II. Pediatric guidelines

Nutrition in Children with Kidney Disease: Pitfalls of Popular Assessment Methods

Children with chronic kidney disease (CKD) are considered at high risk for protein-energy malnutrition. Clinical practice guidelines generally recommend an evaluation of numerous nutritional parameters to give a complete and accurate picture of nutritional status. This review summarizes the potential limitations of commonly used methods of nutritional assessment in the setting of CKD. Unrecognized fluid overload and inappropriate normalization of body composition measures are the most important factors leading to misinterpretation of the nutritional assessment in CKD. The importance of expressing body composition measures relative to height or height-age in a population in whom short stature and pubertal delay are highly prevalent is emphasized. The limitations of growth as a marker for nutritional status are also addressed. In addition, the prevailing belief that children with CKD are at high risk for malnutrition is challenged.

Evaluation of Nutritional Status and Factors Related to Malnutrition in Children on CAPD

Objective

The aim of this study was to investigate the nutritional status of children on continuous ambulatory peritoneal dialysis (CAPD) and to relate it to the dose of dialysis and serum levels of inflammatory cytokines and insulin-like growth factor-1 (IGF-1).

Patients

17 CAPD patients (8 girls, 9 boys; mean age 13.1 ± 3.5 years, median 15 years) were included in the study. Anthropometric measurements and serum albumin levels were used in the evaluation of nutritional status. Serum interleukin (IL)-1β, IL-6, tumor necrosis factor α, and IGF-1 levels were determined in all CAPD patients and in a healthy control group. Weekly Kt/V and creatinine clearance (CCr) were measured to determine adequacy of dialysis.

Results

The mean dialysis period was 23.7 ± 15.2 months (median 23 months). Anthropometric measurements and serum albumin level were as follows: height 130.2 ± 15.6 cm, height standard deviation score (HtSDS) -4.2 ± 2.4, body mass index (BMI) 16.3 ± 1.6 kg/m2, body mass index standard deviation score (BMISDS) -0.8 ± 0.9, triceps skinfold thickness (TST) 4.2 ± 1.4 mm, midarm circumference (MAC) 16.21 ± 2.3 cm, upper arm muscle area (AMA) 1799.1 ± 535.7 mm2, upper arm fat area (AFA) 334.5 ± 143 mm2, and serum albumin 3.1 ± 0.7 g/dL. The BMI was above the fifth percentile in all patients; TST and MAC were below the fifth percentile in 14 patients (82.4%) and 10 patients (58.8%) respectively. The AMA was below the fifth percentile in 8 patients; however, the AFA was below the fifth percentile in all patients. Mean serum albumin level was under 3.5 g/dL in 70.5% of the children. We found significant positive correlations between BMI and Kt/V ( r = 0.69, p < 0.01), CCr ( r = 0.64, p < 0.05), and IL-6 ( r = 0.61, p < 0.01). There was an inverse correlation between BMISDS and dialysis period ( r = -0.58, p < 0.05); and between IL-6 and serum albumin ( r = -0.49, p < 0.05). A significant positive correlation between BMISDS and serum IGF-1 level ( r = 0.62, p < 0.01) was noted. We also found a significant positive correlation between serum IGF-1 level and both HtSDS ( r = 0.57, p < 0.05) and TST ( r = 0.52, p < 0.05). Significant positive correlations between AFA and CCr and IGF-1 were also noted (both r = 0.56, p < 0.05).

Conclusion

Although many factors may be responsible for malnutrition and growth retardation, we found that prolonged period of dialysis, inadequate dialysis, and low IGF-1 levels are the most important risk factors in CAPD patients.

Pilot validation of objective malnutrition-inflammation scores in pediatric and adolescent cohort on chronic maintenance dialysis

Background:

In recognition of the challenges inherent with the use of single-item indices for the diagnosis of malnutrition–inflammation morbidity in pediatric dialysis patients, to enhance accuracy, we validated a composite scoring system in a pilot study. The objective malnutrition—inflammation score seeks to validate the use of a composite scoring system as a tool for assessing malnutrition—inflammation burden in a pediatric dialysis population.

Methods:

We enrolled 20 patients on hemodialysis (n = 14) and peritoneal dialysis (n = 6) over a period of 12 months. We derived composite scores from selected indices of renal pathology, nutrition, dialysis adequacy, protein catabolism, and dialysis modality. We assessed reliability by a test–retest method and measured validity by defining the relationship of the indices with serum C-reactive protein in a multiple regression analysis. We calculated sensitivity, specificity, accuracy, and precision for the malnutrition—inflammation score.

Results:

The mean age was 12.8 years (standard deviation = 6.1), and male–female ratio was 12:8. Patients (n = 8) with elevated serum C-reactive protein (>0.3 mg/dL) had higher composite score for malnutrition—inflammation morbidity. Similarly, the pediatric cohort on hemodialysis had higher score than those on peritoneal dialysis. Upon reliability testing, a low value of typical error (0.07) and high correlation coefficient (r = 0.95) supported validity of the instrument. Moreover, multiple regression analysis showed a strong predictive relationship (R² = 0.9, p = 0.03) between the indices and serum C-reactive protein. Sensitivity of malnutrition—inflammation score was 62.5%, specificity was 83%, accuracy was 75%, and precision was 71%.

Conclusion:

Using criterion-validation method, we established the potential use of multi-diagnostic approach to quantify malnutrition—inflammation morbidity in a pediatric dialysis cohort. Given the small sample size, large-scale population-specific studies are needed to ratify these findings and to demonstrate its clinical effectiveness.