Sodium intake and urinary losses in children on dialysis: a European multicenter prospective study.

BACKGROUND: Sodium (Na) balance is unexplored in dialyzed children. We assessed a simplified sodium balance (sNaB) and its correlates in pediatric patients receiving maintenance dialysis. METHODS: Patients < 18 years old on hemodialysis (HD) or peritoneal dialysis (PD) in six European Pediatric Dialysis Working Group centers were recruited. sNaB was calculated from enteral Na, obtained by a 3-day diet diary, Na intake from medications, and 24-h urinary Na (uNa). Primary outcomes were systolic blood pressure and diastolic blood pressure standard deviation scores (SBP and DBP SDS), obtained by 24-h ambulatory blood pressure monitoring or office BP according to age, and interdialytic weight gain (IDWG). RESULTS: Forty-one patients (31 HD), with a median age of 13.3 (IQR 5.2) years, were enrolled. Twelve patients (29.3%) received Na-containing drugs, accounting for 0.6 (0.7) mEq/kg/day. Median total Na intake was 1.5 (1.1) mEq/kg/day, corresponding to 60.6% of the maximum recommended daily intake for healthy children. Median uNa and sNaB were 0.6 (1.8) mEq/kg/day and 0.9 (1.7) mEq/kg/day, respectively. The strongest independent predictor of sNaB in the cohort was urine output. In patients receiving HD, sNaB correlated with IDWG, pre-HD DBP, and first-hour refill index, a volume index based on blood volume monitoring. sNaB was the strongest predictor of IDWG in multiple regression analysis (ß = 0.63; p = 0.005). Neither SBP SDS nor DBP SDS correlated with sNaB. CONCLUSIONS: Na intake is higher than uNa in children on dialysis, and medications may be an important source of Na. sNaB is best predicted by urine output in the population, and it is a significant independent predictor of IDWG in children on HD. A higher resolution version of the Graphical abstract is available as Supplementary information.

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.

Intradialytic cycling in children and young adults on chronic hemodialysis.

BACKGROUND: Intradialytic exercise has been poorly investigated in pediatric patients on chronic hemodialysis (HD). The aim of this study was to assess the acceptability, safety and efficacy of intradialytic exercise in children and young adults on HD. METHODS: The intradialytic exercise program consisted of 30-min sessions of intra-HD exercise using a cycloergometer two to three times a week for 3 months. Study endpoints were the 6-min walking test (6MWT) distances, lung function, number of stands in the chair test, lower extremity strength (LES), anthropometry, dietary intake, dialysis adequacy, incidence of symptomatic sessions, biochemistry and left ventricular mass index. RESULTS: Ten pediatric patients with a median age of 15.3 (range 9.1-24.2) years were enrolled. Two of these underwent kidney transplantation; the remaining eight completed the study and adapted well to the exercise program. At the end of the 3-month study period, all patients had significantly improved results for the 6MWT (+4.9 %; p < 0.05), chair test (+19 %; p < 0.05) and LES (+29.3 %; p < 0.05). Pre-HD albumin, creatinine and total protein levels and post-HD creatinine levels had also significantly improved. The incidence of symptomatic sessions did not increase during the study period. No adverse events occurred. CONCLUSIONS: Based on our results, we conclude that a 30-min exercise program of intradialytic cycling is feasible for the majority of pediatric patients on chronic HD and will be well accepted. Such an exercise program can lead to a significant improvement in the exercise capacity of this patient population.

Correlates of exercise capacity in pediatric patients on chronic hemodialysis.

OBJECTIVE: Pediatric patients on chronic hemodialysis (HD) are at high risk of inactivity and poor physical fitness. The aim of this study was to assess the main correlates of exercise capacity in a cohort of children and young adults on chronic HD. METHODS: Twelve patients on chronic HD (median age 15.6 years; range 9.1-24.2) underwent a 6-minute walking test (WT), spirometry, a 1-minute chair stand test, and the measurement of lower extremity strength. Demographic data, anthropometry (dry weight, height, body mass index, and skinfold thickness, all expressed as standard deviation scores [SDS]), biochemistry (serum albumin, hemoglobin, creatinine, C-reactive protein, bicarbonate), bioimpedance analysis, HD adequacy indices (spKt/V and eKt/V), left ventricular mass index, and medications were also recorded. RESULTS: There was a significant correlation among the distance covered during the WT (median 552 m, range 186-670), forced vital capacity (87.8% of predicted, range 49.7-136), forced expiratory volume in 1 second (86.7%, range 54.7-126.7), and peak expiratory flow (75.5%, 49.7-105.1). All of these indices positively correlated with the weight SDS (r 0.69-0.85), pre-HD serum creatinine (0.57-0.77), and serum albumin (0.60-0.77) and negatively correlated with weekly erythropoietin dose per kilogram of body weight (from -0.64 to -0.83), with P values ranging from <.05 to <.0005. Lower extremity strength (median 11.5 kg, range 3-15) positively correlated with the number of stands at the chair stand test (median 33, range 18-47; r 0.73, P < .05) and serum albumin (r 0.83, P < .01). Distance at the WT, forced vital capacity, lower extremity strength, and the number of stands at the chair stand test all negatively correlated with C-reactive protein levels (r from -0.81 to -0.67, P < .05). CONCLUSION: Our findings show that protein-energy wasting and chronic inflammation are strongly correlated with the exercise capacity of children and young adults on chronic HD.

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 = < or = 0 and > -1 SDS, 3 = < or = -1 and > -2 SDS, 2 = <-2 and > -3 SDS, and 1 = < or = -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.