birth weight and SBP differs between black and white children. The cause of intrauterine growth restriction-associated hypertension seems to be race sensitive; therefore, future studies of racial disparities in the "Barker hypothesis" may help in the understanding of the mechanism of fetal programming of hypertension.

Clinical Course Associated with Vascular Access Type in a National Cohort of Adolescents Who Receive Hemodialysis: Findings from the Clinical Performance Measures and US Renal Data System Projects

Limited research has described clinical outcomes that are associated with the type of vascular access in pediatric patients who receive maintenance hemodialysis. This retrospective cohort study examined prevalent pediatric patients who were aged 12 to <18 yr and identified in the 2000 ESRD Clinical Performance Measures Project as receiving in-center hemodialysis. Vascular access type as of December 31, 1999, was identified. These patients were linked with 1 yr of data (January 1, 2000, through December 31, 2000) from US Renal Data System standard analytic files that allow for the comparison of rates of hospitalizations and access complications by access type. Of the 418 patients who met inclusion criteria, the mean age was 15.6 yr, 53% were male, 49% were white, the mean time on dialysis was 22 mo, and 42% had a structural/urologic cause of ESRD; 42% of patients had an arteriovenous graft or fistula, and 58% had a vascular catheter. Patients with a vascular catheter as compared with those with a graft or fistula had the following adjusted relative risks (95% confidence interval): 1.84 (1.38 to 2.44) for hospitalization for any cause, 4.74 (2.02 to 11.14) for hospitalization as a result of infection, and 2.72 (2.00 to 3.69) for a complication of vascular access. Vascular catheters are the predominant access type in adolescent patients who receive maintenance hemodialysis and are associated with significantly more hospitalizations and complications.

Design and methods of the Chronic Kidney Disease in Children (CKiD) prospective cohort study

An estimated 650,000 Americans will have ESRD by 2010. Young adults with kidney failure often develop progressive chronic kidney disease (CKD) in childhood and adolescence. The Chronic Kidney Disease in Children (CKiD) prospective cohort study of 540 children aged 1 to 16 yr and have estimated GFR between 30 and 75 ml/min per 1.73 m2 was established to identify novel risk factors for CKD progression; the impact of kidney function decline on growth, cognition, and behavior; and the evolution of cardiovascular disease risk factors. Annually, a physical examination documenting height, weight, Tanner stage, and standardized BP is conducted, and cognitive function, quality of life, nutritional, and behavioral questionnaires are completed by the parent or the child. Samples of serum, plasma, urine, hair, and fingernail clippings are stored in biosamples and genetics repositories. GFR is measured annually for 2 yr, then every other year using iohexol, HPLC creatinine, and cystatin C. Using age, gender, and serial measurements of Tanner stage, height, and creatinine, compared with iohexol GFR, a formula to estimate GFR that will improve on traditional pediatric GFR estimating equations when applied longitudinally is expected to be developed. Every other year, echocardiography and ambulatory BP monitoring will assess risk for cardiovascular disease. The primary outcome is the rate of decline of GFR. The CKiD study will be the largest North American multicenter study of pediatric CKD.

The association between intrauterine growth restriction in the full-term infant and high blood pressure at age 7 years: results from the Collaborative Perinatal Project

OBJECTIVE

To use neonatal and placental anthropometry as proxy measures of intrauterine growth restriction (IUGR) and to relate these to blood pressure later in childhood.

STUDY DESIGN

A post hoc analysis of full-term white and black children from the Collaborative Perinatal Project, followed from birth until age 7 years (n = 29,710). Blood pressure above the 90th percentile by gender and race was considered high blood pressure. Anthropometric measures at birth included birth weight, ponderal index (PI, birth weight/birth length(3)), head to chest circumference (HCC) ratio, and placental ratio percentage (PRP, placental weight(*)100/birth weight).

RESULTS

Among anthropometric measures, PI, HCC, and birth weight were not associated with high systolic blood pressure at age 7 years, but PRP was. In multiple logistic regression, high systolic blood pressure and widened pulse pressure were both predicted by increased PRP [odds ratio (OR) 1.03 and 1.04, P < 0.001] but not by birth weight, when adjusted for gender, race, and maternal education. High diastolic blood pressure was weakly predicted by birth weight (OR 1.10, P = 0.05) but not by PRP.

CONCLUSIONS

PRP is associated with an increased risk for high systolic blood pressure and pulse pressure later in childhood, whereas birth weight, PI, and HCC are not. The proportion of placental weight to birth weight is a useful marker of IUGR for studying the developmental origins of adult disease hypothesis.

Changes in physical and psychosocial functioning among adolescents with chronic kidney disease

Little research has been published assessing changes in the functional health status of children and adolescents with chronic kidney disease (CKD). We know little about which clinical parameters influence functional status or health-related quality of life in these young people. In a prospective study using data from semi-annual visits over a 4-year period from 78 adolescents with CKD aged 11 years to 18 years, we detail the impact of several clinical measures (i.e., kidney function, albumin, hematocrit, height) on short-term changes in health-related quality of life. The 50-item Child Health Questionnaire Parent Form, a validated health-related quality of life measure in children, was used to obtain physical and psychosocial functioning summary scores at each visit. After adjustment for the variables mentioned above, the physical summary score on the Child Health Questionnaire (CHQ) declined as glomerular filtration rate declined. Increasing height was associated with a positive change in physical and psychosocial summary scores. We conclude that decline in kidney function is associated with a subsequent decline in health-related quality of life, particularly in terms of physical activity.

Neurocognitive outcomes in children with chronic kidney disease: Current findings and contemporary endeavors

Given the rise in chronic kidney disease (CKD) in both children and adults, CKD has recently been targeted as a public health priority. Childhood onset kidney disease is generally a noncurable and progressive condition that leads to kidney failure by early adulthood. Fortunately, improved identification of kidney problems allows for early intervention, which is thought to slow progression toward end-stage renal disease. In addition, medical interventions for pediatric end-stage renal disease have also improved, allowing children to take advantage of lifesaving renal replacement treatments such as dialysis and kidney transplantation. In spite of improvements in identification and treatment, CKD causes both direct and indirect insults to a variety of organ systems. This paper reviews recently published studies pertaining to the neurocognitive and psychosocial impact of CKD on children of various ages and at various stages of kidney failure. Specific attention is focused on summarizing peer reviewed research that describes associations between kidney functioning and cognitive functioning, language acquisition, visual spatial abilities, memory, and executive functioning. In addition, peer reviewed research describing psychosocial outcomes associated with CKD related to academic achievement, social-behavioral functioning, and quality of life are summarized. The authors also identified disease-specific factors that likely mediate neurocognitive outcomes (e.g., anemia, hypertension, cardiovascular) and endorse the importance of continued interdisciplinary research collaborations that will provide a better understanding of the mechanisms responsible for improved neurocognitive functioning after transplantation. The authors conclude this review by describing a multicenter, prospective, longitudinal, National Institutes of Health funded study that is currently examining the developmental outcomes of children with mild to moderate CKD. The authors speculate that the Chronic Kidney Disease in Children Prospective Cohort Study (CKiD) findings will provide additional evidence-based guidance for clinicians and researchers working with children and adolescents with deteriorating kidney function to improve medical and developmental outcomes.

Growth and nutrition in children with chronic kidney disease

Growth failure remains an important problem for children with kidney disease secondary to medical kidney disease or urologic disorders. In children with chronic kidney disease, growth remains suboptimal even with energy intake above 80% of the recommend daily allowance. Adults who had chronic kidney disease as children frequently report dissatisfaction with final adult height. Additionally, growth failure in children with end-stage renal disease is associated with adverse clinical outcomes, including more frequent hospitalizations and increased mortality. This review describes the prevalence and morbidity associated with growth retardation in US children with chronic kidney disease. Additionally, available strategies to optimize growth and nutrition and current controversies in nutritional management and assessment of nutritional status in children with chronic kidney disease are discussed.

Clinical research in pediatric nephrology: state of the art

The goals of clinical research include comparing new and standard treatments, establishing treatment efficacy, defining risk factors for disease, elucidating pathophysiologic mechanisms of disease, and establishing causation. Although the randomized clinical trial has been the "gold standard" in clinical research and is the strongest study design to establish causation for many clinical research questions, an interventional study or "experiment" such as a randomized trial is often not possible. Observational study designs also demonstrate associations between exposures and outcome. To determine whether these associations are likely to be causal, one can assess a number of qualities, first outlined by the British epidemiologist Sir Austin Bradford Hill. These qualities include analogy to what is known; the plausibility, strength and specificity of the association; consistency and coherence across studies; the temporality of the putative cause and effect; and the presence of a biological gradient. The presence of these factors adds weight to the probability that a given association is causal. Systematic reviews and meta-analyses use these factors in combining studies to assess whether associations are cause and effect. Additionally, new methods in the analysis of longitudinal data collected in observational studies can help to determine causation. In this review, we will use recent literature and contemporary topics in pediatric nephrology to illustrate state-of-the-art research methods using classic epidemiological elements needed to establish causation.

Assessing Health Status and Health Care Utilization in Adolescents with Chronic Kidney Disease

Few validated health status measures have been assessed in children with chronic kidney disease (CKD). The objective was to assess the validity of a generic health status measure, the Child Health and Illness Profile-Adolescent Edition (CHIP-AE), in adolescents with CKD. A case-control study was performed (1) to assess scores on the CHIP-AE in adolescents with CKD compared with two control groups of age-, socioeconomic-, and gender-matched peers and (2) to compare health of patients who had chronic renal insufficiency (CRI), were on dialysis, and were posttransplantation. Seven pediatric nephrology centers recruited 113 patients (mean age, 14 yr; 39 CRI, 21 dialysis, 53 posttransplantation). Compared with 226 control subjects, patients with CKD had lower overall satisfaction with health and more restriction in activity. Positively, patients with CKD had more family involvement, better home safety and health practices, and better social problem-solving skills and were less likely to participate in risky social behaviors or socialize with peers who engaged in risky behavior. Patients who received dialysis were less physically active and experienced more physical discomfort and limitations in activities than did transplant or CRI patients. It is concluded that patients with CKD have poorer functional health status than age-matched peers. Among CKD patients, dialysis patients have the poorest functional health status. These results suggest that the CHIP-AE can be used to measure functional health status in adolescent patients with CKD.

Assessing associations between medication adherence and potentially modifiable psychosocial variables in pediatric kidney transplant recipients and their families

Post-transplant immunosuppressant (IS) medication adherence is essential for long-term graft survival and relatively little is known about psychosocial barriers that interfere with optimum medication adherence in pediatric kidney transplant patients. The objective of this prospective observational cohort study was to assess the impact of modifiable psychosocial variables on medication adherence. Our hypothesis was that parental stress, dysfunctional parent-child interactions and child behavior problems would be associated with poorer medication adherence. Thirteen pediatric kidney transplant patients and their caregivers were enrolled. Transplant recipients who were able to read and caregivers of all the transplant recipients completed behavioral and attitudinal surveys. A subgroup of seven families dispensed their primary IS medication from an electronic monitoring vial (MEMS Smart Cap). For these patients, medication adherence was calculated by computing a ratio of the medication taken divided by the prescribed dose. In addition, for the entire group, serial IS levels were reviewed by two board certified pediatric nephrologists who categorized all 13 transplant recipient families as either 'probably adherent (PA)' or 'possibly non-adherent (PNA)'. Pearson correlation coefficients and independent samples Student t-tests were used to assess the association between medication adherence and psychosocial variables measured by standardized questionnaires. In this study, elevated parental stress, dysfunctional parent-child interactions, and child behavior problems were associated with poorer medication adherence. In addition, we found evidence to support the relationship between subjective dissatisfaction with appearance and poorer medication adherence. These findings suggest that pre-transplant recipient evaluations of risk factors for poor adherence are warranted.

Anemia in pediatric dialysis patients in end-stage renal disease network 5

To identify demographic and clinical characteristics associated with failure to achieve hemoglobin levels >/=11 g/dl in prevalent pediatric end-stage renal disease (ESRD) patients, a cross-sectional analysis of patient clinical data collected by the Mid-Atlantic Renal Coalition in conjunction with the 2000 and 2001 ESRD Clinical Performance Measures Projects was performed. Ninety-nine patients (mean age 12.6 years, SD 5.4) contributed 119 observations to this analysis. Of patients on hemodialysis, 36.6% were anemic, and 39.5% of patients on peritoneal dialysis (PD) were anemic. Associations between age, race, gender, assigned cause of ESRD, Kt/V, transferrin saturation, time on dialysis, serum albumin, dialysis modality, and the achievement of target hemoglobin were examined. In multivariate logistic regression analyses examining age, dialysis modality, time on dialysis, and serum albumin, each 1-year increase in age was significantly associated with hemoglobin levels <11 g/dl [adjusted odds ratio (OR) 1.18, 95% confidence interval (CI) 1.06-1.32] and PD patients were more than twice as likely to have hemoglobin levels <11 g/dl (adjusted OR 2.62, 95% CI 0.98-7.04). Patients on dialysis for 6 months or more were less likely to be anemic than those on dialysis for less than 6 months (adjusted OR 0.39, 95% CI 0.16-0.99). In conclusion, increasing age, dialysis for less than 6 months, and treatment with PD were predictive of anemia in this population.

Drug dosing during intermittent hemodialysis and continuous renal replacement therapy : special considerations in pediatric patients

Chronic renal failure is, fortunately, an unusual occurrence in children; however, many children with various underlying illnesses develop acute renal failure, and transiently require renal replacement therapy - peritoneal dialysis, intermittent hemodialysis (IHD), or continuous renal replacement therapy (CRRT). As children with acute and chronic renal failure often have multiple comorbid conditions requiring drug therapy, generalists, intensivists, nephrologists, and pharmacists need to be aware of the issues surrounding the management of drug therapy in pediatric patients undergoing renal replacement therapy. This article summarizes the pharmacokinetics and dosing of many drugs commonly prescribed for pediatric patients, and focuses on the management of drug therapy in pediatric patients undergoing IHD and CRRT in the intensive care unit setting. Peritoneal dialysis is not considered in this review. Finally, a summary table with recommended initial dosages for drugs commonly encountered in pediatric patients requiring IHD or CRRT is presented.

Tacrolimus vs. cyclosporine A as primary immunosuppression in pediatric renal transplantation: a NAPRTCS study

Using the North American Renal Transplant Cooperative Study (NAPRTCS) database, we performed a retrospective cohort study of 986 pediatric renal transplant recipients (index transplant 1997-2000) who were treated either with Cyclosporine A (CSA), Mycophenolate Mofetil (MMF) and steroids (n = 766) or tacrolimus (TAC), MMF and steroids (n = 220) to examine potential difference in clinical outcomes between these two groups. In the first year post-transplant, time to first rejection (29.1% vs. 29%, p = 0.840), risk for rejection [Adjusted Relative Risk (aRR) 1.01, 95% Confidence Interval (CI) 0.77, 1.323], graft survival (96.8% vs. 97.9%, p = 0.607) and risk for graft failure (aRR 0.988, 95% CI 0.64, 1.928) were not significantly different in TAC and CSA-treated patients. At 2 yr post-transplant, there was also no difference in risk for rejection (aRR 0.918, 95% CI 0.669, 1.259), graft survival (91.4% vs. 95.1%, p = 0.152) and risk for graft failure (aRR 0.702, 95% CI 0.461, 1.762) in the subset of 391 CSA-treated patients and 77 TAC-treated patients on whom 2 yr follow data were available in the database. TAC-treated patients were significantly less likely to require antihypertensive medication at 1 yr [aRR 0.74 (95% CI 0.454, 0.637)] and 2 yr post-transplant [aRR 0.67 (95% CI 0.56, 0.793)]. At 1 yr post-transplant, TAC-treated patients enjoyed a higher mean GFR as estimated by the Schwartz formula [89.1 mL/min/1.73 m(2) (SE 2.64) vs. 78.6 mL/min/1.73 m(2) (SE 1.07), p = 0.0003]. In addition, in the subset of patients with 2 yr of follow-up, TAC patients had a higher mean GFR at both 1 yr [98.6 mL/min/1.73 m(2) (SE 3.83) vs. 78.0 mL/min/1.73 m(2) (SE 1.44), p = 0.0003] and 2 yr post-transplant [96.7 mL/min/1.73 m(2) (SE 3.33) vs. 73.2 mL/min/1.73 m(2) (SE 1.48), p < 0.0001]. In summary, TAC and CSA, in combination with MMF and steroids, produce similar rejection rates and graft survival in pediatric renal transplant recipients. However, TAC is associated with improved graft function at 1 and 2 yr post-transplant. Further analysis as more patient data are obtained will be necessary to determine if this difference in graft function persists and translates into improved graft survival.

Varicella vaccination in children with nephrotic syndrome: a report of the Southwest Pediatric Nephrology Study Group

OBJECTIVE

To evaluate the safety and immunogenicity of varicella vaccine in children with nephrotic syndrome, including those taking low-dose, alternate-day prednisone.

STUDY DESIGN

Prospective, open-label, multicenter clinical trial of varicella vaccine in a 2-dose regimen in US and Canadian children (12 months to <18 years) with nephrotic syndrome. Varicella Zoster Virus (VZV) antibody levels were measured after the first and second vaccine dose and yearly for 2 years. Patients were monitored for adverse reactions to vaccine, exposure to varicella, dermatomal zoster, and chickenpox.

RESULTS

Twenty-nine children, mean age 4.9 (SD 1.9) years, 45% receiving every-other-day steroids, received 2 vaccine doses. All patients seroconverted and had VZV antibody levels considered protective against breakthrough varicella (>or=5 gpELISA units) after 2 doses. At 2-year follow-up, all patients retained detectable antibody, and 91% (21 of 23) had levels >or=5 gpELISA units. There were no adverse events associated with vaccination.

CONCLUSIONS

Varicella vaccine was generally well tolerated and highly immunogenic in children with nephrotic syndrome, including those on low-dose, alternate-day prednisone.

Varicella vaccination in children with chronic renal failure. A report of the Southwest Pediatric Nephrology Study Group

Children with kidney disease are at risk for serious varicella-related complications. To evaluate the safety and immunogenicity of a two-dose regimen of varicella vaccine in children (aged 1-19 years) with chronic renal insufficiency and on dialysis, the Southwest Pediatric Nephrology Study Group (SPNSG) undertook an open-label, multi-center, prospective 3-year clinical trial. Ninety-six patients without history of varicella were enrolled. Fifty (mean age 4.2 years) had no detectable varicella zoster virus (VZV) antibody; 98% seroconverted after the two-dose regimen. At 1, 2, and 3 years' follow-up, all patients studied maintained VZV antibody, including 16 who received a transplant. No significant vaccine-associated adverse events were seen. One subject developed mild varicella (10-50 maculopapular lesions) 16 months post transplant. In multivariate regression analysis, patients vaccinated after age 6 years had VZV antibody levels 73% (95% confidence interval 33%-89%) lower than patients vaccinated before age 6 years after controlling for gender, estimated glomerular filtration rate, and dialysis treatment. Adjusted analysis also showed that VZV antibody levels were lower after kidney transplantation, but this appeared to be a transient phenomenon. In this study, varicella vaccination with a two-dose regimen of varicella vaccine was generally well tolerated and highly immunogenic in children with chronic kidney disease.

Effects of patient compliance, parental education and race on nephrologists' recommendations for kidney transplantation in children

Transplantation is the treatment goal for youth with kidney failure. To assess the effects of compliance, parental education and race on nephrologists' recommendations for transplantation in children, we surveyed a national random sample of adult and pediatric nephrologists. We elicited transplant recommendations for case vignettes created from random combinations of patient age, gender, race, cause of renal failure, family structure, parental education and compliance. Of 519 eligible physicians, 316 (61%) responded. Nephrologists were more likely to recommend transplantation for children of college-educated parents than children of parents who did not finish high school, despite identical clinical and demographic characteristics (adjusted OR 1.48, 95% CI 1.18, 1.86). Patient noncompliance negatively influenced transplant recommendations (adjusted OR 0.1, 95% CI 0.08, 0.13). Additionally, compliance had a different effect on transplant recommendations for white compared with black patients. The adjusted OR of a white, compliant patient being referred for transplantation were twice that of a black compliant patient (OR 2.06, 95% CI 1.17, 3.6). Education and compliance with therapy independently influence nephrologists' recommendations for transplantation in youth with kidney failure. Among the most compliant candidates, referral for transplantation may vary with patient race.

Kidney stones, carbonic anhydrase inhibitors, and the ketogenic diet

PURPOSE

Because carbonic anhydrase inhibitors and the ketogenic diet are each known risk factors for kidney stones, simultaneous use of these therapies has been discouraged. The objective of this study was to establish the prevalence of nephrolithiasis in children in this combination-therapy population.

METHODS

Since 1996, 301 children have been started on the ketogenic diet at our institution. A retrospective cohort study of renal calculi in ketogenic diet patients was performed to evaluate the increased risk with combined use of a carbonic anhydrase inhibitor.

RESULTS

In 15 (6.7%) of 221 children on the ketogenic diet without the use of carbonic anhydrase inhibitors, stones developed. In five (6.3%) of the 80 children on the diet in combination with topiramate or zonisamide, stones developed. There was no difference between these two groups (p = 0.82). No child was treated with either acetazolamide or more than one carbonic anhydrase inhibitor simultaneously. Prior ketogenic diet duration was shorter (10.4 vs. 22.4 months; p = 0.03), and more children had either a family history of renal stones or significant urologic abnormalities (80 vs. 27%; p = 0.04) in the combination-therapy group.

CONCLUSIONS

The combined use of carbonic anhydrase inhibitors and the ketogenic diet does not increase the risk of kidney stones. We recommend that all patients treated with combination therapy should be treated with increased hydration. Urine alkalinization should be considered for children with previous renal abnormalities, family histories of kidney stones, hematuria, or elevated urine calcium-to-creatinine ratios. If renal stones are found, we advocate discontinuation of the carbonic anhydrase inhibitor.

Growth failure, risk of hospitalization and death for children with end-stage renal disease

Growth failure remains a significant problem for children with chronic renal insufficiency and end-stage renal disease (ESRD). We examined whether growth failure is associated with more-frequent hospitalizations or higher mortality in children with kidney disease. We studied data on prevalent United States pediatric patients with ESRD in 1990 who were followed through 1995. Patients were categorized according to the standard deviation score (SDS) of their incremental growth during 1990: severe (<-3 SDS), moderate growth failure (>-3 and <-2 SDS), and normal growth (>-2 SDS). Among 1,112 prevalent pediatric dialysis and transplant patients (<17 years, Tanner I-IV), those with severe and moderate growth failure had higher hospitalization rates [relative risk (RR) 1.14 [95% confidence interval (CI) 1.1, 1.2] and 1.24 [95% CI 1.2, 1.3]] respectively than those with normal growth after adjustment for age, gender, race, cause and duration of ESRD, and treatment modality (dialysis or transplant) in 1990. Kaplan-Meier survival analysis showed 5-year survival of 85% and 90% for patients with severe and moderate growth failure, respectively, compared with 96% for patients with normal growth ( P<0.001, log-rank). Cox proportional hazards analysis revealed that those with severe (RR 2.9, 95% CI 1.6, 5.3) and moderate growth failure (RR 2.01, 95% CI 1.1, 3.6) had an increased risk of death compared with youths with normal growth, after adjustment. A higher proportion of deaths in the severe and moderate growth failure groups were attributed to infectious causes (22% and 18.7%, respectively) than in the normal growth group (15.6%). We conclude that growth failure is associated with a more-complicated clinical course and increased risk of death for children with kidney failure.

Adverse clinical outcomes associated with short stature at dialysis initiation: a report of the North American Pediatric Renal Transplant Cooperative Study

OBJECTIVE

We examined whether height less than the 1% for age (z score <-2.5) at dialysis initiation predicts adverse clinical outcomes for children with kidney failure.

DESIGN

National cohort study of children initiating dialysis, followed for a minimum of 1 month to a maximum of 8 years.

SETTING

Voluntary consortium of pediatric nephrology centers across the United States and Canada in the North American Pediatric Renal Transplant Cooperative Study.

PATIENTS

Two thousand three hundred six patients </=21 years old initiated on dialysis between 1992 and 2000. Outcome Measures. School attendance, transplant wait listing, hospitalization rates, and survival.

RESULTS

Although there were no differences in transplant wait listings, school-aged children with short stature were less likely to be attending school full-time than were their counterparts with more normal height, even if medically capable. Short-stature patients have significantly more hospital days per month of dialysis follow-up than those patients with better growth (mean: 1.92 vs 1.58; median: 0.73 vs 0.44 hospital days per month of follow-up). Cox proportional hazards regression analyses show that children with height <1% for age have a twofold higher risk of death than those with more normal height, even after controlling for patient age, race, gender, cause of end-stage renal disease, wait list status, and dialysis modality.

CONCLUSIONS

Poor growth during chronic renal insufficiency leading to short stature at dialysis initiation is a marker for a more complicated clinical course for children with kidney failure. Aggressive nutritional support and early referral to a nephrologist to optimize growth may improve long-term outcomes for children with chronic kidney disease.

Varicella vaccination in pediatric kidney transplant candidates

Existing studies support the use of varicella vaccine in a two-dose regimen in patients with renal disease prior to transplantation. Levels of anti-varicella zoster virus antibody should be monitored on a regular basis after immunization, and where a loss of a previously protective antibody titer occurs, a third booster dose should be considered pretransplant. Further data need to be collected regarding the use of the vaccine in seronegative patients who have already undergone transplantation.

Does growth retardation indicate suboptimal clinical care in children with chronic renal disease and those undergoing dialysis?

Growth failure is an important problem for children with end-stage renal disease (ESRD). Patients receiving replacement therapy for longstanding renal failure since childhood are likely to report dissatisfaction with certain aspects of their lives, especially with final adult height. Additionally, recent data suggest that growth failure in children with ESRD is associated with adverse clinical outcomes, including more frequent hospitalizations, and increased mortality. Although poor growth is unlikely to be the cause of this increased morbidity, growth failure may be a marker for a group of patients at high risk of adverse events. In this review, the authors describe the prevalence of growth retardation in children in the US with chronic renal disease, and present recent data on morbidity associated with growth failure. After reviewing published reports documenting available strategies to optimize growth, the authors conclude that despite vigilance and aggressive clinical management, a subset of children with long-term renal insufficiency and ESRD may still have poor linear growth. A discussion of "optimal care" leads one to consider evidence of current variability in the management of growth retardation in ESRD, and the strengths and limitations of developing practice guidelines to optimize growth in this population.

The impact of dialysis and transplantation on children

Effective methods to treat end stage renal disease (ESRD) in children have become available in the United States during the last 3 decades. Since the United States Congress created the Medicare ESRD Program in 1972, most children with ESRD have the option of Medicare insurance. Medicare expenditures for children with ESRD range from $14,000 for transplant recipients to $43,000 for dialysis patients per year. The tremendous expense of ESRD treatment has led to research to determine which treatment options are associated with the best health outcomes and the best value (quality/cost) for the money spent treating ESRD. The National Kidney Foundation's Dialysis Outcomes Quality Initiative recommends the use of quality of life and health status measures to gauge the impact of renal replacement therapy on quality of life in the ESRD population. In adult patients with renal failure, several generic and disease-specific quality of life measures have been validated and tested for reliability. In contrast, little research using validated and reliable health status measures has been performed in pediatric patients to measure the impact of ESRD. This article summarizes existing literature on how we currently measure the impact of dialysis and transplantation on children, discusses existing health status measures for children and adolescents, and describes how these measures might be used to improve our care of patients and long-term outcomes for children with kidney failure.

Relation between pediatric experience and treatment recommendations for children and adolescents with kidney failure

CONTEXT

Children and adolescent patients with renal failure are frequently cared for by adult subspecialists. While peritoneal dialysis is used in less than 17% of adults with kidney failure, it is the preferred dialysis treatment for children. National data show that 45% of children receiving dialysis are treated with peritoneal dialysis and pediatric nephrologists report its use in 65% of patients receiving dialysis. Whether differences in peritoneal dialysis use among children are due to the pediatric experience of the clinician has not been examined.

OBJECTIVE

To assess whether the pediatric experience of nephrologists directly affects treatment recommendations for children with kidney failure.

DESIGN

Cross-sectional survey using 10 case vignettes per survey based on random combinations of 8 patient characteristics (age, sex, race, distance from facility, cause of renal failure, family structure, education, and compliance).

SETTING AND PARTICIPANTS

National random sample of office-, hospital-, and academic medical center-based adult and pediatric nephrologists, stratified by geographic region and conducted June to November 1999. Of 519 eligible physicians, 316 (61%) responded, including 191 adult and 125 pediatric nephrologists.

MAIN OUTCOME MEASURE

Treatment recommendations for peritoneal dialysis vs hemodialysis, compared based on nephrologists' pediatric experience.

RESULTS

After controlling for patient characteristics, pediatric nephrologists were 60% more likely than adult nephrologists to recommend peritoneal dialysis for identical patients (odds ratio, 1.61; 95% confidence interval, 1.35-1.92). This was true regardless of dialysis training, years in practice, practice setting, geography, or patient characteristics.

CONCLUSIONS

Our data indicate that pediatric specialization of clinicians influences treatment recommendations for children and adolescents with end-stage renal disease. Referring children to adult subspecialists may lead to differences in treatment choices and processes of care.

Peritoneal dialysis catheter infections and peritonitis in children: a report of the North American Pediatric Renal Transplant Cooperative Study

Peritonitis and catheter-related infections remain the two most-common causes of peritoneal dialysis (PD) treatment failure. To define the frequency and risks associated with exit site/tunnel infections (ESI/TI), as well as peritonitis, in pediatric patients on PD, we undertook a retrospective cohort study of patients initiated on PD in the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS). We examined demographic data and PD catheter characteristics of 1,258 patients, aged < or = 21 years, initiated on PD from 1992 to 1997. We examined the frequency and complications of ESI/TI occurring within 30 days, 6 months, and 1 year of follow-up. For peritonitis episodes, we examined patient risk factors for peritonitis. Almost 11% of patients had an ESI/TI at 30 days, 26% between 30 days and 6 months, and 30% between 6 months and 1 year of follow-up. There was no increased risk of ESI/TI associated with patient age, race, or catheter characteristics. Peritonitis occurred in dialysis patients at a rate of 1 episode per 13.2 patient months. Proportional hazards regression analysis demonstrated that black race, single-cuffed catheters, and upward pointing exit sites were independent risk factors for peritonitis in the pediatric PD population. Patients with ESI/TI had twice the risk of those without these infections of developing peritonitis or needing access revision, and an almost threefold increased risk of hospitalization for access complications/malfunction. ESI/TI occurs commonly in pediatric PD patients. These infections cause significant morbidity, through risk of peritonitis, access revision, and hospitalization for catheter complications. Further study of potentially modifiable risk factors for ESI/TI in pediatric end-stage renal disease patients is warranted.

Risk factors for urolithiasis in children on the ketogenic diet

Kidney stones have been associated with use of the ketogenic diet in children with refractory seizure disorders. We performed a case-control study examining risk factors for the development of stones on the ketogenic diet, and prospectively followed children initiating the ketogenic diet to evaluate the incidence of urolithiasis. Clinical characteristics of 18 children presenting with stones (8 uric acid stones, 6 mixed calcium/uric acid stones, 1 calcium oxalate/phosphate stone, 3 stones not evaluated) were compared with characteristics of non-stone-forming children initiating the ketogenic diet at Johns Hopkins since July 1996. Since July 1996, 112 children initiating the ketogenic diet have been followed for development of stones. Follow-up times on the diet range from 2 months to 2.5 years. Of 112 children, 6 have developed stones (3 uric acid, 3 mixed calcium/uric acid stones) (0.8 children developing stones/ 100 patient-months at risk). Comparisons of children presenting with stones on the ketogenic diet with characteristics of the entire cohort initiating the ketogenic diet suggest younger age at diet initiation and hypercalciuria are risk factors for the development of stones. Prospective evaluation of children initiating the ketogenic diet revealed that almost 40% of patients had elevated fasting urine calcium: creatinine ratios at baseline; this increased to 75% after 6 months on the diet. Median urine pH was 5.5 at diet initiation, and remained at 6.0 thereafter. In a subset of patients tested, urinary citrate excretion fell from a mean of 252 mg/24 h pre diet initiation to 52 mg/24 h while on the diet. Uric acid excretion remained normal. Patients maintained on the ketogenic diet often have evidence of hypercalciuria, acid urine, and low urinary citrate excretion. In conjunction with low fluid intake, these patients are at high risk for both uric acid and calcium stone formation.

Racial differences in access to the kidney transplant waiting list for children and adolescents with end-stage renal disease

CONTEXT

Renal transplantation is the treatment of choice for pediatric patients with end-stage renal disease (ESRD). Black patients wait longer for kidney transplants than do white patients.

OBJECTIVE

To determine whether the increased time to transplantation for black pediatric patients is attributable not only to a shortage of suitable donor organs, but also to racial differences in the time from a child's first treatment for ESRD until activation on the cadaveric kidney transplant waitlist.

DESIGN

National longitudinal cohort study.

SETTING

US Medicare-eligible, pediatric ESRD population.

PATIENTS

Children and adolescents </=19 years old at the time of their first dialysis for ESRD between 1988 and 1993, followed through 1996. Patients who received living donor renal transplants were excluded from study.

MAIN OUTCOME MEASURES

Time from first dialysis for ESRD until activation on the kidney transplant waiting list, relative hazard of activation on the waiting list for black compared with white pediatric patients.

RESULTS

Comparisons of the time from first dialysis for ESRD to waitlisting among the 2162 white (60.7%) and 1122 black (31.5%) patients studied using survival analysis revealed that blacks were less likely to be waitlisted at any given time in follow-up. In multivariate analysis, even after controlling for patient age, gender, socioeconomic status, geographic region, incident year of renal failure, and cause of ESRD, blacks were 12% less likely to be waitlisted than were whites at any point in time (relative hazard:. 88: 95% confidence interval:.79-.97).

CONCLUSIONS

Racial disparities in access to the renal transplant waiting list exist in pediatrics. Whether these disparities are attributable to differences in time of presentation to a nephrologist, physician bias in identification of transplant candidates, or patient preferences warrants further study.

Impact of gender on access to the renal transplant waiting list for pediatric and adult patients

While the public and policy-makers place a priority on equity in the organ allocation process, several studies suggest that women may be less likely than men to receive a renal transplant. However, the cause of this disparity and whether it exists among children with end-stage renal disease (ESRD) are unknown. To address these issues, two nationally representative cohorts of incident patients were examined: (1) 7594 adults with ESRD onset between 1986 and 1993 for whom detailed data were available from the medical record on health status; and (2) 3217 patients <20 yr old who developed ESRD between 1988 and 1993. Patients were followed from initiation of dialysis for up to 10 yr until first activation on the United Network of Organ Sharing renal transplant waiting list. Access to the list for female and male patients with ESRD was compared using Cox proportional hazards models with adjustment for demographic, socioeconomic, and clinical factors. Crude rates of wait-listing per 100 person-years of ESRD were lower for female patients than male patients in both the pediatric (28.89 versus 34.18) and adult (3.94 versus 6.54) populations. Despite adjustment for numerous confounding factors, this gender-based disparity persisted in multivariate analysis. Among children with ESRD, female patients were 14% less likely to be listed than male patients (relative hazard [RH] 0.86; 95% confidence interval [CI], 0.78 to 0.93), and in the adult group, women were 18% less likely to be activated for transplant than men (RH 0.82; 95% CI, 0.72 to 0.93). These findings suggest that female patients of all ages with ESRD face barriers in being activated for cadaveric renal transplantation. Greater attention to this issue is necessary to improve equity in the organ allocation system and potentially improve the outcomes of female patients with ESRD.

Septicemia in diabetic hemodialysis patients: comparison of incidence, risk factors, and mortality with nondiabetic hemodialysis patients

Diabetes mellitus is the most common cause of treated end-stage renal disease (ESRD), and diabetic hemodialysis patients have a high mortality rate. To identify differences in risk of septicemia among diabetic and nondiabetic hemodialysis patients, we examined the incidence, risk factors, and mortality for septicemia in a large sample of the US hemodialysis population. We performed a longitudinal cohort study of the incidence and risk factors for hospitalized cases of septicemia in diabetic and nondiabetic hemodialysis patients using baseline data from the US Renal Data System case-mix severity study with 7-year follow-up from hospitalization and death records. Independent risk factors for septicemia were assessed using Poisson regression. Independent effect of septicemia on mortality was assessed using Cox proportional hazards analysis. Over 7 years, 11.1% of nondiabetic patients and 12.5% of diabetic patients experienced at least one episode of septicemia. Older age and low serum albumin were independent risk factors for septicemia in all patients. In diabetics, white race, peripheral vascular disease, and hemodialyzer reuse, particularly in type 1, were independent risk factors. In nondiabetics, coronary artery disease, cerebrovascular disease, and temporary and permanent catheters were associated with an increased risk. In both groups, patients who experienced an episode of septicemia had twice the risk of death from any cause and an eightfold risk of death from septicemia. Septicemia occurs equally frequently and carries a marked increased risk of death in both nondiabetic and diabetic hemodialysis patients. Improving nutritional status and minimizing the use of catheters might help ameliorate the risk of septicemia. In diabetics, aggressive treatment of peripheral vascular disease might help reduce the risk of septicemia. Further research to elucidate potential mechanisms for variations in risk for septicemia according to race and hemodialyzer reuse practices are warranted in diabetic patients.

For-profit versus not-for-profit dialysis care for children with end stage renal disease

OBJECTIVE

Over the last 2 decades, for-profit dialysis units have become the most common providers of renal replacement therapy for adults with end stage renal disease (ESRD) and have had an increasing role in the dialysis of children. We undertook a study to determine whether dialysis facility profit status influences the choice of dialysis therapy in the pediatric population.

DESIGN

Cross-sectional study of national data from the Health Care Financing Administration.

SETTING

Free-standing and hospital-based outpatient dialysis facilities in the United States.

PATIENTS

A total of 1568 children and adolescents (</=19 years of age) eligible for US Medicare ESRD benefits in 1994.

OUTCOME MEASURES

The association between dialysis modality choice and the profit status of the facility. Crude associations were estimated by the OR of a patient being treated with peritoneal dialysis (PD) versus hemodialysis at nonprofit versus for-profit facilities. Adjusted associations were estimated using logistic regression analysis.

RESULTS

In bivariate analysis, children with ESRD dialyzed at nonprofit facilities were nearly three times as likely as those at for-profit facilities to be on PD (OR: 2.9; 95% CI: 2.3,3.6). In multivariate analysis, after controlling for patient age, sex, race, cause and duration of ESRD, free-standing versus hospital-based facility, and the pediatric expertise of the facility, patients at nonprofit facilities were more than twice as likely as those dialyzed at for-profit facilities to be on PD (OR: 2.3; 95% CI: 1.6, 3.4). After taking into account the clustering of patients within facilities, the association between nonprofit status and the use of PD persisted (OR: 2.2; 95% CI: 1.5,3.2).

CONCLUSIONS

Children with ESRD treated at nonprofit facilities are more likely to receive PD than are those treated at for-profit facilities even after controlling for other patient and facility characteristics. This finding suggests that clinical decision making for pediatrics may be influenced by the ownership of the health care facility in which the patient is treated.

Septicemia in dialysis patients: incidence, risk factors, and prognosis

BACKGROUND

Infection is second to cardiovascular disease as a cause of death in patients with end-stage renal disease (ESRD), and septicemia causes a majority of these infectious deaths. To identify patients at high risk and to characterize modifiable risk factors for septicemia, we examined the incidence, risk factors, and prognosis for septicemia in a large, representative group of U.S. dialysis patients.

METHODS

We conducted a longitudinal cohort study of incident ESRD patients in the case-mix study of the U.S. Renal Data System with seven years of follow-up from hospitalization and death records. Poisson regression was used to examine independent risk factors for hospital-managed septicemia. Cox proportional hazards analysis was used to assess the independent effect of septicemia on all-cause mortality and on death from septicemia. Separate analyses were performed for patients on peritoneal dialysis (PD) and hemodialysis (HD).

RESULTS

Over seven years of follow-up, 11.7% of 4005 HD patients and 9.4% of 913 PD patients had at least one episode of septicemia. Older age and diabetes were independent risk factors for septicemia in all patients. Among HD patients, low serum albumin, temporary vascular access, and dialyzer reuse were also associated with increased risk. Among PD patients, white race and having no health insurance at dialysis initiation were also risk factors. Patients with septicemia had twice the risk of death from any cause and a fivefold to ninefold increased risk of death from septicemia.

CONCLUSIONS

Septicemia, which carries a marked increased risk of death, occurs frequently in patients on PD as well as HD. Early referral to a nephrologist, improving nutrition, and avoiding temporary vascular access may decrease the incidence of septicemia. Further study of how race, insurance status, and dialyzer reuse can contribute to the risk of septicemia among ESRD patients is indicated.

Effect of parental donor sex on rejection in pediatric renal transplantation: a report of the North American Pediatric Renal Transplant Cooperative Study

Using the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) database, we performed a retrospective cohort study of 1,552 pediatric renal transplant patients who had received a graft from a biological parent to determine if parental donor sex influences the development of rejection. There were 102/675 (15.1%) graft failures in paternal grafts compared to 144/877 (16.4%) graft failures in maternal grafts. Overall graft survival (p=0.48) and time to first rejection (p>0.9) were not different in patients receiving paternal versus maternal grafts. The overall frequency of graft loss to rejection was also not different. However, maternal donation was associated with a significantly longer time to first rejection in patients less than one year of age at the time of transplantation (p=0.01). Time to first rejection was not different between maternal and paternal grafts in older recipients. In summary, the present study did not demonstrate a difference in graft survival between maternal and paternal donations, but the youngest patients may experience a longer time to first rejection with maternal donation. The number of young patients is small, however, and further data are necessary to confirm this observation.

Antibody levels to diphtheria, tetanus, and rubella in infants vaccinated while on PD: a Study of the Pediatric Peritoneal Dialysis Study Consortium

To determine whether infants who receive routine childhood immunizations while on chronic peritoneal dialysis (CPD) develop protective antibody levels/titers, we measured antibody levels/titers in infants vaccinated with diphtheria/tetanus/pertussis (DTP) and measles/mumps/rubella (MMR) while on CPD. Eight CPD patients (median age 19 months, range 9-39 months) had measurement of antibody to diphtheria and tetanus toxoids. Seven of the 8 (88%) had protective levels of IgG antibody to both toxoids. The single patient who did not have protective antibody to either diphtheria or tetanus had a low total serum IgG. However, 3 other patients who had low IgG had protective antibody levels. Serial measurements of antibody to tetanus and diphtheria were obtained in 3 of the 8 patients. All maintained protective levels to both diphtheria and tetanus toxoids for as long as 24 months postvaccination. Antibody to rubella was also measured in 5 CPD patients (median 29 months, range 19-39 months), and all had protective antibody titers despite the fact that 3 had low total serum levels. In conclusion, most but not all infants immunized while on CPD have protective antibody levels/titers to diphtherial, tetanus, rubella. Alteration of the routine schedule for immunizations does not appear to be necessary. However, periodic measurements of antibody may be indicated, particularly to live vial vaccines, prior to transplantation.

Evaluation of neurotoxicity in pediatric renal transplant recipients treated with tacrolimus (FK506)

The presence of severe and mild neurotoxicity in our pediatric renal transplant recipients treated with tacrolimus was determined by chart review (severe neurotoxicity) and patient survey (mild neurotoxicity). 14 patients were studied (mean age 15 yr, 5 month, +/- 4.4 yr). 1 patient experienced seizures, felt to be related to malignant hypertension. No other episode of severe neurotoxicity was documented. Most patients (12/14) reported at least one mild neurologic symptom, and half stated their symptoms were present at least 'most of the time'. The most frequent complaints were myalgias (7/14, 50%) and tremors (7/14, 50%) followed by fatigue (5/14, 38%). Severe neurotoxicity may be relatively infrequent in pediatric renal transplant patients treated with tacrolimus. Milder neurologic complaints may be commonly seen in this population, but in general are not severe enough to cause discontinuation of tacrolimus.

Immunization practices in children with renal disease: a report of the North American Pediatric Renal Transplant Cooperative Study

To determine the current immunization recommendations of practicing pediatric nephrologists, a questionnaire was sent to the members of the North American Pediatric Renal Transplant Cooperative Society. Sixty-two percent of the centers responded. The results of the survey suggest that although consensus for approaching immunization does exist, recommendations do vary from center to center. Virtually all centers recommend standard vaccines [DTP, oral poliovirus (OPV), hepatitis B (Hep B), and Haemophilus influenzae B (Hib)] for their renal insufficiency and dialysis patients. Despite the fact that they are not infectious, standard killed vaccines (DTP, Hep B, Hib) are recommended less frequently for transplanted patients (86%) than their renal insufficiency (98%) and dialysis (near 100%) counterparts. Additionally, OPV and measles/mumps/rubella (MMR), both live viral vaccines, are rarely recommended post transplant. Almost 90% of centers recommend the use of influenza vaccine, while only 60% of centers recommend pneumococcal vaccine for children with renal disease. Over 70% of centers recommend the newly licensed varicella vaccine for patients on dialysis and those with renal insufficiency. Between 5% and 12% of centers recommend live viral vaccines, including OPV, MMR, and varicella vaccine, for immunosuppressed patients post renal transplant.

Varicella in the first year after renal transplantation: a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS)

Prior reports document that children with renal transplants are at risk of severe varicella, with a 5-25% mortality rate. We have examined the current incidence and mortality of varicella requiring hospitalization in pediatric patients in the first year after kidney transplantation through a multi-center retrospective cohort study. Data from the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) for 2320 pediatric patients who received renal transplants between 1987 and 1993 and were followed until 1995 were examined. Varicella requiring hospitalization in the first post-transplant year occurred in 44 children. Characteristics of the patients who developed varicella were compared to the rest of the NAPRTCS cohort using chi-square analysis. Kaplan-Meier estimates of graft survival were used to compare graft survival in varicella patients and other NAPRTCS patients. Varicella patients tended to be younger (p=0.09) and more often male (p=0.07, chi-square) than other NAPRTCS patients. None of the 44 patients with varicella in their first post-transplant year died from this infection. The number of episodes of acute rejection per transplant and the time to first rejection was not different in patients with varicella compared to the other NAPRTCS patients. Five-year graft survival was not different for varicella cases when compared to other NAPRTCS patients with grafts surviving at least 6 months post-transplant. We conclude that the mortality rate of patients hospitalized with varicella in the first post-transplant year and the risk of subsequent graft dysfunction may be significantly lower than previously described. However, varicella remains a significant cause of potentially avoidable hospitalization in the first post-transplant year. Further study of the safety and efficacy of varicella vaccination in children with renal insufficiency and those post-transplant is warranted.

Does greater pediatric experience influence treatment choices in chronic disease management? Dialysis modality choice for children with end-stage renal disease

OBJECTIVE

To determine whether treatment choice for children with end-stage renal disease varies with greater pediatric experience at the dialysis facility.

DESIGN

National cross-sectional study.

SETTING

Outpatient dialysis facilities throughout the United States.

PATIENTS

All children (age, < or = 19 years) undergoing dialysis in 1990, identified using the Medicare End-stage Renal Disease registry (1990 facility survey and quarterly dialysis records).

OUTCOME MEASURES

The odds of receiving peritoneal dialysis vs hemodialysis according to the pediatric experience of the facility. "Pediatric experience" for dialysis facilities was defined as the number of patients 19 years old or younger divided by the total number of patients treated at that facility. Adjustment, using multiple logistic regression, was made for differences in age, sex, cause and duration of end-stage renal disease, income, education, and facility characteristics.

RESULTS

In 1990, there were 1256 patients 19 years old or younger who underwent a single-treatment modality at a single facility for most of the year. Sixty-three percent (790/ 1256) were treated at facilities with fewer than 5% of patients younger than 19 years. Thirty-six percent were treated at centers with less than 1% of pediatric patients. In a multivariate analysis, pediatric experience in a facility was independently associated with the use of peritoneal dialysis in children. Children treated at facilities with more than 10% pediatric patients were 60% more likely to be treated with peritoneal dialysis rather than hemodialysis compared with children treated at facilities with fewer than 1% of pediatric patients, even after controlling for patient age, race, income, education, cause and duration of end-stage renal disease, and facility characteristics such as hospital-based vs independent unit and for-profit vs not-for-profit status (odds ratio, 1.6; 95% confidence interval, 1.1-2.3).

CONCLUSIONS

Children receiving care at dialysis facilities that have greater experience with pediatric patients are more likely to receive peritoneal dialysis than hemodialysis, a therapy with recognized clinical benefits for children that is inherently less resource intensive than is hemodialysis.

Racial differences in choice of dialysis modality for children with end-stage renal disease

OBJECTIVE

Black-white disparities in the use of specific medical and surgical services have been reported in adult populations. Such disparities are not well documented in children. We sought to determine whether racial disparities in the use of medical services exist among children with chronic illness who have similar health insurance, specifically the choice of dialysis modality for individuals with end-stage renal disease.

DESIGN

National cross-sectional study.

SETTING

Outpatient dialysis facilities throughout the United States.

PATIENTS AND PARTICIPANTS

All Medicare-eligible children (age, </=19 years) undergoing renal replacement therapy in 1990 in the United States, using data from the Medicare ESRD registry.

OUTCOME MEASURES

The odds of receiving hemodialysis versus peritoneal dialysis according to race. Adjustment was made for differences in age, gender, cause, and duration of end-stage renal disease, income, education, and facility characteristics using multiple logistic regression.

RESULTS

In 1990, 870 white and 368 black children received chronic (>1 year) renal replacement therapy in the United States. In bivariate analysis, blacks were two times (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.7, 2.8) more likely than whites to receive hemodialysis versus peritoneal dialysis. After controlling for other patient and facility characteristics in multivariate analysis, black children were still significantly more likely than white children to receive hemodialysis (OR, 2.4; 95% CI, 1.7, 3.5).

CONCLUSIONS

Black race is strongly associated with the use of hemodialysis in children. Family, patient, or provider preferences could account for the difference in choice of therapy by race.

Pneumococcal polysaccharide vaccine in children with chronic renal disease: a prospective study of antibody response and duration

We studied the antibody response to pneumococcal serotypes 3 and 14 after pneumococcal polysaccharide vaccine was administered to 41 children with renal disease. One month after vaccination, 76% and 61% of patients achieved at least a twofold titer rise to serotypes 3 and 14, respectively; this finding was comparable to historic control values. One year after vaccination, the majority of patients retained protective antibody levels. Achieving a titer > or = 1.0 microgram/ml IgG at 1 month was highly predictive of retaining a protective antibody level > or = 0.15 microgram/ml at 1 year.

Immune response to influenza vaccination in children with renal disease

Although immunization with influenza vaccine is recommended for children with chronic renal disease and after organ transplantation, the antibody response in these children has not been well described. We studied the response to the 1993-1994 trivalent influenza vaccine in children, aged 1-21 years, with chronic renal failure (n = 15), end-stage renal disease requiring dialysis (n = 10), and post renal transplantation (n = 17). Each group's antibody response was compared with that of a control group (n = 7). No significant differences were found in seroconversion rates, percentage of patients achieving protective hemagglutination-inhibition titers post vaccination or change in geometric mean titers from pre to post vaccination between study groups and controls. These results suggest that pediatric patients with renal disease will respond and therefore will benefit from currently recommended influenza immunization.