Assessment of the Diagnostic Performance of MUAC in Malnutrition Screening and Its Correlation with Other Anthropometric Indicators in Healthy Children and Adolescents

BACKGROUND/OBJECTIVES

This study aimed to evaluate the correlation of mid-upper arm circumference (MUAC) z-scores with body mass index (BMI) and weight-for-height (WFH) z-scores to determine its reliability in identifying malnutrition and its potential in clinical practice in healthy children and adolescents.

METHODS

Our study included 906 healthy children and adolescents aged between 2 months and 18 years who were admitted to University Hospital's General Pediatrics Clinic and attended 12 primary schools in 6 additional Izmir provinces. Anthropometric measurements (weight, length/standing height, MUAC, BMI, WFH) were performed. The relationship between MUAC z-scores, BMI, and WFH z-scores of cases with malnutrition were evaluated.

RESULTS

According to the WHO BMI z-score classification, 6 (0.7%) of the children were defined as having severe undernutrition, 43 (4.7%) as moderate undernutrition, 146 (16.1%) as mild undernutrition, 486 (53.6%) as normal, 142 (15.7%) as overweight, and 83 (9.2%) as obese. At any age over two years, fair agreement was observed between MUAC z-scores and WHO BMI z-scores in defining malnutrition alone compared to other growth measures (weighted kappa = 0.371). Under two years of age, the correlation between MUAC z-scores and BMI z-scores showed moderate agreement in detecting overweight and obesity (weighted kappa = 0.479), and between MUAC and WHO WFH z-scores showed moderate agreement (kappa = 0.252).

CONCLUSIONS

The study found a moderate and fair connection between MUAC z-scores and other criteria. However, further MUAC z-score screening and diagnostic power testing in larger pediatric populations are needed to validate its use alongside other key anthropometric indicators in malnutrition diagnosis. MUAC measurement should be popularized in routine pediatric outpatient clinics to detect malnutrition quickly.

Phase Angle as a Risk Factor for Mortality in Patients Undergoing Peritoneal Dialysis

Phase angle (PhA) is measured using bioimpedance analysis and calculated using body reactance and resistance in the waveform at 50 kHz. Further studies are necessary to clarify the predictive efficacy of PhA in the mortality of peritoneal dialysis (PD) patients. The objective of this study was to assess the utility of PhA for predicting patient mortality and technique failure and compare the predictability of PhA with other risk factors. Our study had a retrospective cohort design. Our center routinely evaluates bioimpedance measurements for all prevalent PD patients (n = 199). The PhA was measured using multifrequency bioimpedance analysis. Our study evaluated patient and technique survival. There were 66, 68, and 65 patients in the low, middle, and high tertiles of PhA, respectively. The PhA values of the low, middle, and high tertiles were 3.6° (3.4-3.9), 4.4° (4.2-4.7), and 5.5° (5.2-6.0), respectively. The 5-year patient survival rates for the high, middle, and low tertiles were 100%, 81.7%, 69.9%, respectively (p < 0.001). The 5 year technique survival rates for the high, middle, and low tertiles were 91.9%, 74.8%, 63.7%, respectively (p = 0.004). Patient and technique survival increased as the PhA tertiles increased. Both univariate and multivariate Cox regression analyses demonstrated a consistent pattern. The prediction of patient or technique survival was better in PhA than in the other classical indicators. The present study demonstrated that PhA may be an effective indicator for predicting patient or technique survival in PD patients. Furthermore, it suggests that routine measurement of PhA and pre-emptive intervention to recover PhA according to causes of low PhA may help improve patient or technique survival in PD patients.

Association between phase angle and the nutritional status in pediatric populations: a systematic review

Background and aims

Malnutrition is prevalent in pediatric populations with any disease, and it is also related to changes in body composition. In addition, recent studies have documented relationships between these changes and phase angle (PhA), an important parameter of functional nutritional assessment. PhA could be a new marker of nutritional status. Many studies have generated information about the association between PhA and malnutrition in various pathologies, although the vast majority of this information is from adult populations. In this systematic review, we answered the following question: What is the association between PhA and the nutritional status in pediatric populations?

Methods

We performed a systematic search of the Medline/PubMed and Latin American and Caribbean Health Sciences Literature databases (LILACS) databases for studies published up to October 2022. The inclusion criteria were pediatric subjects, which reported the relationship between PhA and the nutritional status with any objective nutritional indicator, and PhA was measured by electric impedance and reported at 50 kHz. We synthesized data from the studies that reported cutoff analysis of PhA with receiver operating characteristic (ROC) curves, mean PhA values presented by nutritional status strata, and correlations between PhA and nutritional status indicators. We assessed the risk of bias by using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies and the Quality Assessment for Diagnostic Accuracy Studies.

Results

Of the 126 studies we identified, 15 met the inclusion criteria. The included studies reported the association between PhA and objective indicators of nutritional status, including weight-for-age z-score (WAZ) <-1 standard deviation (SD) for malnutrition, height-for-age z-score (HAZ) for malnutrition-stunting, body mass index (BMI) for the starvation state, body mass index z-score (BMIz) and BMI for malnutrition, mid-upper arm circumference (MUAC) <11 cm for severe acute malnutrition (SAM), and fat-free mass index z-score (FFMIz) <-2 z-score for moderate malnutrition, among others. The report of these associations between PhA and nutritional status was based on cutoff points generated with ROC curve analysis or comparison of mean PhA values, which were reported stratified by the presence or absence of malnutrition, and correlations between PhA and anthropometric indicators for the evaluation of the nutritional status in the pediatric population. It was difficult to compare the studies due to the heterogeneity of the bioelectrical impedance analysis models used, how PhA was reported (standardized, percentiles, or degrees), and the anthropometric indicators used to diagnose malnutrition.

Conclusion

The early identification of malnutrition is relevant to establish the correct nutritional treatment; PhA appears to be a sensitive indicator of nutritional status and is easy to obtain. Although the results of this review are inadequate to establish PhA cutoff points associated with malnutrition in pediatric populations, in most of the studies, there was an association between PhA and objective indicators of nutritional status.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022362413, identifier: PROSPERO 2022 CRD42022362413.

Nutritional status and volume control in adolescents on chronic hemodialysis

BACKGROUND

Pediatric patients on maintenance hemodialysis (HD) are at risk of both malnutrition and fluid overload. This pilot study aimed to assess correlates of normalized protein catabolic rate (nPCR) in adolescents on chronic HD, in particular fluid status markers.

METHODS

All patients aged 10-18 years on chronic HD in our center between 2017 and 2019 were enrolled. For each patient, mean nPCR was calculated and correlations with the following parameters investigated: dry body weight change in subsequent 3 months in kg (∆BW) and percentage of BW (∆BW%), change in body mass index (∆BMI), preHD systolic and diastolic blood pressure (SBP, DBP), residual urine output, biochemistry, and blood volume monitoring-derived first hour refill index (RI), calculated as ratio between ultrafiltration rate and reduction in relative blood volume in first hour of dialysis.

RESULTS

Seventy-nine nPCR determinations were collected in 23 patients, median age 14.8 years. nPCR significantly correlated with ∆BW, ∆BW%, ∆BMI, spKT/V, and preHD serum creatinine, and negatively correlated with age, DBP SDS (r=-0.466, p=0.025) and RI (r=-0.435, p=0.043). RI was significantly higher in patients with nPCR <1 than those with nPCR above this threshold: 3.2 (1.9-4.7) vs. 1.4 (0.7-1.8) ml/kg/h/% (p=0.021). At multivariable analysis, nPCR remained positively correlated with creatinine and spKt/V, and inversely correlated with RI.

CONCLUSIONS

nPCR is a significant predictor of weight change in adolescents on maintenance HD, and seems associated with creatinine and dialysis adequacy. Inverse correlation with RI suggests possible associations between malnutrition and fluid overload, but larger prospective studies are needed to confirm this. A higher resolution version of the Graphical abstract is available as Supplementary information.

Nutritional Status in Peritoneal Dialysis: Nutritional Guidelines, Adequacy and the Management of Malnutrition

The positive impact of nutritional status on the health and treatment adequacy of peritoneal dialyzed patients has been well established. Protein intake is an important factor used to stratify malnutrition, with inadequate intake leading to protein-energy wasting during the course of therapy. In this review, we discuss the recommendations made by nephrological societies regarding nutrition in this population of dialysis patients. Special attention is given to the intake of protein, and recommendations on the intake of micronutrients are also discussed. Furthermore, factors that may impair nutritional intake and balance are discussed, with mention of the innovative strategies utilized to combat them. In light of inconsistent recommendations that vary between each respective society, as well as a general lack of concise information, it is our intention to call for further research regarding nutritional recommendations in peritoneal dialysis (PD), as well as to advocate for clear and accessible information for patients.

A Novel Objective Nutritional Score for Children on Chronic Peritoneal Dialysis

Objectives

To establish a novel nutritional score based on a series of objective parameters capable of detecting protein-calorie malnutrition in children being treated with chronic peritoneal dialysis (CPD), to test the score in a healthy pediatric population, and to apply it to children on CPD to evaluate their nutritional status.

Study Population

264 healthy school children (mean age 8.69 ± 3.26 years, range 3.05 – 14.98 years) and 29 patients treated with CPD for 1.75 ± 1.02 years (mean age 10.54 ± 6.28 years, range 2.8 – 15.24 years).

Methods

Nutritional status was evaluated by means of three sets of measurements: anthropometric (A1 and A2) and bioimpedance analysis (BIA) measurements. Anthropometry included two sets of measures: set A1 consisted of height (H), weight (W), and body mass index (BMI); set A2 consisted of midarm muscle circumference (MAMC), arm muscle area (AMA), and arm fat area (AFA). The BIA measurements included reactance, phase angle, and distance. All parameters are expressed as standard deviation scores (SDS). Tanner's, Rolland–Cachera's, and Frisancho's data were used as references for H, W, BMI, MAMC, AMA, and AFA; personal data obtained from 551 healthy boys and girls were used for the BIA indices. The nine anthropometry and BIA parameters were given scores of 1 to 5: 5 = > 0 SDS, 4 = ≤ 0 and > –1 SDS, 3 = ≤ –1 and > –2 SDS, 2 = ≤ –2 and > –3 SDS, and 1 = ≤ –3 SDS. Average scores were established for each of A1, A2, and BIA, and then summed to obtain the anthropometry–BIA nutrition (ABN) score. To establish the cutoff value between normal nutritional status and malnutrition, the method was first applied to the 264 healthy children; distribution percentiles were calculated for each area score and the ABN score. The ABN score corresponding to the 3rd percentile was considered the limit of normality and then applied three times to the 29 children on CPD, for a total of 87 nutritional assessments.

Results

The score corresponding to the 3rd percentile in the population of healthy children was 10.33. Among the CPD-treated children, 41.4% of the ABN scores were higher than 10.33 (indicating a state of normal nutrition) and 58.6% were lower (indicating various degrees of malnutrition). Severe malnutrition was found in only 1.1% of the cases. The values of all nine A1, A2, and BIA parameters, as well as serum albumin levels, were significantly higher in patients with an ABN score > 10.33 than in those with a score < 10.33.

Conclusion

The ABN score is a simple and objective method of assessing, in clinical practice, the nutritional status of children on CPD.

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.

Dietary Intake, Nutritional Status, and Body Composition in Children With End-Stage Kidney Disease on Hemodialysis or Peritoneal Dialysis

OBJECTIVE(S)

This study aimed to demonstrate that dietary intake, anthropometric indicators, and body composition in children with end-stage kidney disease differs between those on peritoneal dialysis (PD) and those on hemodialysis (HD).

METHODS

This was a cross-sectional and consecutive study that included 55 children and adolescents with end-stage kidney disease who were undergoing replacement therapy (22 PD patients and 33 HD patients). Two 24-hour dietary recall surveys were conducted for each patient. Anthropometric, biochemical, and body composition indicators were estimated. A Student's t-test and a Mann-Whitney U test were used for the parametric variables, whereas association tests were estimated for the nonparametric variables (i.e., χ², Fisher exact test, and odds ratio). Regression models were designed to predict dietary intake on anthropometric and body composition indicators.

RESULTS

The mid-upper arm circumference was greater on the patients undergoing HD than on the PD patients (odds ratio = 15.8 [95% confidence interval (CI): 2.9, 85.1], P < .001); the arm muscular area was greater in the HD patients than in the PD patients (P = .07). Children on PD had significantly greater creatinine concentration (8.4 ± 3.0 mg/dL vs. 4.6 ± 1.2 mg/dL, P < .001), urea (101 ± 27 mg/dL vs. 50 ± 17 mg/dL, P < .001), and glucose (87 ± 14.4 mg/dL vs. 77 ± 10.2 mg/dL, P = .003). Children on PD had lower lipid intake (31.2 ± 15.8 vs. 40.9 ± 19.1 g/day, P = .032), lower percentage of adequacy of vitamin C (128 ± 66 vs. 146 ± 70, P = .046), and lower sodium (62 ± 43 vs. 79 ± 42, P = .044) than children on HD. Dietary intake predicted 40% to 80% of the variability in the nutritional status in children on PD and 28% to 60% in children on HD.

CONCLUSIONS

Nutritional status is affected in most patients on dialysis treatment, which differs significantly among those who are undergoing PD or HD.

Complications of PEG are not related to age - The result of 10-year multicenter survey

PURPOSE

The aim of this study was to analyze whether the insertion of Percutaneous Endoscopic Gastrostomy (PEG) during infancy is related to higher morbidity. Moreover, we analyzed the structure of indications to PEG placement in various age groups of pediatric patients.

MATERIAL/METHODS

The study involved medical data of children after PEG insertion from six Polish endoscopic centers: infants (<12 months of age), toddlers (12-36 months), and preadolescents (>36 months).

RESULTS

The overall prevalence of early complications associated with PEG insertion was 5.14%; while they were noted in infants and preadolescents, none were recorded in toddlers. The analyzed age groups did not differ significantly in terms of the prevalence of late complications. Cerebral palsy (34.86%) and other chronic neurological conditions (34.29%) were the most frequent indications to PEG insertion in the whole group. Patients with congenital heart defects and multiple defect syndrome were inserted PEG at the youngest age; in contrast, the age at insertion was the highest in cystic fibrosis patients.

CONCLUSIONS

The early qualification to nutritional intervention via endoscopically formed gastrostomy can have important clinical implications with regards to improved therapeutic outcomes and reduced morbidity rates.

Assessment of nutritional status in children with chronic kidney disease and on dialysis

Protein-energy wasting (PEW) is defined as a state of decreased body protein mass and fuel reserves (body protein and fat mass) and is a common complication of chronic kidney disease (CKD). It is multifactorial: the main causative factors are hormonal imbalances and a low nutrient intake, but low residual renal function, inadequate dialysis dose, chronic inflammation and metabolic acidosis are other important contributory factors. Adult PEW has been defined, but there is no accepted definition of pediatric PEW and consequently no precise diagnostic criteria. Assessing nutritional status in children is also complicated by the absence of a gold standard, specific abnormalities in body composition, and the slowly progressive course of the disease. The evaluation of PEW should take into account all of its pathogenetic aspects, which include dietary assessment, clinical and anthropometric assessment (based on weight, height, and body mass index), a panel of biochemical parameters, and a normalized protein catabolic rate (in the case of adolescents on hemodialysis). Bioimpedance indices can be used in individual patients on a regular basis in centers with expertise. The longitudinal follow-up data relating to the above parameters are valuable for comparing patient and normative data. Given the complex nature of PEW, only a multidisciplinary approach can provide an accurate assessment of nutritional status and its derangements in children with CKD and on dialysis.

Nutrition Monitoring in the PICU

The ideal set of variables for nutritional monitoring that may correlate with patient outcomes has not been identified. This is particularly difficult in the PICU patient because many of the standard modes of nutritional monitoring, although well described and available, are fraught with difficulties. Thus, repeated anthropometric and laboratory markers must be jointly analyzed but individually interpreted according to disease and metabolic changes, in order to modify and monitor the nutritional treatment. In addition, isotope techniques are neither clinically feasible nor compatible with the multiple measurements needed to follow progression. On the other hand, indirect alternatives exist but may have pitfalls, of which the clinician must be aware. Risks exist for both overfeeding and underfeeding of PICU patients so that an accurate monitoring of energy expenditure, using targeted indirect calorimetry, is necessary to avoid either extreme. This is very important, since the monitoring of the nutritional status of the critically ill child serves as a guide to early and effective nutritional intervention.

Underweight, overweight and obesity in paediatric dialysis and renal transplant patients

BACKGROUND

The prevalence of childhood overweight is rising worldwide, but in children on renal replacement therapy (RRT) a poor nutritional status is still the primary concern. We aimed to study the prevalence of, and factors associated with, underweight and overweight/obesity in the European paediatric RRT population. Moreover, we assessed the evolution of body mass index (BMI) after the start of RRT.

METHODS

We included 4474 patients younger than 16 years from 25 countries of whom BMI data, obtained between 1995 and 2010, were available within the European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association Registry. Prevalence estimates for under- and overweight/obesity were calculated using age and sex-specific criteria of the World Health Organization (WHO, 0-1 year olds) and the International Obesity Task Force cut-offs (2-15 year olds).

RESULTS

The prevalence of underweight was 3.5%, whereas 20.8% of the patients were overweight and 12.5% obese. Factors associated with being underweight were receiving dialysis treatment and infant age. Among transplanted recipients, a very short stature (OR: 1.64, 95% CI: 1.40-1.92) and glucocorticoid treatment (OR: 1.23, 95% CI: 1.03-1.47) were associated with a higher risk of being overweight/obese. BMI increased post-transplant, and a lower BMI and a higher age at the start of RRT were associated with greater BMI changes during RRT treatment.

CONCLUSIONS

Overweight and obesity, rather than underweight, are highly prevalent in European children on RRT. Short stature among graft recipients had a strong association with overweight, while underweight appears to be only a problem in infants. Our findings suggest that nutritional management in children receiving RRT should focus as much on the prevention and treatment of overweight as on preventing malnutrition.

Anthropometric estimates of total and regional body fat in children aged 6-17 years

AIM

To develop prediction equations for total and regional (trunk, abdominal, arms and legs) body fat using surface anthropometric measures in children aged 6-17 years.

METHODS

This was a cross-sectional correlation study of 70 Caucasian children aged 6-17 years recruited from a larger randomly sampled population-based study. The independent variables included age, mass, height, body mass index, waist and hip girth, and skinfold thicknesses at eight sites. Subscapular/triceps skinfold ratio was also calculated and entered as an independent variable. The dependent variables were total body percentage fat, and fat mass for total body, trunk, abdominal region of interest, arms and legs measured using dual-energy X-ray absorptiometry (DXA). Partial least squares regression was used to determine the best predictive equation for fat percentage or fat mass in each body region in each sex.

RESULTS

Sex-specific prediction equations were developed with high coefficients of determination (r(2)), ranging from 0.869 to 0.936 in boys and from 0.900 to 0.979 in girls, absolute bias was low, and limits of agreement were narrow.

CONCLUSION

Equations were developed, which were able to predict total and regional body fat of Caucasian children aged 6-17 years using surface anthropometric measurements with high predictive accuracy.

The challenges of managing severe dehydrating diarrhoea in a resource-limited setting

Diarrhoea remains one of the most common causes of childhood deaths worldwide despite the widespread use of oral rehydration solution (ORS). The vast majority of the nearly 2 million diarrhoeal deaths occurring annually in children under five years of age are in south Asia and sub-Saharan Africa. Signs of critical illness in severely dehydrated children are poorly recognised, and although considerable efforts have gone into establishing the management of diarrhoeal disease in general, there is surprisingly little understanding of the aetiology, metabolic processes and risk factors for the very high mortality associated with severe dehydrating diarrhoea (SDD). We suggest that in many resource-poor settings, the degree of fluid requirement as well as the prevalence of electrolyte disturbances are seriously under-recognised and may be contributing significantly to mortality. The heterogeneity of children with SDD renders the generic 'one size fits all' approach to fluid and electrolyte management in these critically ill children inadequate. In this review we will highlight SDD as an important target for research in resource-limited settings, and emphasise the need to re-evaluate the efficacy of prevailing intravenous fluid protocols in well conducted multi-centre interventional trials.

Standardized phase angle indicates nutritional status in hospitalized preoperative patients

There is currently no criterion standard to assess nutritional status, and different methods have been used in hospitalized patients. The aim of this study was to investigate the agreement and the association between bioelectrical impedance analysis derived by standardized phase angle (SPA) and other methods used for the nutritional assessment of body composition, metabolic status, and functional status in surgical patients. The hypothesis was that the SPA is effective for evaluating nutritional status in surgical patients; therefore, it could be used when the application of other assessment methods is not possible. The sample consisted of 125 patients (20-94 years of age) before elective gastrointestinal or hernia repair. The participants were from the Surgical Clinic 1 at the University Hospital of the Federal University of Santa Catarina, Florianópolis, SC, Brazil. Nutritional status was evaluated during the preoperative period based on the triceps skinfold thickness, mid-arm circumference, body mass index, percent weight loss, nutritional risk screening 2002 (NRS 2002), subjective global assessment (SGA), and SPA. The agreement between the SPA and the other methods was assessed with the k coefficient. The agreement between the SPA and the methods of nutritional assessment that were investigated for diagnosing malnutrition was moderate for NRS 2002 and SGA, weak for percent weight loss, and poor for triceps skinfold thickness, mid-arm circumference, and body mass index. There was a significant association between SPA and both NRS 2002 and SGA (P < .001). Our results suggest that SPA is able to indicate the risk of nutritional deficiency in the patients assessed. However, good agreement between SPA and the methods investigated was not observed.

Challenges of nutritional assessment in pediatric ICU

PURPOSE OF REVIEW

The nutritional assessment of children in the pediatric ICU is unique in view of the metabolic changes of the underlying disease. This review addresses the use and limitations of anthropometry and laboratorial and body composition markers in the diagnosis of the nutritional status of such patients.

RECENT FINDINGS

The presence of inflammatory activity leads to body composition changes (lean mass reduction) and undernutrition. Nutritional assessment in pediatric ICU must prioritize anthropometric and laboratory markers that can differentiate body composition to detect specific macronutrient and micronutrient deficiencies and assessment of the inflammatory activity.

SUMMARY

Nutritional assessment is one of the main aspects of the pediatric intensive care patient and is the most important tool to avoid hospital undernutrition. There is currently no gold standard for nutritional assessment in the pediatric ICU. The results of anthropometric and laboratory markers must be jointly analyzed, but individually interpreted according to disease and metabolic changes, in order to reach a correct diagnosis of the nutritional status and to plan and monitor the nutritional treatment.

Nutrition assessment and management in children on peritoneal dialysis

Protein-calorie malnutrition, otherwise known as cachexia, is a common problem in children undergoing chronic peritoneal dialysis (PD) and is a frequent source of significant morbidity and mortality. Recent evidence suggests that the main factors involved in the pathogenesis are metabolic acidosis, a decreased response to anabolic hormones, and chronic inflammation, associated with hormonal imbalances and an increased metabolic rate. Given the complexity and multifactorial nature of cachexia, the assessment of nutritional status in children on PD requires a complete history and physical examination; assessment of dietary intake, biochemical indices, and anthropometry; and possibly bioimpedance analysis and combined score systems. Its management should likewise be multidisciplinary and include ensuring an adequate energy and protein intake; optimal metabolic control, with the correction of acidosis, anaemia, and hyperparathyroidism; an optimal (or at least adequate) dialysis dose; and, if necessary, prescription of specific drugs such as recombinant human growth hormone.

Relationship between segmental and whole-body phase angle in peritoneal dialysis patients

The relation between the right-side (RS) electrical impedance phase angle (PA) and segmental PA in five configurations at 50 kHz was analyzed in 23 peritoneal dialysis male patients before complete drainage of the abdominal cavity. The impedance vector (Z/H) components were standardized by the height H of the subjects (R/H and Xc/H). BIVA software was used to analyze the individual RS vector. The Pearson correlation was used to analyze the correlation between RS and segmental configurations. Student's t test and Hotelling's T2 test were used to analyze the separation of groups obtained by BIVA. The highest significant Pearson correlation was between RS and right leg total (RLEGT) in a longitudinal direction (r=0.925, P<0.001). We obtained a significant difference (P<0.05) in R/H, Xc/H (for RS and RLEGT) using Hotelling's T2 test, and in PA using Student's t test. The transverse measurement in the leg (RTRLEG) showed the lowest correlation (r=0.261). In conclusion, we can obtain similar information through the phase angle, whether RS is measured or if we measure on RLEGT. The phase angle of the transverse measurements provides different information from the phase angle of the longitudinal measurements.

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.

Normalized protein catabolic rate versus serum albumin as a nutrition status marker in pediatric patients receiving hemodialysis

BACKGROUND

Protein-energy malnutrition occurs commonly in patients receiving hemodialysis (HD). Although serum albumin (sAlb) is recommended to monitor nutrition status in patients receiving HD, many processes unrelated to nutrition status can affect albumin concentrations.

METHODS

We previously showed normalized protein catabolic rate (nPCR) to be superior to sAlb to reflect improvement in nutrition status in pediatric patients receiving maintenance HD after treatment with intradialytic parenteral nutrition for severe protein-energy malnutrition. We now compare nPCR and sAlb as nutrition status markers for pediatric patients on HD irrespective of current nutrition status.

RESULTS

Forty-four patients comprising 840 months of HD provision were assessed. nPCR was higher for younger patients. Mean nPCR values were significantly lower for adolescent patients with persistent weight loss of at least 2% for at least 3 consecutive months versus patients without persistent weight loss (1.03 +/- 0.29 g/kg/d vs. 1.15 +/- 0.27 g/kg/d, P < .002), and the odds for developing persistent weight loss were four times greater for adolescent patients with nPCR less than 1 g/kg/d. No association between nPCR and weight loss was observed for younger patients. Mean sAlb levels were greater than 4 g/dL for all patient age groups and did not demonstrate a clinically significant difference between patients with or without weight loss.

CONCLUSION

We suggest that nPCR may be useful for monthly nutrition status in adolescent patients receiving maintenance HD and that adolescents with nPCR less than 1 g/kg/d may be at increased risk for subsequent weight loss.

Evaluation of arm anthropometry for assessing pediatric body composition: evidence from healthy and sick children

Arm anthropometry is used as a proxy of body composition in clinical and field research but its validity has not been established in children. To address this issue, mid-upper arm circumference (MUAC) and triceps skinfold thickness (TS) were measured in 110 healthy children aged 4.4-13.9 y (55 boys) and 49 cystic fibrosis (CF) patients aged 8.1-13.4 y (22 boys). Reference values were arm and whole-body fat mass (FM) and fat-free mass (FFM) measured by dual x-ray absorptiometry and four-component model, respectively. Arm fat area (AFA), MUAC, and TS correlated well with arm FM (r = 0.84-0.92) and total FM (r = 0.78-0.92). Arm muscle area (AMA) and MUAC correlated well with arm FFM (r = 0.68-0.82) and total FFM (r = 0.60-0.86). After adjusting for age, sex, and height, arm anthropometry correlated strongly with FM but weakly with FFM. AFA, MUAC, and TS explained 67, 63, and 61% of variability in total FM in healthy children and 70, 72, and 63% in CF. AMA and MUAC explained only 24 and 16% of variability in total FFM in healthy children and 33 and 28% in CF. Arm anthropometry is useful for predicting FM and ranking healthy children and patients for fatness. It has poorer success in predicting regional or total FFM.

A prospective multicentre study of the nutritional status in children on chronic peritoneal dialysis

The anthropometry-bioimpedance analysis-nutrition (ABN) score is a recently proposed objective method of assessing malnutrition in children on chronic peritoneal dialysis (CPD) that uses nine parameters based on anthropometry, skinfold thickness and bioimpedance analysis. The aim of this prospective, cross-sectional study was to apply it to children treated with CPD in seven Italian paediatric nephrology centres, with a score of < 10.33 (the 3rd percentile in a population of 264 healthy children) classifying the children as malnourished. The other considered parameters were age, age at the start of dialysis and duration of dialysis; serum haemoglobin, urea, creatinine, total protein, albumin, transferrin, bicarbonate and C-reactive protein; residual urine output; urinary and peritoneal creatinine clearance; and daily protein and energy intake. The study enrolled 43 patients (mean age 10.2 +/- 4.2 years), 21 of whom (48.8%) had an ABN score of < 10.33: 15 with mild, five with moderate, and one with severe malnutrition. The malnourished patients started CPD at a younger age (P < 0.05) and had a longer duration of dialysis (P < 0.01), and a significant worsening in nutritional status was observed in those treated for more than 12 months of dialysis; they also had significantly lower serum albumin, creatinine and haemoglobin levels. In conclusion, protein-calorie malnutrition is common in children receiving CPD. A younger age at the start of dialysis and a longer duration of treatment are clear risk factors, and counterbalance the long-term viability of CPD in paediatric age.

Bioelectrical impedance analysis in clinical practice: a new perspective on its use beyond body composition equations

PURPOSE OF REVIEW

The bioelectrical impedance analysis is not a direct method for estimating body composition. Its accuracy depends on regression equations, and recent papers have suggested that this approach should not be used in several clinical situations. Another option is to obtain information about the electrical properties of tissues by using raw bioelectrical impedance measurements, resistance and reactance. They can be expressed as a ratio (phase angle) or as a plot (bioelectrical impedance vector analysis). This review describes their use in clinical practice.

RECENT FINDINGS

The phase angle changes with sex and age. It is described as a prognostic tool in many clinical situations. There are some controversies about considering it as a nutritional marker. Studies in burn victims and sickle-cell disease corroborate its ability to evaluate cell membrane function. Bioelectrical impedance vector analysis allows a semi-quantitative estimation of body composition from information from tissue hydration and soft-tissue mass in a plot. It can be used in healthy individuals or patients, for a population or individual evaluation of fluid imbalance or an assessment of soft-tissue mass. It has also been used as a prognostic tool in dialysis and cancer patients.

SUMMARY

The phase angle can be considered a global marker of health, and future studies are needed to prove its utility in intervention studies. Bioelectrical impedance vector analysis has increased its utility in clinical practice, even when the equations may be inaccurate for body composition analysis.

Relationship of bioelectrical impedance parameters to nutrition and survival in peritoneal dialysis patients

BACKGROUND

Malnutrition is highly prevalent in peritoneal dialysis (PD) patients and is associated with higher mortality in these patients. In this study, we have prospectively examined the relationship of bioimpedance indexes to the nutritional status and survival in PD patients.

METHODS

We enrolled 48 PD patients beginning in November 2000. On enrollment, bioelectrical impedance analysis (BIA) (BIA-101; RJL/Akern, Clinton Township, MI, USA) was performed and monthly blood was analyzed for biochemical markers, including prealbumin. Patients were followed until April 2003.

RESULTS

The mean age of PD patients was 51 +/- 15 (SD) years. Fifty-eight percent of the patients were female and 23% of the patients were diabetic. Mean body mass index (BMI) was 25.7 +/- 5.0 kg/m2. Mean resistance, reactance, and phase angle were 521 +/- 104 ohms, 57 +/- 19 ohms, and 6.16 +/- 1.6 degrees, respectively. During the study period, 8 patients (17%) expired. The Kaplan-Meier method was used to compute observed survival. The cumulative observed survival of PD patients with enrollment phase angle greater than or equal to 6 degrees was significantly higher (P = 0.008) than that of patients with phase angle less than 6. Using Cox's multivariate regression analysis, phase angle was an independent predictor (relative risk = 0.39, P = 0.027) of more than two years' survival in PD patients. Serum prealbumin was directly correlated with phase angle (r = 0.54, P < 0.0001), reactance (r = 0.55, P < 0.0001), and resistance (r = 0.29, P = 0.06).

CONCLUSION

BIA indexes reflect nutritional status and may be useful in monitoring nutritional status in PD patients. Phase angle is a strong prognostic index in PD patients. It is useful to incorporate prealbumin and BIA parameters in the regular assessment of PD patients, whose survival may be improved by better management of malnutrition and overall health status.

Bioelectrical impedance vector distribution in the first year of life

OBJECTIVE

We assessed the bioelectrical impedance vector distribution in a sample of healthy infants in the first year of life, which is not available in literature.

METHODS

The study was conducted as a cross-sectional study in 153 healthy Caucasian infants (90 male and 63 female) younger than 1 y, born at full term, adequate for gestational age, free from chronic diseases or growth problems, and not feverish. Z scores for weight, length, cranial circumference, and body mass index for the study population were within the range of +/-1.5 standard deviations according to the Euro-Growth Study references. Concurrent anthropometrics (weight, length, and cranial circumference), body mass index, and bioelectrical impedance (resistance and reactance) measurements were made by the same operator. Whole-body (hand to foot) tetrapolar measurements were performed with a single-frequency (50 kHz), phase-sensitive impedance analyzer. The study population was subdivided into three classes of age for statistical analysis: 0 to 3.99 mo, 4 to 7.99 mo, and 8 to 11.99 mo. Using the bivariate normal distribution of resistance and reactance components standardized by the infant's length, the bivariate 95% confidence limits for the mean impedance vector separated by sex and age groups were calculated and plotted. Further, the bivariate 95%, 75%, and 50% tolerance intervals for individual vector measurements in the first year of life were plotted.

RESULTS

Resistance and reactance values often fluctuated during the first year of life, particularly as raw measurements (without normalization by subject's length). However, 95% confidence ellipses of mean vectors from the three age groups overlapped each other, as did confidence ellipses by sex for each age class, indicating no significant vector migration during the first year of life.

CONCLUSIONS

We obtained an estimate of mean impedance vector in a sample of healthy infants in the first year of life and calculated the bivariate values for an individual vector (95%, 75%, and 50% tolerance ellipses).

Estimates of body water, fat-free mass, and body fat in patients on peritoneal dialysis by anthropometric formulas

BACKGROUND

Anthropometric formulas that are used to estimate body water in peritoneal dialysis patients can also be used to estimate fat-free mass and body fat. Evaluation of body composition by the anthropometric formulas rests on two assumptions: (1) fat contains no water, and (2) the water content of the fat-free mass is constant (72%).

METHODS

We compared estimates of body water, fat-free mass, and body fat by anthropometric formulas to estimates employing dilution of tracer substances to measure body water and standard methods to analyze body composition in studies performed on peritoneal dialysis patients. We also analyzed the potential errors of the estimates of body composition by the formulas.

RESULTS

Estimates of the average body composition provided by the anthropometric formulas agreed with estimates provided by the standard methods. However, these formulas have the potential of introducing large errors when estimating body composition in individuals differing from the average subject, either because the anthropometric formulas do not account for major determinants of body composition, such as physical exercise, nutrition, and catabolic illness, or because these formulas systematically overestimate body water in subjects who are obese or experiencing volume excess.

CONCLUSION

Anthropometric formulas currently in existence can provide only approximations of body composition and may be the sources of large errors in evaluating body composition in peritoneal dialysis patients. The potential errors include estimates of body water. These errors may alter the interpretation of urea kinetic studies in certain categories of peritoneal dialysis patients (e.g., obese subjects).