Paediatric obesity and renal transplantation: current challenges and solutions

Growth after pediatric kidney transplantation: a 25-year study in a pediatric kidney transplant center

OBJECTIVES

Growth failure is one of the major complications of pediatric chronic kidney disease. Even after a kidney transplant (KT), up to 50 % of patients fail to achieve the expected final height. This study aimed to assess longitudinal growth after KT and identify factors influencing it.

METHODS

A retrospective observational study was performed. We reviewed the clinical records of all patients who underwent KT for 25 years in a single center (n=149) and performed telephone interviews. Height-for-age and body mass index (BMI)-for-age were examined at KT, 3 months, 6 months, 1 year, and 5 years post-transplant and at the transition to adult care. We evaluated target height, disease duration before KT, need and type of dialysis, recombinant human growth hormone pretransplant use, nutritional support, glomerular filtration rate (GFR), and cumulative corticosteroid dose.

RESULTS

At transplant, the average height z-score was -1.38, and height z-scores showed catch-up growth at 6 months (z-score -1.26, p=0.006), 1 year (z-score -1.15, p<0.001), 5 years after KT (z-score -1.08, p<0.001), and on transition to adult care (z-score -1.22, p=0.012). Regarding BMI z-scores, a significant increase was also detected at all time points (p<0.001). After KT, GFR was significantly associated with height z-score (p=0.006) and BMI z-score (p=0.006). The height in transition to adult care was -1.28 SD compared to the target height.

CONCLUSIONS

Despite the encouraging results regarding catch-up growth after KT in this cohort, results remain far from optimum, with a lower-than-expected height at the time of transition.

Malnutrition, sarcopenia, and frailty assessment in pediatric transplantation

Nutrition assessment can be challenging in children with end-stage organ disease and in those requiring an organ transplant. The effect of poor nutrition status can exert long-lasting effects on children with end-stage organ disease requiring transplantation. Malnutrition, sarcopenia, and frailty are conditions that require provision of optimal nutrition to prevent or support the treatment of these conditions. Unfortunately, the literature on the assessment of malnutrition, sarcopenia, and frailty in pediatric end-stage organ disease is scarce, thus leading to confusion on how to effectively identify them. Recently, the addition of a variety of validated nutrition and functional assessment techniques has assisted with appropriate assessment of these conditions. The objective of this narrative review is to provide an overview of the current literature for pediatric assessment of malnutrition, sarcopenia, and frailty in the setting of solid organ transplantation and provide practicing nutrition clinicians a solid foundation for learning how to effectively assess these conditions with the current literature available.

Associations of longitudinal height and weight with clinical outcomes in pediatric kidney replacement therapy: results from the ESPN/ERA Registry

BACKGROUND

Associations between anthropometric measures and patient outcomes in children are inconsistent and mainly based on data at kidney replacement therapy (KRT) initiation. We studied associations of height and body mass index (BMI) with access to kidney transplantation, graft failure, and death during childhood KRT.

METHODS

We included patients < 20 years starting KRT in 33 European countries from 1995-2019 with height and weight data recorded to the ESPN/ERA Registry. We defined short stature as height standard deviation scores (SDS) < -1.88 and tall stature as height SDS > 1.88. Underweight, overweight and obesity were calculated using age and sex-specific BMI for height-age criteria. Associations with outcomes were assessed using multivariable Cox models with time-dependent covariates.

RESULTS

We included 11,873 patients. Likelihood of transplantation was lower for short (aHR: 0.82, 95% CI: 0.78-0.86), tall (aHR: 0.65, 95% CI: 0.56-0.75), and underweight patients (aHR: 0.79, 95%CI: 0.71-0.87). Compared with normal height, patients with short and tall statures showed higher graft failure risk. All-cause mortality risk was higher in short (aHR: 2.30, 95% CI: 1.92-2.74), but not in tall stature. Underweight (aHR: 1.76, 95% CI: 1.38-2.23) and obese (aHR: 1.49, 95% CI: 1.11-1.99) patients showed higher all-cause mortality risk than normal weight subjects.

CONCLUSIONS

Short and tall stature and being underweight were associated with a lower likelihood of receiving a kidney allograft. Mortality risk was higher among pediatric KRT patients with a short stature or those being underweight or obese. Our results highlight the need for careful nutritional management and multidisciplinary approach for these patients. A higher resolution version of the Graphical abstract is available as Supplementary information.

Obesity in Kidney Transplantation: Impact on Transplant Candidates, Recipients, and Donors

Obesity is now common among children and adults who are kidney transplant candidates and recipients. It is associated with an increased risk of cardiovascular disease and kidney failure. This also pertains to potential living kidney donors with obesity. Obese patients with end-stage renal disease benefit from transplantation as do nonobese patients, but obesity is also associated with more risk. A complicating factor is that obesity is also associated with increased survival on maintenance dialysis in adults, but not in children. The assessment of obesity and body habitus should be individualized. Body mass index is a common but imperfect indicator of obesity. The medical management of obesity in renal failure patients is often unsuccessful. Bariatric surgery, specifically laparoscopic sleeve gastrectomy, can result in significant weight loss with reduced morbidity, but many patients do not agree to undergo this treatment. The best approach to manage obese transplant candidates and recipients is yet unresolved.

Long-Term Outcomes of Kidney Transplantation in Children

Kidney transplantation is the preferred treatment for end-stage renal disease (ESRD) in children and confers improved survival, skeletal growth, heath-related quality of life, and neuropsychological development compared with dialysis. Kidney transplantation in children with ESRD results in 10-year patient survival exceeding 90%. Therefore, the long-term management of these patients is focused on maintaining quality of life and minimizing long-term side effects of immunosuppression. Optimal management of pediatric kidney transplant recipients includes preventing rejection and infection, identifying and reducing the cardiovascular and metabolic effects of long-term immunosuppressive therapy, supporting normal growth and development, and managing a smooth transition into adulthood.

Age- and weight-based differences in haemodialysis prescription and delivery in children, adolescents and young adults

Background

Limited systematic data are available on prescription and dosing of haemodialysis (HD) in children and adolescents compared with adults. We aimed to characterize age- and weight-based differences in HD delivery in children, adolescents and young adults.

Methods

This is a retrospective observational study including 1852 patients <30 years on chronic HD from childhood (53 903 HD sessions), receiving thrice weekly outpatient HD between 2004 and 2016 in the USA (6075 patient-years, of which 2535 were in patients aged 1-18 years; weight range 8.3-168 kg). Median individual prescriptions per year were calculated and overall 50% (IQR) and 90% distribution ranges over age and weight were derived. Repeated measurements analysis of variance assessed differences between age and weight groups.

Results

Prescriptions significantly differed among age and weight groups (P < 0.001). Lower weight patients (<75 kg) had higher (inter-quartile range, IQR) weight-normalized blood flow rate (highest in <25 kg: QB/kg = 6.5-9.1 mL/min/kg), urea dialytic clearance (KD/kg) and single pool Kt/V (spKt/V) (<25 kg: 1.43-1.78; 25-50 kg: 1.52-1.92; 50-75 kg: 1.43-1.74) than heavier patients (lowest in >100 kg: QB/kg = 3.1-4.0 mL/min/kg, spKt/V = 1.22-1.47, respectively). Adolescents had significantly lower QB/kg, KD/kg and spKt/V (1.34-1.71) compared with adults (1.45-1.79) and children <12 years (range of 25th percentiles: 1.37-1.44). Dialytic clearance derived from a mechanistic equation underpredicted KD in children but not in young adults. Significant growth retardation was observed, with the proportion of patients <3rd percentile (height for age) decreasing from 71% (1-2 years) to 15% (>18 years).

Conclusion

Delivered HD treatment varies with age and weight and is more intensified in children aged <12 years, compared with adolescents and overweight young adults, who appear to be at highest risk of receiving suboptimal treatment. Still, delivery of target or higher spKt/V values did not result in appropriate growth in these children, questioning the value of spKt/V as a measure of HD adequacy in children. Provided ranges of outpatient HD prescription can help clinicians and researchers in personalizing and optimizing delivery of dialysis treatment.