Nutritional Status of Children with ESRD Varies with Renal Replacement Therapy Modality

Among pediatric patients with end-stage kidney disease (ESRD), the frequency of protein-energy malnutrition ranges from 20% to 80%, resulting in loss of lean mass, depletion of fat mass, and deceleration of growth, affecting height. Multiple factors are involved in these alterations, including hormonal imbalance, low nutrient intake, decreased residual renal function, use of renal replacement therapies (RRT), i.e., hemodialysis and peritoneal dialysis, chronic inflammation, and metabolic acidosis. Children who undergo kidney transplantation are often overweight or obese, creating a significant health problem, leading to graft rejection and increased morbidity and mortality.

There is no gold standard to compare the nutritional status of children with ESRD among cohorts of different models of RRT: hemodialysis, peritoneal dialysis, and kidney transplantation. There are few available data on assessment of nutritional status using anthropometric indicators in children with ESRD and on the possible factors involved in variations of the indicators in patients receiving different models of RRT. Julieta García De Alba Verduzco, BSC, MSC, and colleagues conducted an analytical cross-sectional study of consecutive cases from the nephrology service of the Pediatric Hospital of the Western National Medical Center of the Mexican Institute of Social Security to demonstrate that there are differences in the factors associated with anthropometric indicators of nutritional status, with particular emphasis on arm indicators, in children with ESRD undergoing peritoneal dialysis, hemodialysis, and after kidney transplantation. Results of the study were reported in the Journal of Renal Nutrition [2018;28(5):352-358].

The study cohort included 130 children and adolescents, aged 6 to 18 years with ESRD who were undergoing RRT: 37% (n=49) underwent kidney transplantation, 26% (n=33) were undergoing peritoneal dialysis, and 36% (n=48) were undergoing hemodialysis. Measurements of weight, height, mid-upper arm circumference (MUAC), tricipital skinfold (TSF), and subscapular skinfold (SSF) were performed. With MUAC and TSF, total arm area (TAA), arm muscle area (AMA), and arm fat area (AFA) were calculated. Body mass index (BMI) was also obtained.

Of the 130 study participants, 48% (n=63) were female (23 underwent transplantation, 24 were undergoing hemodialysis, and 16 were undergoing peritoneal dialysis). Of the 67 male participants, 26 underwent kidney transplantation, 24 were undergoing hemodialysis, and 17 were undergoing peritoneal dialysis. Mean age was 13.1 years for the kidney transplant patients, 13.5 years for those undergoing hemodialysis, and 12.8 for those undergoing peritoneal dialysis. There were no differences by age and sex among the study groups.

The marital status of the parents of the participants was classified into two groups: (1) parents who had a partner and (2) parents who did not cohabit with a partner. The frequency of parents living as a couple was higher among participants who underwent kidney transplantation compared with those undergoing hemodialysis (odds ratio [OR], 3.5, 95% confidence interval [CI], 1.34-9.0); P=.009). In comparisons of patients undergoing peritoneal dialysis versus hemodialysis, findings were similar (OR, 3.0; 95% CI, 1.06-8.8; P=.036).

Ninety percent of the parents of the three groups were employed; the frequency of mothers working outside the home was significantly higher for patients who underwent kidney transplantation than for those undergoing hemodialysis (OR, 13.7; 95% CI, 4.56-41.05; P<.001) or peritoneal dialysis (OR, 15.4; 95% CI, 4.8-49; P<.001). Household income for the three groups was $388 (US) per month for patients in the kidney transplantation group, $304 (US) per month for patients in the hemodialysis group, and $373 (US) per month for those in the peritoneal group.

More than 40% of all patients had a height/age z-score of less than –2 standard deviations (SD). Body mass index indicated that among patients in the hemodialysis and peritoneal dialysis groups, more than 40% had a z-score of less than –1 SD, as an expression of mild acute malnutrition; 36.7% of patients in the kidney transplant group were overweight or obese. There was a significant difference observed when comparing the BMI between hemodialysis versus kidney transplant and peritoneal dialysis versus kidney transplant in the category of ≤ –2 SD.

The MUAC in the hemodialysis and peritoneal dialysis groups was affected by more than 45%; 12% of the patients in the kidney transplantation group presented ≥ +1 SD z-score. There was no difference among the three groups in comparison of MUAC categories. There was a deficit in TSF in >30% of patients in the hemodialysis and peritoneal groups; the deficit was significantly higher in those groups than in patients who underwent kidney transplantation. The SSF was affected in 9% to 10% of patients in the two dialysis groups.

More than 10% of patients in the kidney transplant group had ≥ +2 SD z-score in TSF and SSF. More than 30% of the patients in the hemodialysis and peritoneal dialysis groups had a TAA deficit greater than < 1 SD; more than 50% of patients in the kidney transplant group had ≥ +2 SD z-score. This indicator was significantly higher in the transplant group compared with the other two groups.

In measurements of energy reserve as represented by the AFA, more than 35% of patients in the two dialysis groups had z-scores <–1 > –2 SD; 30% of patients in the kidney transplant group had ≥ + 1 SD z-score. AFA in patients in the kidney transplant group was significantly higher than in patients undergoing hemodialysis or peritoneal dialysis.  More than 50% of patients in each of the three groups showed that the indicator AMA (lean mass) was affected with < –1 SD z-score.

There were some limitations cited by the authors, including the lower number of children in the peritoneal dialysis group than in the other two groups.

“It is essential to carry out a complete and adequate anthropometric evaluation of the nutritional status of patients in each renal replacement therapy. The purpose is to identify and treat those patients with high risk of acute or chronic malnutrition, to prevent major morbidity that allows performing kidney transplantation in better clinical conditions. After kidney transplantation, the nutritional assessment is important to detect the probability of obesity that may also eventually affect the prognosis and quality of life in the long term,” the researchers said.

Takeaway Points

  1. Researchers in Mexico conducted an analytical cross-sectional study designed to examine the differences in factors associated with anthropometric indicators of nutritional status in pediatric end-stage renal disease patients undergoing hemodialysis, peritoneal dialysis, or after kidney transplantation.
  2. The number of parents living as couples was higher in the transplantation group than in the two dialysis groups; the number of patients with a mother working outside the home was higher for patients in the transplant and peritoneal dialysis groups than in the group undergoing hemodialysis.
  3. More than 40% of patients in all three groups had growth impairment; children in the transplant group were up to 9 times more likely to be overweight or obese.