Obesity and renal transplant outcome: a report of the North American Pediatric Renal Transplant Cooperative Study

Priority setting in kidney transplantation: A qualitative study evaluating Swedish practices

Background: Transplantation is the treatment of choice for end-stage renal disease; it increases survival and quality of life, while being more cost-effective than dialysis. It is, however, limited by the scarcity of kidneys. The aim of this paper is to investigate the fairness of the priority setting process underpinning Swedish kidney transplantation in reference to the Accountability for Reasonableness (A4R) framework. Methods: Fifteen semi-structured interviews were carried out with transplant surgeons (7), nephrologists (6) and coordinators (2) representing centers nationwide. Collected data was analysed using thematic analysis. To assess fairness in the priority setting process, identified factors were assessed in the reference to the four conditions (publicity, relevance, revision and appeal, enforcement) forming the accountability for reasonableness framework. Results: Decision-making in assessment and allocation is based on clusters of factors. The factors appeal to various values, which are balanced against each other throughout the kidney allocation process: maximizing benefit, priority to the worst off and equality. The factors described by subjects and the values on which they rest satisfy the relevance condition of the accountability for reasonableness framework. However, two potential sources for unfair inequalities in access to treatment are identified: clinical judgment and institutional policies. Conclusions: The development of national guidelines both for assessing transplant candidacy, and for the allocation of kidneys from deceased donors, would contribute to standardize practices across centres; it will also help to better meet the conditions of fairness in reference to Accountability for Reasonableness. The benefits of this policy proposal in Swedish kidney transplantation merits consideration.

Left ventricular function in children and adults after renal transplantation in childhood

BACKGROUND

Renal transplantation improves left ventricular (LV) function, but cardiovascular mortality remains elevated. The aim of this cross-sectional study was to determine whether subclinical abnormalities of LV longitudinal function also persist in patients who underwent renal transplant in childhood.

METHODS

Conventional and speckle tracking echocardiography was performed in 68 renal transplant recipients (34 children and 34 adults, median 9.8 years (range 2.0-28.4 years) after first transplantation and 68 age- and sex-matched healthy controls.

RESULTS

Mean age at first transplantation was 8.8 ± 4.8 years. Forty-three percent had a pre-emptive transplant. Of the remaining, 70% received haemodialysis and 30% peritoneal dialysis on average for 6.9 months. Thirty-one percent of paediatric and 35% of adult patients had hypertension. LV mass index was increased in adult patients (92 ± 24 vs 75 ± 11 g/m(2), P< 0.01). LV diastolic function and exercise capacity were impaired in both paediatric and adult patients. LV longitudinal peak systolic strain and strain rate were comparable in patients and controls. In multivariate analysis, systolic blood pressure and LV diastolic relaxation were the main covariates of LV peak systolic strain and strain rate (all P < 0.01).

CONCLUSIONS

Patients who underwent renal transplantation in childhood have abnormal LV diastolic function and impaired exercise capacity, despite preserved LV longitudinal systolic deformation.

Cardiovascular disease in children with chronic kidney disease

More than a decade ago, cardiovascular disease (CVD) was recognized as a major cause of death in children with advanced CKD. This observation has sparked the publication of multiple studies assessing cardiovascular risk, mechanisms of disease, and early markers of CVD in this population. Similar to adults, children with CKD have an extremely high prevalence of traditional and uremia-related CVD risk factors. Early markers of cardiomyopathy, such as left ventricular hypertrophy and dysfunction, and early markers of atherosclerosis, such as increased carotid artery intima-media thickness, carotid arterial wall stiffness, and coronary artery calcification, are frequently present in these children, especially those on maintenance dialysis. As a population without preexisting symptomatic cardiac disease, children with CKD potentially receive significant benefit from aggressive attempts to prevent and treat CVD. Early CKD, before needing dialysis, is the optimal time to both identify modifiable risk factors and intervene in an effort to avert future CVD. Slowing the progression of CKD, avoiding long-term dialysis and, if possible, conducting preemptive transplantation may represent the best strategies to decrease the risk of premature cardiac disease and death in children with CKD.

Systemic arterial hypertension in children following renal transplantation: prevalence and risk factors

BACKGROUND

Control of blood pressure (BP) following renal transplantation may improve allograft and patient survival. Our aims were (i) to describe the distribution of BP and the prevalence of systolic and/or diastolic hypertension in children over the first 5 years following renal transplantation and (ii) to evaluate clinical risk factors and centre-specific factors associated with hypertension in this population.

METHODS

We conducted a retrospective case note review of all current paediatric kidney transplant patients in the UK, with data collected at 6 months, 1, 2 and 5 years following transplantation in subjects with hypertension (systolic and/or diastolic BP > 95th > ) and non-hypertensive subjects BP ≤ 95th > .

RESULTS

In total, 27.3% (117/428), 27.6% (118/428), 26.0% (95/365) and 25.6% (50/195) of the patients were hypertensive (systolic and/or diastolic BP > 95th > ) at 6 months, 1, 2 and 5 years following transplantation, respectively. A total of 58.4% of the patients at 6 months, 52.8% at 1 year, 48.2% at 2 years and 48.2% at 5 years were receiving anti-hypertensive therapy, of whom 31.6-36.6% remained hypertensive. When subjects were identified as being hypertensive, on anti-hypertensive medication or had untreated hypertension (systolic and/or diastolic BP > 95th > ), 66.4, 61.0, 56.4 and 55.9% of patients were hypertensive at 6 months, 1, 2 and 5 years, respectively. In a multivariate model, odds ratios for systolic hypertension were 4.16 (deceased versus living donor), 2.65 (lowest versus highest quartile of height z-score) and 2.07 (if on anti-hypertensive; yes versus no). There was significant variation in prevalent rates of hypertension between centres (P < 0.0001) that remained significant (P = 0.003) after adjustment for all the factors in the multivariate model.

CONCLUSIONS

Control of BP after kidney transplantation remains sub-optimal in paediatric centres in the UK. Just over 25% of patients remain hypertensive 5 years following transplantation. Significant differences between centres remain unexplained and may reflect differences in assessment and management of hypertension.

Prevalence and correlates of multiple cardiovascular risk factors in children with chronic kidney disease

BACKGROUND AND OBJECTIVES

Although prevalence of traditional cardiovascular risk factors (CVRF) has been described in children with CKD, the frequency with which these CVRF occur concomitantly and the clinical characteristics associated with multiple CVRF are unknown. This study determined the prevalence and characteristics of multiple CVRF in children in the Chronic Kidney Disease in Children study.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using cross-sectional data from first follow-up visits, we determined the prevalence of four CVRF: hypertension (casual BP >95(th) percentile or self-reported hypertension with concurrent use of anti-hypertensive medication), dyslipidemia (triglycerides >130 mg/dl, HDL <40 mg/dl, non-HDL >160 mg/dl, or use of lipid-lowering medication), obesity (BMI >95(th) percentile), and abnormal glucose metabolism (fasting glucose >110 mg/dl, insulin >20 μIU/ml, or HOMA-IR >2.20, >3.61, or >3.64 for those at Tanner stage 1, 2 to 3, or 4 to 5, respectively) in 250 children (median age 12.2 years, 74% Caucasian, median iohexol-based GFR 45.2 ml/min per 1.73 m(2)).

RESULTS

Forty-six percent had hypertension, 44% had dyslipidemia, 15% were obese, and 21% had abnormal glucose metabolism. Thirty-nine percent, 22%, and 13% had one, two, and three or more CVRF, respectively. In multivariate ordinal logistic regression analysis, glomerular disease and nephrotic-range proteinuria were associated with 1.96 (95% confidence interval, 1.04 to 3.72) and 2.04 (95% confidence interval, 0.94 to 4.43) higher odds of having more CVRF, respectively.

CONCLUSIONS

We found high prevalence of multiple CVRF in children with mild to moderate CKD. Children with glomerular disease may be at higher risk for future cardiovascular events.

Extremes of weight centile are associated with increased risk of mortality in pediatric intensive care

Introduction

Although numerous studies have linked extremes of weight with poor outcome in adult intensive care patients, the effect of weight on intensive care outcome has not previously been reported in the pediatric population. The aim of this study was to investigate the relationship between admission weight centile and risk-adjusted mortality in pediatric intensive care patients.

Methods

Data were collected on 6337 consecutively admitted patients over an 8.5 year period in a 15 bed pediatric intensive care unit (ICU) located in a university-affiliated tertiary referral children's hospital. A weight centile variable was entered into a multivariate logistic regression model that included all other pediatric index of mortality (PIM-2) variables, in order to determine whether weight centile was an independent risk factor for mortality.

Results

Weight centile was associated with mortality in both univariate and multivariate analysis, with the lowest mortality being associated with weights on the 75^th centile and increasing symmetrically around this nadir. A transformed weight centile variable (absolute value of weight centile-75) was independently associated with mortality (odds ratio 1.02, P = 0.000) when entered into a multivariate logistic regression model that included the PIM-2 variables.

Conclusions

In this single-center cohort, weight centile was an independent risk factor for mortality in the ICU, with mortality increasing for patients at either end of the weight spectrum. These observations suggest that the accuracy of mortality prediction algorithms may be improved by inclusion of weight centile in the models. A prospective multicenter study should be undertaken to confirm our findings.

Challenges in pediatric transplantation: the impact of chronic kidney disease and cardiovascular risk factors on long-term outcomes and recommended management strategies

Barriers to successful outcomes following pediatric transplantation have shifted from ischemic reperfusion injury and rejection to more long-term complications. Of particular concern is the high prevalence of CKD owing to preexisting damage and nephrotoxicity, as well as other CV complications such as hypertension and cardiomyopathy. All of these contribute to graft loss and shortened life expectancy, thereby limiting the success story of solid-organ transplantation. Managing CKD and related CV morbidity should be integral to the care of pediatric transplant patients, and timely detection of any irregularities would increase the chances of restoring lost kidney function. GFR is still the widely accepted indicator of renal function, and nuclear medicine techniques are the gold standard measurement methods. These methods are limited by costs, radiation exposure and substrate injection, and current practice still uses the Schwartz estimate, despite its well-documented limitations. Newer endogenous markers of GFR, such as cystatin C clearance, give a more accurate measure of true GFR but have not been embraced in the management of pediatric transplant recipients. Furthermore, indirect markers (e.g., microalbuminuria and hypertension) could also aid early detection of renal damage. The effects of mainstay immunosuppressants on kidney and heart function are varied, with available data indicating favorable outcomes with tacrolimus compared with ciclosporin. There is a need for appropriately designed and powered randomized controlled trials to validate innovative concepts for tailored immunosuppression in the pediatric population. To date, very few studies have generated long-term data in pediatric renal transplant patients - results of 1-4-yr study favored tacrolimus over ciclosporin, but other immunosuppressive agents also need to be evaluated.

Impact of obesity on children undergoing liver transplantation

Controversies exist with respect to the mortality of patients undergoing liver transplantation at the extremes of the body mass index (BMI). For pediatric liver transplantation, weight is usually the only factor considered in survival analysis. A review of the United Network for Organ Sharing database (1987-2007) revealed 9701 pediatric patients (<18 years old) who underwent primary liver transplantation. Patients were stratified into 5 BMI categories established by the World Health Organization according to their Z score, which was based on age, gender, and BMI: -3, -2, 0, +2, and +3. The survival rates in these 5 categories were compared with Kaplan-Meier survival curves and log-rank testing. Patients with thinness (Z score = -2) and severe thinness (Z score = -3) had significantly (P < 0.0001) lower survival at 1 year (84.4%) versus the survival (88.7%) of the normal and overweight groups (Z score = 0 and Z score = + 2, respectively). For patients with obesity (Z score = +3), there was no significant difference in survival early after transplantation, but their mortality gradually increased in the later years after transplantation. By 12 years after liver transplantation, the obese group had significantly (P = 0.04) lower survival (72%) than the normal and overweight groups (77%). In conclusion, liver transplantation holds increased risk for obese pediatric patients. Thin pediatric patients experience early mortality after liver transplantation, and obese pediatric patients experience late mortality after liver transplantation. Transplant management can be modified to optimize the care of these patients.

Cardiorespiratory fitness is a marker of cardiovascular health in renal transplanted children

Children with renal transplants (TX) are at increased risk of cardiovascular (CV) disease. Study objectives were to assess the level of cardiorespiratory fitness (CR fitness) and daily physical activity (PA) in renal TX children and adolescents in relation to traditional cardiovascular risk factors. Laboratory testing included assessment of CR fitness by treadmill exercise testing (VO(2peak)), 24-h ambulatory blood-pressure (ABPM) measurement, oral glucose tolerance test (OGTT), anthropometrics and measurement of lipid levels. PA was self-reported by questionnaire. Twenty-two TX patients with a median (range) age 14.5 (9-18) years were tested. Median V0(2peak) was 66% (36-97) of the expected values compared with controls. Nineteen (86%) children reported <60 min of daily moderate to vigorous physical activity (MVPA). Sixteen (73%) were hypertensive and 8 (34%) were overweight or obese. Four children fulfilled the criteria for a metabolic syndrome. Children with at least 2 of the 3 metabolic risk factors (hypertension, overweight, and glucose intolerance, n=7) achieved significantly lower VO(2peak) compared with those with one or none of these factors (median V0(2peak) 45% and 73% of the expected values respectively, p=0.003). Renal TX children and adolescents have severely impaired CR fitness and PA. Reduced CR fitness was associated with the clustering of CV risk factors. Routine counseling for increased PA is strongly recommended.

Outcome of pediatric renal transplantation in north India

We report our experience and long-term outcome of pediatric renal transplantation at a referral center in New Delhi. During 1995-2008, 45 transplants were performed in 43 patients at a mean age of 13.3 ± 4.0 (range 3.8-18) yr. The chief causes for ESRD were reflux nephropathy, obstructive uropathy, vasculitis, renal dysplasia, and focal segmental glomerulosclerosis. Most (91.1%) donors were living related. Post-transplant immunosuppression comprised prednisolone, a calcineurin inhibitor and azathioprine or MMF. AR and CR were seen in 14 (31.1%) and 12 (26.7%) allografts, respectively. Predictors of CR were unsatisfactory compliance and multiple episodes of AR (p = 0.002 each). Urinary infections (n = 13), septicemia (4), tuberculosis (4), CMV disease (7), viral hepatitis (7), and pneumonia (3) were important causes of morbidity. Two patients each had lymphoproliferative disease and new-onset diabetes. There were eight (17.8%) graft losses and six (14%) deaths. The one-, five- and 10-yr graft survivals were 91.1%, 80.4% and 75.1%, respectively; the mean graft survival was 119.4 ± 8.38 months. The respective patient survivals were 95.3%, 87.9%, and 76.9% at one-, five- and 10 yr. Our results affirm that despite scarcity of resources and frequent infections, long-term outcomes of pediatric renal transplantation are highly satisfactory.

Longitudinal relations between obesity and hypertension following pediatric renal transplantation

Obesity and hypertension frequently complicate renal transplantation (RTxp). The objective was to assess relations among obesity, hypertension, and glucocorticoids in pediatric RTxp recipients. A retrospective cohort study was carried out in 141 RTxp recipients, 2-21 years of age, with >or=12 months of follow-up. Body mass index Z-score (BMI-Z), systolic and diastolic blood pressure Z-scores (SBP-Z and DBP-Z), and medications at 1, 3, 6, and 12 months and annually thereafter were recorded. Quasi-least squares regression analysis was used. The prevalence of obesity (BMI>or=95th percentile) increased from 13% at baseline to >30% from 3 months onward. Greater glucocorticoid exposure (mg/kg/day) was associated with greater increases in BMI-Z (p<0.001). This association was greater in males, younger recipients, and those with lower baseline BMI-Z (all interactions p<0.02). The prevalence of systolic hypertension (SBP>or=95th percentile) was 73% at 1 month and >or=40% at all follow-up visits. Greater glucocorticoid exposure (p<0.001) and increases in BMI-Z (p=0.005) were independent determinants of SBP-Z over time. Cyclosporine (versus tacrolimus) was independently associated with greater SBP-Z and DBP-Z (p=0.001). Sustained obesity and hypertension frequently complicated pediatric RTxp. Obesity was an independent determinant of systolic hypertension. Strategies are needed to prevent obesity and its impact on hypertension, cardiovascular disease, and allograft survival.

Body size in children with chronic kidney disease after gastrostomy tube feeding

Outcome body size of gastrostomy tube (g-tube)-fed children with chronic kidney disease (CKD) was investigated. CKD patients, stages 2-5, who had a g-tube inserted and removed between 1985 and 2007 were retrospectively reviewed (n=20) for anthropometrics, lab values, and steroid use from insertion to latest date. CKD patients never having had a g-tube placed (n=82) acted as the comparison population with similar data collection at start and end of the latest 5-year period. Body mass index (BMI)-for-age, weight (Wt)-for-age, and height (Ht)-for-age z scores were calculated and compared between groups. Median age at insertion and duration of g-tube treatment was 1.7 years (range 0.9-15.6), and 2.9 years (range 0.9-11.8), respectively. There was a significant increase in Wt- (p<0.01), and BMI-for-age (p<0.03) z score, but not for Ht-for-age between insertion and removal for subjects. There were no significant differences in Ht-, Wt-, or BMI-for-age z scores, from removal to 5 years post-removal. In the comparison population, there were no significant differences in Ht-, Wt-, or BMI-for-age z scores over the 5-year period. Approximately 36% of the non-tube-fed comparison population and 50% of the tube-fed subjects were overweight or obese at the most recent evaluation. In both subjects and the comparison group, overweight and obesity is associated with transplant status and steroid use. G-tube feeding is an effective method for achieving catch-up weight and moderate height gain in pediatric CKD patients, and does not apparently predispose patients to obesity after removal; however, overweight and obesity may pose problems to children with CKD whether or not they are tube fed.

Early origins of cardiovascular disease in pediatric chronic kidney disease

The importance of cardiovascular disease in adults with chronic kidney disease is now well recognized. For children who develop chronic kidney disease, cardiovascular disease is also a leading cause of eventual morbidity and mortality. Although the clinical manifestations of cardiovascular disease may not be apparent until later, early subclinical findings can be observed even during childhood. This review updates the reader on the epidemiology of cardiovascular disease in pediatric chronic kidney disease, discusses risk factors and potential mechanisms of accelerated cardiovascular disease, reviews evidence of early manifestations of cardiovascular disease in pediatric chronic kidney disease, and briefly discusses prevention and treatment strategies.

Nonimmune complications after transplantation

As posttransplant longevity has increased, nonimmune complications related to the transplant and posttransplant course have emerged as important factors in defining long-term outcomes. The incidence of, and risk factors for these complications may vary by transplanted organ based on immunosuppressive protocols and preexisting risk factors. This article discusses the relevant nonimmune complications associated with posttransplant care, with a focus on risk factors and management strategies.

Post-transplant glucose status in 61 pediatric renal transplant recipients: preliminary results of five Turkish pediatric nephrology centers

To assess the incidence, risk factors and outcomes of PTDM, a total of 61 non-diabetic children (24 girls, 37 boys, age: 14.5 +/- 2.1 yr) were examined after their first kidney transplantation (37.3 +/- 21.6 months) with an OGTT. At baseline, 16 (26.2%) patients had IGT, 45 (73.8%) had NGT, and no patient had PTDM. No significant difference was shown between TAC- and CSA-treated patients in terms of IGT. Higher BMI z-scores (p = 0.011), LDL-cholesterol (p < 0.05) and triglyceride levels (p < 0.01), HOMA-IR (p = 0.013) and lower HOMA-%beta (p = 0.011) were significantly associated with IGT. Fifty-four patients were re-evaluated after six months; eight patients with baseline IGT (50%) improved to NGT, three (19%) developed PTDM requiring insulin therapy, five (31%) remained with IGT, and four patients progressed from NGT to either IGT (two) or PTDM (two). These 12 progressive patients had significantly higher total cholesterol (p < 0.05), triglycerides (p < 0.05), HOMA-IR (p < 0.01) and lower HOMA-%beta (p < 0.0) than non-progressive patients at baseline. We can conclude that post-transplantation glucose abnormalities are common in Turkish pediatric kidney recipients, and higher BMI z-scores and triglyceride concentrations are the main risk factors. Considering that the progressive patients are significantly more insulin resistant at baseline, we suggest that the utility of both HOMA-IR and HOMA-%beta in predicting future risk of PTDM and/or IGT should be evaluated in children.

Serum adiponectin levels and ambulatory blood pressure monitoring in pediatric renal transplant recipients

BACKGROUND.: Reduced levels of serum adiponectin, an adipokine, are associated with cardiovascular and obesity-related diseases; however, relations between adiponectin and hypertension are unclear. METHODS.: This cross-sectional study examined adiponectin and ambulatory blood pressure monitoring (ABPM) in 33 pediatric renal transplant recipients (TXP), aged 8 to 19 years, median of 1.9 years after transplant. Serum total adiponectin (microg/mL) and high molecular weight-to-total adiponectin ratio (HMWr), 24-hr ABPM, and dual x-ray absorptiometry measures of fat mass were obtained. RESULTS.: The 12 TXP with hypertension (defined as BP index >1.0 and BP load >25%) had lower total adiponectin levels (7.4+/-3.2 vs. 10.9+/-5.2 microg/mL, P=0.045) compared with nonhypertensive TXP. Hypertensive TXP trended toward lower HMWr compared with nonhypertensive TXP (0.40+/-0.09 vs. 0.47+/-0.11, P=0.064). Levels did not differ according to sex, obesity or dipper status. In univariate analyses, total adiponectin and HMWr were negatively and significantly correlated with indexed BP in the daytime, nighttime, and 24-hr periods (R=-0.35 to -0.57). After adjustment for estimated glomerular filtration rate, fat mass, anti-hypertensive medication and fasting glucose, (1) lower total adiponectin was significantly and independently associated with greater elevations in all ABPM indexes except for nighttime systolic indexed BP, and (2) HMWr was inversely associated with all ABPM indexes. Lower adiponectin levels (P=0.049) and HMWr (P=0.042) were associated with greater odds of hypertension. CONCLUSION.: These data indicate that lower total adiponectin and HMWr were significantly and independently associated with greater ambulatory blood pressure.

Cardiorespiratory fitness in pediatric renal transplant recipients

BACKGROUND

The impact of body size, fat-free mass (FFM), and fat mass (FM) on cardiorespiratory fitness in pediatric renal transplant recipients (TX) has not been established. Study objectives were to assess maximal oxygen consumption (VO2max) in TX and controls, adjusted for body composition, and to identify risk factors for reduced fitness in TX.

METHODS

Cycle ergometry and dual-energy X-ray absorptiometry were obtained in 50 TX and 70 controls, ages 8 to 21 years. Control recruitment was targeted to include obese subjects with body mass index Z-scores comparable with TX. Allometric regression models were used.

RESULTS

TX had significantly lower height Z-scores (P<0.001) and comparable body mass index Z-scores. VO2max per body weight (mL/kg/min) and per FFM (mL/kgFFM/min) did not differ between groups. However, VO2max was 13% lower (95% CI 18, 8; P<0.001) in TX, compared with controls, adjusted for FM, FFM, sex, and race. Greater FFM, lower FM, non-black race, and male sex were independently associated with greater VO2max. Within TX, hemoglobin levels were positively associated with VO2max (P=0.04) and sirolimus use was associated with lower VO2max (P<0.01).

CONCLUSIONS

TX had significant VO2max deficits that were not captured by conventional measures (mL/kg/min). Greater FM was an independent risk factor for low VO2max. Lower fitness in TX may be related to sirolimus effects on skeletal muscle.

Prevalence of metabolic syndrome and obesity in renal transplanted Mexican children

The purpose of the study was to evaluate the prevalence of MS and obesity in Mexican children with more than one yr post-renal transplantation. Thirty-two children transplanted between January 2004 and February 2006 were included in the study. The weight and height at the time of renal transplant were obtained. A fasting blood sample was drawn for serum creatinine, adiponectin, and complete lipid profile, and a three-h glucose tolerance test was also taken. A complete nutritional evaluation was performed including anthropometry. There was a statistically significant increase in BMI at one yr post-transplant that was maintained at two yr post-transplant. Three patients exhibited obesity and were overweight. Seventeen patients had hypertension, 14 patients had low HDL, 12 patients had hypertriglyceridemia, all had normal fasting glucose, six of them had glucose intolerance, and two had waist circumference higher than 90%. Eight patients (25%) had MS. Patients with MS had higher proportion of deceased donor grafts, acute rejection episodes, and received more methylprednisolone pulses; also they had a statistically significant higher pretransplant BMI than patients without MS. There was a significant relationship between BMI at one yr post-renal transplant and creatinine clearance estimated by Schwartz formula.

Cardiovascular disease in CKD in children: update on risk factors, risk assessment, and management

In young adults with onset of chronic kidney disease in childhood, cardiovascular disease is the most common cause of death. The likely reason for increased cardiovascular disease in these patients is a high prevalence of traditional and uremia-related cardiovascular disease risk factors during childhood chronic kidney disease. Early markers of cardiomyopathy, such as left ventricular hypertrophy and left ventricular dysfunction, and early markers of atherosclerosis, such as increased carotid artery intima-media thickness, carotid arterial wall stiffness, and coronary artery calcification, frequently are found in this patient population. The purpose of this review is to provide an update of recent advances in the understanding and management of cardiovascular disease risks in this population.

Effect of obesity on response to cardiovascular drugs in pediatric patients with renal disease

Obesity is associated with an increased concentration of inflammatory mediators, which in turn, in adults, reduces the response to calcium channel blockers (CCBs). We reviewed the medical charts of 263 pediatric nephrology patients with renal conditions, with the aim of studying the effect of obesity on the response to L-type CCBs, angiotensin interrupting agents (ANGIs), or a combination of the two. Forty-eight patients were ultimately enrolled in the study: 25 obese and 23 non-obese patients. The effect of the treatments on lowering the blood pressure was compared in obese versus non-obese patients. The systolic response to CCBs, measured as at least a 10% reduction from the baseline, was significantly lower in the obese (12.5%) patients than in the non-obese (52.9%) ones. The differences in diastolic response (58.8 and 25% for non-obese and obese patients, respectively) did not reach significance. The percentage response to CCBs, however, was significantly less in the obese patients than in the non-obese patients for both systolic and diastolic blood pressure. Corticosteroids also significantly influenced the response to CCBs in terms of diastolic pressure (62.9 and 25% for non-obese and obese patients, respectively). None of the tested covariates, including obesity, was found to significantly influence the response to ANGIs alone or in various combinations with CCBs. In conclusion, obesity and corticosteroid therapy should be considered when initiating antihypertensive drug treatment in children with kidney disease as both may contribute to a reduced efficacy of the antihypertensive therapy.

Long-term outcome after renal transplantation in childhood

The purpose of this article is to review: 1. Factors influencing long-term outcome data after transplantation 2. Patient survival overall, the effect of recipient age and donor type, causes of death, comparison of mortality after transplantation with that on dialysis, and effect of pre-emptive transplantation and race 3. Transplant survival overall, and the effect of recipient and donor age, donor type, pre-emptive transplantation, recurrent diseases, human leukocyte antigen (HLA) matching, immunosuppression, concordance, hypertension, bladder dynamics and type of donor nephrectomy 4. Final height and obesity 5. Psycho-social outcome.

Hypertension after renal transplantation

Hypertension is a common and serious complication after renal transplantation. It is an important risk factor for graft loss and morbidity and mortality of transplanted children. The etiology of posttransplant hypertension is multifactorial: native kidneys, immunosuppressive therapy, renal-graft artery stenosis, and chronic allograft nephropathy are the most common causes. Blood pressure (BP) in transplanted children should be measured not only by casual BP (CBP) measurement but also regularly by ambulatory BP monitoring (ABPM). The prevalence of posttransplant hypertension ranges between 60% and 90% depending on the method of BP measurement and definition. Left ventricular hypertrophy is a frequent type of end-organ damage in hypertensive children after transplantation (50-80%). All classes of antihypertensive drugs can be used in the treatment of posttransplant hypertension. Hypertension control in transplanted children is poor; only 20-50% of treated children reach normal BP. The reason for this poor control seems to be inadequate antihypertensive therapy, which can be improved by increasing the number of antihypertensive drugs. Improved hypertension control leads to improved long-term graft and patient survival in adults. In children, there is a great potential for antihypertensive treatment that could also result in improved graft and patient survival.

Cardiovascular complications of pediatric chronic kidney disease

Cardiovascular disease (CVD) mortality is a leading cause of death in adult chronic kidney disease (CKD), with exceptionally high rates in young adults, according to the Task Force on Cardiovascular Disease. Recent data indicate that cardiovascular complications are already present in children with CKD. This review summarizes the current literature on cardiac risk factors, mortality and morbidity in children with CKD.

Tracking of blood pressure and its impact on graft function in pediatric renal transplant patients

We studied tracking of BP and its impact on GFR in 44 PRTP followed for 56 months. Three months PT 77% had elevated SBP percentile. First year SBP and DBP correlated positively with final values (p < 0.0001, 0.0002, respectively). Pretransplant and three month PT SBP correlated positively (p = 0.02). At one yr, SBP and DBP were inversely associated with GFR (p = 0.002, p < 0.0001, respectively). SBP and BMI were positively associated at all time points. DBP was significantly higher in deceased recipients throughout the study period. Final DBP was higher (p = 0.03) and GFR lower (p = 0.04) in African-American patients. Patients with end-stage renal disease caused by glomerular disease had higher SBP (p = 0.03) and DBP (p = 0.04) than those with congenital malformations. GFR at one-yr PT (p = 0.02) and end of study (p = 0.003) was significantly lower in patients with high BP. Moreover, patients who maintained a normal systolic BP throughout the study had a significantly higher final GFR than those who were hypertensive at both time points [84 (normal BP throughout) vs. 52 mL/min/1.73 m(2) (high BP throughout), p = 0.02]. We conclude that PT hypertension is common in PRTP and predicts lower GFR.

Nutrition in children with CRF and on dialysis

The objectives of this study are: (1) to understand the importance of nutrition in normal growth; (2) to review the methods of assessing nutritional status; (3) to review the dietary requirements of normal children throughout childhood, including protein, energy, vitamins and minerals; (4) to review recommendations for the nutritional requirements of children with chronic renal failure (CRF) and on dialysis; (5) to review reports of spontaneous nutritional intake in children with CRF and on dialysis; (6) to review the epidemiology of nutritional disturbances in renal disease, including height, weight and body composition; (7) to review the pathological mechanisms underlying poor appetite, abnormal metabolic rate and endocrine disturbances in renal disease; (8) to review the evidence for the benefit of dietetic input, dietary supplementation, nasogastric and gastrostomy feeds and intradialytic nutrition; (9) to review the effect of dialysis adequacy on nutrition; (10) to review the effect of nutrition on outcome.

Noninvasive assessment of target organ injury in children with the metabolic syndrome

The prevalence of overweight has increased sharply since the 1980s, with morbid obesity rising at an even higher rate. Comorbidities related to adiposity now consume almost 10% of all US health care dollars. Unfortunately, overweight children already demonstrate elevations in cardiovascular risk factors. These children are extremely likely to remain obese in adulthood and are likely to progress to diabetes and heart and kidney diseases. It is not surprising, therefore, that the diagnosis of the metabolic syndrome is being made with increasing frequency in American adolescents. The authors show that noninvasive methods are now available to measure target organ damage related to obesity and the metabolic syndrome in children. They explore the data linking the cardiovascular risk factors that cluster as the metabolic syndrome to early subclinical atherosclerotic change such as left ventricular hypertrophy, carotid intima-media thickness, vascular function abnormalities, and microalbuminuria. Evidence for the benefits of treatment and guidelines for the assessment for target organ damage in children are provided.

Effect of Body Mass Index on Outcome in Pediatric Heart Transplant Patients

BACKGROUND

Obesity and cachexia are risk factors for adverse outcomes in adult transplant patients. However, little is known about the effects of body mass index (BMI) on outcomes in pediatric heart transplant patients.

METHODS

Patients > 2 years of age undergoing heart transplantation from 1985 to 2004 at our institution were included in this study. BMI was assessed at the time of transplant and at 1 year post-transplant. Long-term outcomes were assessed by weight group.

RESULTS

The cohort included 105 patients with a mean age at transplant of 9.6 +/- 5.3 years. The mean BMI percentile at the time of transplant was 39 +/- 34, with 22 (21%) patients underweight (< 5th percentile) and 8 (8%) patients overweight (> or = 95th percentile). Among patients surviving to 1 year (n = 92), the mean BMI percentile increased to 57 +/- 33 (p < 0.05). Overall graft survival was decreased in patients underweight at transplant, mean 6.7 years (95% confidence interval [CI] 3.6 to 9.9), vs normal weight patients, mean 10.6 years (95% CI 8.8 to 12.4) (p < 0.05). Patients overweight at transplant did not have decreased graft survival. Neither low nor high BMI at 1 year post-transplant was associated with adverse outcomes. On multivariate analysis, being underweight at transplant was an independent predictor of decreased graft survival (p = 0.03).

CONCLUSIONS

Weight gain was nearly universal post-transplant with only 4% of patients underweight at 1 year. In the small number of patients overweight at transplant, graft survival was similar to normal-weight patients. Conversely, being underweight at transplant was an independent predictor of decreased graft survival.

Selected Primary Care Issues and Comorbidities in Children Who Are on Maintenance Dialysis: A Review for the Pediatric Nephrologist

Ten-year survival of all children who initiate dialysis at any age now approaches 70%, and in the older child this number is closer to 80%. These children will live with chronic kidney disease and its myriad of associated comorbidities during and throughout their childhood. Their care is complex and requires both teamwork and careful attention paid to maintaining lines of communication among patient, family, and both the facility-based nephrology team and caregivers who are outside the hospital setting. Irrespective of their need for dialysis, children with ESRD deserve and require developmentally appropriate care and anticipatory guidance with respect to primary care issues of childhood. The child who is on dialysis often is cared for solely or in large part by a nephrology service, therefore this review discusses issues that are particularly important to pediatric nephrologists in relation to selected primary care issues and comorbidities for the child who is on dialysis, with an emphasis on medical and psychosocial issues, and with particular weight placed on issues that are pertinent to the adolescent dialysis patient.

Body mass index as a predictive factor for long-term renal transplant outcomes in Asians

BACKGROUND

There is substantial evidence that renal transplant recipients with obesity or body mass index >30 kg/m(2) have increased risk of graft loss. However, few data exist for Asian population; clinicians have to rely upon indirect evidence by extrapolating the results from Caucasians to Asian recipients.

STUDY

Using data from a study population of 150 consecutive cadaveric or living related Chinese renal transplant recipients at our center between 1985 and 2002, we examined the effect of baseline body mass index cut-off 25 kg/m(2) on the transplant outcomes using Kaplan-Meier analysis and Cox proportional hazards analysis. Primary study end point was overall graft survival.

RESULTS

The mean body mass index was 22.9 +/- 4.0 kg/m(2). Thirty-seven (25%) patients were classified as overweight and 113 patients as non-overweight, using the cut-off of 25 kg/m(2). After median follow up period of nine yr, 15 graft losses (41%) occurred in the overweight group, as compared with 14 graft losses (12%) in the non-overweight group. Kaplan-Meier estimates of cumulative graft survival at five yr were significantly worse for the overweight group than non-overweight group (83.6% versus 92.7%, p = 0.0041). By multivariate Cox proportional hazards analysis, baseline body mass index > or =25 kg/m(2) conferred a significantly higher risk of graft loss (with relative risk of 4.78, 95% CI = 1.52-15.2) and doubling of serum creatinine (relative risk 3.19, 95% CI = 1.22-8.40). Death with a functioning graft occurred in 11% of overweight recipients, compared with 3% among the non-overweight group (p = 0.041).

CONCLUSION

Our results draw attention to a recipient body mass index cut-off value > or =25 kg/m(2), which might confer an increased risk of graft loss in Asian kidney transplant populations.

Left ventricular hypertrophy in pediatric kidney transplant recipients: long-term follow-up study

Cross-sectional studies indicate that LVH, known cardiovascular risk factor, is frequent in pediatric patients post-kidney transplant. We performed a retrospective longitudinal analysis of echocardiographic data collected in children and adolescents who received kidney transplant from 1998 to 2003. The first echo was performed at a median time post-transplant of 14 months in 47 children; a second echo (echo 2) was carried out at a median time of 33 months in 31 and a third echo (echo 3) was performed at a median time of 49 months in 14 children. LVH was defined as LV mass index >/=95th percentile for children. LVH was present in echo 1 in 25 (54%) subjects. Systolic blood pressure (p = 0.02) and BMI (p = 0.02) independently predicted the LVH seen in echo1 in multivariate logistic regression. In 14 subjects with three consecutive echocardiograms LVM index significantly decreased from echo 1 to echo 2 and from echo 1 to echo3 (p < 0.05), but no significant changes were observed between echo 2 and echo 3. The overall prevalence of LVH remained unchanged but its severity significantly decreased during the follow-up. The results of the study suggest that despite regression of LVM index overtime-pediatric patients post-kidney transplant are at continuous risk for developing cardiovascular disease.

Obstructive Sleep Apnea-Hypopnea Syndrome in Children Is Not Associated With Obesity

OBJECTIVE

The prevalence of obstructive sleep apnea-hypopnea syndrome (OSAHS) in the general pediatric population ranges from 1% to 3%. However, its prevalence in an unselected population of obese children is unknown. We studied the association between obesity and OSAHS in children diagnosed with the syndrome in a cohort of boys and girls (age range, 2-14 years) referred to the pediatric respiratory medicine outpatient clinic at our hospital for suspected apnea, snoring, or both over the past 5 years.

PATIENTS AND METHODS

The medical history of each patient was recorded and all patients underwent a physical examination, chest and nasal cavities radiography, and 8-channel respiratory polygraphy during sleep. The following variables were evaluated: sex, reason for consultation, source of referral, findings during upper airway examination, age, weight z-score (reflecting how much a finding differs from the mean and in what direction in a normally distributed sample), height z-score, body mass index (BMI) z-score, number of apneas, number of hypopneas, apnea index, hypopnea index, apnea-hypopnea index (AHI), oxygen saturation (mean and minimum) measured by pulse oximetry, number of snores, and snore index.

RESULTS

Of the 400 patients studied, 242 (60.5%) were male and 158 (39.5%) female. The mean age was 4.95 years. OSAHS (AHI> or =3) was diagnosed in 298 cases (74.5%) and these patients were then studied to determine the relation between OSAHS and obesity. The anthropometric distribution (expressed as mean [SD]) was as follows: weight z-score, 0.37 (1.31); height z-score, 0.23 (1.19); BMI, 17.063 kg/m(2) (2.51); and BMI z-score, 0.39 (1.36). The respiratory polygraph during sleep recorded an AHI of 6.56 (7.56).

CONCLUSIONS

No differences were observed between the height z-score, weight z-score, BMI z-score, age, and AHI. No association between obesity and OSAHS was found in this series. However, studies of larger, unselected populations are needed to determine if obesity is a risk factor for OSAHS in children.

The role of obesity and its bioclinical correlates in the progression of chronic kidney disease

In spite of a progressive fall in the incidence of traditional risk factors of cardiovascular morbidity (cigarette smoking, high blood pressure, and hyperlipidemia), there is an upward trend in the prevalence of obesity and chronic kidney disease (CKD). Furthermore, there is a strong correlation between body mass indices and the relative risk of progression of CKD. The close biophysiological interaction between obesity and CKD is evident by a similar occurrence of comorbidities including insulin resistance, hyperlipidermia, endothelial dysfunction, and sleep disorders. Truncal obesity is a primary component of metabolic syndrome; unlike peripheral fat, the visceral adipocytes are more resistant to insulin. In addition, lipolysis results in a release of free fatty acid and TG, whereas hypertriglycedemia is potentiated by uremic activation of fatty acid synthase. Hypertriglycedemia and low HDL cholesterol increase the relative risk of progression of CKD. Furthermore, endothelial inflammation and premature atherosclerosis are promoted by hyperhomocysteinemia and oxidation of LDL, both of which are commonly observed in CKD and obesity. Predominance of oxidative stress in both obesity and azotemia stimulate synthesis of angiotensin II, which in turn increases TGF-B and plasminogen activator inhibitor-1, thereby propagating glomerular fibrosis. Furthermore, local synthesis of angiotensinogen by adipocytes, leptin activation of sympathetic nervous system, and hyperinsulinemia contribute to the development of hypertension in obesity and CKD. In addition, increased renal tubular expression of Na-K-ATPase and a blunted response to natiuretic hormones in obesity promote salt and water retention. Glomerular hyperfiltration from systemic volume load and hypertension results in mesangial cellular proliferation and progressive renal fibrosis. In addition, maternal nutritional deprivation increases the incidence of obesity, hypertension, and diabetes in adulthood. Reduced fetal protein synthesis contributes to oxidative glomerular injury and impairment of renal morphogenesis. Thus, kidneys are poorly equipped to handle physiologic stress that may result from the rapid body growth and programmed metabolic dysfunction later in life. Finally, in order to minimize morbidity of obesity-related kidney disease, preventive strategy must include optimal maternal health care, promotion of healthy nutrition and routine physical exercise, and early detection of CKD.

Epidemic of childhood obesity: implications for kidney disease

Childhood obesity has become a global epidemic. Childhood obesity has many long-term adverse effects on morbidity and mortality. The prevalence of end-stage renal disease (ESRD) has risen dramatically in the past decade in parallel with the increase in obesity. Our current understanding of the consequences of childhood obesity on kidney function and disease is very limited. The present study presents the worldwide trends in childhood obesity and reviews published studies that have examined the association between obesity and kidney disease in the pediatric and adult populations. A large number of studies have been conducted to examine the association between obesity and kidney disease in general adult populations; however, few have been conducted to examine the impact of childhood obesity on the risk of kidney disease. Findings from large cohort studies in adult general populations show that obesity increases the risk of kidney diseases. Six follow-up studies in pediatric patients were identified, and they indicate that childhood obesity is associated with an increased risk of kidney disease and the progression and mortality of kidney disease. Future studies in the pediatric populations are needed.

Effect of obesity and overweight on cyclosporine blood levels and renal functions in renal adolescent recipients

INTRODUCTION

The impact of obesity, a frequent problem after renal transplantation, which has been associated with poor graft and patient survival, was evaluated on renal function and cyclosporine (CsA) blood levels.

PATIENTS

We retrospectively evaluated the data of adolescent renal recipients between 1994 and 2004. Patients with serum creatinine > or = 2.5 mg/dL were excluded. We grouped the data with regard to the body mass index (BMI) percentiles as group I (BMI > 95th), group II (BMI < 95th), group III (BMI > 85th), group IV (BMI < 85th). We compared the clinical and laboratory findings between groups I and II and between groups III and IV.

RESULTS

We evaluated 778 visits of 27 patients (M/F: 19/8). There were 30 visits in the obesity period (group I) and 72 visits after the overweight periods were added (group III). Serum creatinine levels were significantly higher and glomerular filtration rate levels significantly lower among obese and/or overweight than lean periods (P < .05). Proteinuria levels were similar in groups I and II, but significantly higher in group III than group IV (P = .356 and .000, respectively). CsA(mg/bw), CsA(mg/bmi), and CsA(mg/bsa) levels were significantly lower in group I than group II and in group III than group IV (P < .05), while C0 and C2 levels were similar (P > .05).

CONCLUSION

Weight gain is associated with worse renal functions but not greater proteinuria in our patients. Smaller CsA doses were sufficient to maintain C0 and C2 levels similar to the lean patients, results that were parallel to those of adult renal recipients.

Nondiabetic consequences of obesity on kidney

There has been a major increase in obesity among children over the past twenty years. Obesity is associated with glomerular hyperperfusion and hyperfiltration from physiological (mal)adaptation resulting from afferent arteriolar vasodilatation. The renal injury from hyperfiltration in obesity is further exacerbated by concomitant presence of dyslipidemia, hyperglycemia and/or insulin resistance, inflammation and hypertension. The renal injury clinically manifests as microalbuminuria, proteinuria and/or poor renal function, and is histologically characterized by glomerulomegaly, mesangial expansion and/or sclerosis, which has been termed "obesity related glomerulopathy". Obesity portends a poor prognosis in subjects with chronic kidney diseases, IgA nephropathy and nephrectomy. Obese individuals on dialysis and renal transplant have mixed outcomes. The purpose of this review is to highlight the nondiabetic consequences of obesity on kidney for the pediatric nephrology community as we begin to address the obesity epidemic in children.

Pediatric obesity at renal transplantation: a single center experience

Obesity is a major issue affecting health care delivery. While studies have been done in adults with end-stage renal disease, similar studies are lacking in pediatric patients with this disease. We retrospectively analyzed our renal transplant database from 1978 to 2002, to identify prevalence and predisposing factors to obesity in a pediatric end-stage renal disease population. Obesity, particularly in younger individuals, was found to be prevalent at transplantation.

Managing the Failing Allograft

Managing the failing allograft juxtaposes immunosuppressive management and routine chronic kidney disease care. The complications of immunosuppression can be more pronounced in those with renal failure (infection, anemia, bone disease). The withdrawal of immunosuppression may be associated with acute allograft rejection, arthralgias, and the development of antidonor antibodies. Likewise depression is prevalent. Improving well-being and overall survival necessitates proper titration of immunosuppressive medications and control of blood pressure, anemia, lipids, and glucose along with attention to treatment of depression.