| Abstract|| |
Growth failure is one of the most common and profound clinical manifestation of chronic kidney disease (CKD) in infants, children and adolescents. The aim of this study was to assess the nutritional status of Egyptian children with end-stage renal disease (ESRD) on regular hemodialysis (HD). The study included 50 Egyptian children with ESRD on regular HD, following-up at the Pediatric Nephrology unit, Cairo University. History, including dietary history, was taken for all patients and clinical examination was performed on all of them. Body weight, standing height, height or length SD score, the skin fold thickness, mid-arm circumference, mid-arm muscle circumference and mid-arm muscle circumference area were also assessed. The height of the patients was the most affected anthropometric parameter, as 78% of the patients were shorter (height SDS below -3). Body weight is less affected than height, as body weight SDS of 34% of patients was less than -3 SDS. In addition, the body mass index of 16% of the patients was <3 rd percentile, while only 4% of the patients were >97 th percentile. Although most ESRD patients received adequate protein and caloric intake, their growth was markedly affected, especially with longer period on HD. We suggest that assessment of growth parameters should be performed at a minimum period of every six months in children with CKD stages 2-3. For children with more advanced CKD (stages 4-5 and 5D), more frequent evaluation may be warranted due to the greater risk of abnormalities.
|How to cite this article:|
Lotfy HM, Sabry SM, Ghobrial EE, Abed SA. The effect of regular hemodialysis on the nutritional status of children with end-stage renal disease. Saudi J Kidney Dis Transpl 2015;26:263-70
|How to cite this URL:|
Lotfy HM, Sabry SM, Ghobrial EE, Abed SA. The effect of regular hemodialysis on the nutritional status of children with end-stage renal disease. Saudi J Kidney Dis Transpl [serial online] 2015 [cited 2019 May 22];26:263-70. Available from: http://www.sjkdt.org/text.asp?2015/26/2/263/152416
| Introduction|| |
Malnutrition is a common and serious complication of chronic kidney disease (CKD), and is associated with increased morbidity and mortality.  Contributing factors to this malnutrition include poor appetite, various co-morbidities, dietary restrictions, inflammation, infection, metabolic acidosis and oxidative stress. 
Nutritional status is particularly important in children as it influences growth and sexual and neuro-cognitive development. Thus, its accurate and regular assessment is highly recommended in patients on regular hemodialysis (HD). 
Growth failure is one of the commonest and a profound clinical manifestation of CKD in infants, children and adolescents.  Height age is usually more retarded than bone age. Attempts to improve growth include adequate dialysis, improved nutrition, renal osteodystrophy management, correction of metabolic acidosis and administration of recombinant human growth hormone (rhGH). 
Children with height SD scores <2.5 at dialysis initiation were found to have 2.07 times the risk of death and to spend 0.22 more days per month in the hospital compared to those with height SD scores >-2.5.  Body mass index (BMI)-for-height-age has been suggested as a more appropriate method of standardization in renal disease. 
Kidney disease wasting (KDW) in chronic dialysis patients affects approximately one-third of HD patients. Serum levels of inflammatory markers are increased and numerous causes of chronic inflammation may be present. 
Hypoalbuminemia is frequently seen in patients with CKD and has been consistently shown to be associated with increased mortality in children.  Protein catabolic rates of less than 1 g/kg/day are indicative of protein malnutrition and should lead to institution of corrective steps.  Two methods of obtaining dietary information may be used; prospectively, by means of a three-day diary, or retrospectively, by interview with recall of intake over the previous 24 h.  At present, the estimated dry weight, in combination with stature, remains the usual central component of the nutritional evaluation. 
Skin fold thickness is the most common method of determining body fatness in clinical practice. Mild-to-moderate deficits in triceps-skin fold thickness have been reported in children with CKD.  Mid-arm circumference (MAC), mid-arm muscle circumference (MAMC) and mid-arm muscle circumference area (MAMA) are measures used as indices of total muscle mass. 
| Objectives|| |
The aim of this study is to assess the growth and the nutritional status in ESRD children on regular HD and to correlate their caloric and protein intake with anthropometric measurements.
| Patients and Methods|| |
The study included 50 Egyptian children below 18 years with ESRD on regular HD for at least three months and being followed-up at the Pediatric Nephrology and Transplantation Center, Cairo University. HD machines with volumetric control (Dialysis system 4008B and 4008S, Fresenius Medical Care, Hamburg, Germany) were used. The standard dialysis bath consisted of sodium 140 mEq/L, potassium 2 mEq/L, calcium 3 mEq/L and bicarbonate 35 mEq/L.
Dialysis prescription was based on delivering a minimum single-pool Kt/v of 1.2. The dialysis session duration ranged from 3.5 and 4 h. Blood pump flow ranged from 80-180 mL/ min. Dialysis sessions were prescribed three times/week in most patients, except for some patients who were dialyzing four times/week.
The ultrafiltration rate was programmed to reach the patient's optimal dry weight, which is defined as the post-dialysis body weight below which the patients developed symptomatic hypotension or muscle cramps in the absence of edema. Dialyzer size was chosen to match each patient's body surface area and to limit the circuit extracorporeal volume to <10% of patient total body volume.
Filters used were those with polysulfone membranes, with surface areas 0.4, 0.7, 1.0 and 1.3 for F3, F4, F5 and F6 dialyzers respectively (Fresenius Medical Care, Hamburg, Germany). The dialysate flow rate (Qd) was 500 mL/min. Heparin was used for anticoagulation. Some patients had heparin-free dialysis, e.g. those having thrombocytopenia or bleeding tendency. The duration of HD ranged from 7-108 months (mean 54.4 ± 27.8 months). The vascular accesses used were AVF in 66%, temporary catheter in 20% and permanent catheter in 14%.
For all patients
Full history was taken, including:
- Demographic data, original renal disease, vascular access, HD duration and co-morbidities.
- Dietary assessment for three days (1) and all nutrients were computer analyzed (qualitatively/quantitatively) using the Food Composition Table for Egypt (2006).  Protein and calorie intake were calculated and expressed as a percentage of the recommended dietary allowance of protein and calories for CKD.
None of the patients were on tube feeding or parenteral nutrition.
Full examination was carried out, including:
- Post-dialysis body weight (in kg), which coincided with the dry weight, standing height (in cm) and height or length SD score.
Measures of growth and nutritional status are often expressed as SD scores or Z scores. An SD score is the difference, in SD units, between an individual's measure and the mean for children with the same characteristics. SD score = observed - mean for age and sex/SD for age and sex (Baumgartner et al, 1986). 
Anthropometric data were expressed in standard deviation score (SDS) to allow comparison of data irrespective of age and sex, and measurements were referred to reference data derived from Egyptian Growth Charts.  The Z score of the anthropometric measurements were calculated for each case according to the following formula:
(Baumgartner et al, 1986)  Growth velocity of these patients was not calculated as most of them had no previously recorded heights.
- The skin fold thickness (in mm):
This was taken by using a Holtain skin fold thickness caliper, an instrument that has been designed to give a constant pressure of 10 g/m 2 over its entire operating range. Its dial was marked in divisions of 0.2 mm, but the reading of 0.1 mm can be easily estimated. The thumb and the four fingers of the left hand picked up a fold of skin and subcutaneous tissue and pinched it away from the underlying muscle. The caliper was applied to the fold a little below the pinch point and the right hand was allowed to fully relax its grip on the trigger, so that the jaws can exert their full pressure. The pressure was recorded 3 s after the jaws were applied to the fold.
- Triceps skin fold (TSF) thickness:
The measure was taken on both the right and the left arms and then the mean was taken. The child was standing with his back to the measurer and his arm relaxed, with the palm facing the lateral thigh, the tips of the acromion process and olecranon were placed and a mark was made on the skin (a point midway between them and parallel to the long axis of the arm). Then, the skin fold was picked up between the index finger and the thumb of the left hand, over the posterior surface of the triceps muscle, 1 cm above the mark, on a vertical line passing upwards above the olecranon to the acromion. Care was taken not to include the underlying muscle. The caliper jaws were applied at the marked level.
- Subscapular skin fold thickness:
The subject's shoulder were erect and the arm beside the body. The skin fold was picked up at the inferior angle of the scapula and the caliper jaws were applied.
MAC is measured in the upper arm, midway between the acromion and the olecranon process, with a flexible measuring tape.
MAMC and MAMA were estimated by using equations that incorporate MAC and the TSF thickness measure.
(Baumgartner et al, 1986) 
All measurements were taken after dialysis to exclude the effect of edema that was present in some patients before dialysis due to volume overload and disappears at the end of dialysis. Almost all patients used to reach their euvolemic state by the end of dialysis. Ten percent of patients remained hypertensive after dialysis due to renovascular causes (these patients are usually not compliant to antihypertensive therapy).
Records were reviewed for the past year and the mean of four values for serum albumin, hemoglobin percentage, hematocrit, serum calcium, phosphorus, alkaline phosphatase, predialysis blood urea nitrogen and iron indices were considered.  Efficiency of dialysis was measured by Kt/V calculated by a single-pool natural logarithm formula from pre- and post-dialysis urea and ultrafiltration.
The inflammatory catabolic parameters such as high-sensitive C-reactive protein and pre-albumin were only calculated individually for some patients; therefore, the results are not included here.
All our patients started HD when their glomerular filtration rate was <10 mL/min/1.73 m 2 and none of them had heavy-range proteinuria.
Lipid profile was not performed routinely as long as the patient had no apparent risk factors for the same.
| Statistical Analysis|| |
Data were tabulated and statistically analyzed using appropriate methods. For quantitative variables, mean, median, standard deviation, range, minimum and maximum were used. Frequency and percentage were presented for qualitative variables. Chi square and Fisher's Exact tests were used to estimate the difference in the qualitative variables.
| Results|| |
The present study included 50 patients. Their mean age was 10.7 ± 3.6 years (range 3-16 years). The male to female ratio was 1:1. According to the original renal disease, patients were classified into the following groups: Urological disorders (32%), glomerular diseases (14%), hypoplastic kidney (20%), chronic interstitial nephritis (8%), metabolic (6%) and unknown (20%), as shown in [Figure 1].
The vascular accesses used were AVF (66%), temporary catheter (20%) and permanent catheter (14%). Their duration on HD ranged from 7-108 months (mean 54.4 ± 27.8 months).
The dialysis efficiency, as measured by Kt/v, had a mean of 1.8 ± 0.4. All patients had Kt/v >1.2.
The hematocrit of 54% of patients was less than 33% (target level), while 66% of patients had hemoglobin level below 11 g/dL, 70% of the patients had serum calcium below 8.8 mg/dL and all the patients had blood urea nitrogen above the normal level.
The average level of serum phosphorous was 5 ± 1.9, serum total calcium was 8 ± 1.6 and serum alkaline phosphatase was 512 ± 442.
Vitamin D levels were not performed in any of the patients. Parathyroid hormone levels were performed yearly, except in patients with remarkably disturbed calcium/phosphorus status or with severe skeletal complaints, where it was done more frequently.
Most of the patients were not compliant to their medications due to their young age, and this really added to our problem in dealing with them.
Parameters used to assess nutritional status in our study group
Study of the caloric intake of our patients revealed that it ranged from 547 - 2179 kcal/ day (mean 1305 ± 401) and 22 - 102 kcal/kg/ day (mean 60.3 ± 17). The percentage of the recommended dietary allowances (RDA) caloric intakes ranged from 19 - 216% (mean 107 ± 36.6%). Twelve percent of the patients received caloric intake <70% of the RDA and 56% received between 70% and 120%, while 32% of the patients received >120% of the RDA.
Protein intake of the study group ranged from 25-105 g/day (mean 58.4 ± 19.8) and 0.8 - 3.8 g/kg/day (mean 2.6 ± 0.63), representing a percentage of RDA ranging from 55 - 271% (mean 178% ± 44%). Two percent of our patients received protein <70% of the RDA of protein intake and 94% received >120%, while the remaining 4% received 70 - 120% of the RDA of the protein intake.
Eighty-eight (88) percent of our patients had a normal or increased caloric intake, and, despite this, 78% had a height below the third percentile.
The results revealed that the serum albumin of 20 patients was <3.5 g, while 30 patients had serum albumin >3.5 g.
Anthropometric measurements Regarding anthropometric measurements of our study group, the height was the most affected parameter, as 78% of the patients were short (height SDS below -3, range 0.0 - -9.2 and mean -4.6 ± 2.1). The body weight was less affected than the height, as body weight SDS of 34% of the patients was less than -3 SDS (range 1.6 - -13.8, mean -2.84 ± 2.38). In addition, the BMI of 16% of the patients was <3 rd percentile, while only 4% of the patient were >97 th percentile. The BMI ranged from 8.9 - 23.4.
The arm indices measurement of our study group revealed that the MAC measurements ranged from 120 - 270 mm (mean 180.2 ± 31.1), with MAC of 62% below the 3 rd percentile, and 38% of the patients lay in between the normal range (5 th - 90 th ). The MAMC measurement of our study group ranged from 88.6 to 248 (mean 152.6 ± 27.7) and the patients below the 3rd percentile were 62%; 2% of the patients were above the 90 th percentile and the remaining 36% were in the normal range (5 th - 90 th ). The MAMA measurements of our study group ranged from 625 - 4898 (mean 1914 ± 713.4) and the MAMA below the 5 th percentile represented 66% of the patients, while 2% of the patients were above the 90 th percentile and the remaining 32% were in the normal range (5 th -90 th ).
The TSF measurements of our study group ranged from 4 - 22 mm (mean 8.8 ± 3.5). Patients with TSF measurements below the 5 th percentile were 12%. Two percent (2%) of the patients were above the 90 th percentile, while 86% of the patients were in the normal range (5 th - 90 th ).
Caloric intake/kg/day showed a negative correlation with BMI (r = -0.377, P = 0.007) and TSF (r = -0.406, P = 0.003) [Figure 2] and [Figure 3], while protein intake/kg/day showed no correlation with BMI, albumin, height SDS and arm indices.
|Figure 3: Correlation between caloric intake/kg/day and TSF (r = -0.406, P = 0.003).|
Click here to view
The duration of HD showed a significant negative correlation with height SDS (r = -0.428, P = <0.0001) [Figure 4]; thus, the longer the duration of HD, the more affected was the growth, but there was no correlation with BMI.
|Figure 4: Correlation between duration of HD and height SDS (r = -0.428, P = <0.0001).|
Click here to view
| Discussion|| |
The sequelae of KDW are numerous, including malaise, fatigue, poor rehabilitation, impaired wound healing, increased susceptibility to infection, increased rate of hospitalization and mortality. Consequently, assessment of the nutritional status for children receiving maintenance dialysis is extremely important.  The Kidney Disease Outcome Quality Initiative (K/DOQI) Clinical Practice guidelines for Nutrition in Chronic Renal Failure (NKF-K/ DOQI, 2000)  stated that no single measure provides a complete picture of nutritional status and that many different measures are recommended for assessment of the nutritional status.
In the present work, urological disorders, followed by hypoplastic, unknown and glomerular disease, were the most frequent causes of CKD. This is in concordance with the results from Safouh (1996),  where unknown causes, nephritis, congenital anomalies, posterior urethral valves (PUV) and stones were the most common causes of CRF in Egyptian children.
Except for the high percentage of unknown causes, our results were also in concordance with other studies,  where urological causes and nephritis were the most common causes of CRF in children. The strikingly high percentage of unknown causes of CRF among our patients may be because our center is a tertiary referral center and cases were usually referred to us late. Another factor could be the delayed diagnosis of cases until CRF occurs when etiological work up is usually non-contributory.
In the present work, height was the most severely affected anthropometric parameter in children with CKD on regular HD (92%), which is in concordance with other Egyptian studies.  On the other hand, data from developed countries generally show a less severe effect on height, and the literature shows that only 36.6%, 47.0% and 43% among children with chronic renal insufficiency, dialysis and transplantation, respectively, have short stature. 
The increased effect on height in our country may be due to delay in the diagnosis as well as in implementing interventional measures in CKD patients. Also, our center refers uncomplicated children with higher weights (most of them have acquired causes of renal failure) to other centers; therefore, most of our remaining cases have congenital or hereditary causes, which have effects on growth earlier in the course of the disease.
In the present study, the BMI of 16% of the patients was <3 rd percentile, while only 4% of the patients were >97 th percentile, with a BMI of 17.1 ± 2.84, which are in concordance with results from Be ba et al,  with a mean BMI of 17.1 ± 1.6.
The high mean caloric intake of our patients (107 ± 36.6%) is mainly due to consumption of cheap sources of energy, like bread. The NKF-K/DOQI (2000) recommended that children on dialysis should have their initial dietary protein intake based on the RDA for chronological age, with an additional increment of 0.4 g/kg/day for patients on HD or their anticipated peritoneal losses for children on peritoneal dialysis. It also recommended that diet should consist of protein of high biological value. In the present study, caloric intake showed a negative correlation with BMI and TSF, which does not coincide with the results of Rees and Show (2007),  who reported that in CRF restoration of normal energy requirements to 100% of RDA of calories allows for catch-up growth in children under two years of age and shows some benefit in older children. Ledermann et al (1999) and Ellis et al (2001) reported an SDS (r = -0.428, P = <0.0001) among their patients, but showed no change after increasing caloric supplementation to patients above the age of three years.
In the present study, 94% of the patients had adequate protein intake >120% of the RDA of protein, with no significant correlation between protein intake and height SDS, BMI, albumin and arm indices (MAC, MAMC and MAMA), probably because our patients depend on low biological value proteins. The serum albumin being a marker of nutritional status was <3.5 g in 20 of our patients and >3.5 g in the remaining.
In the present work, height SDS showed a significant negative correlation with the duration of HD, which is in concordance with the results from Stefanidis (2005). 
The limitation of the study was the small sample size; otherwise, there were no other limitations.
| Conclusion|| |
Although most ESRD patients received adequate protein and caloric intake, their growth (evidenced by height and weight parameters) was markedly affected. The longer the HD duration, the more severe was the effect on growth. Management of CKD children should include a team of pediatric nephrologists, endocrinologists, dietitians and clinical nursing specialists.
| Acknowledgments|| |
The authors thank all the patients who participated in the study and their parents.
Conflict of interest: None declared.
This study was approved by the ethical scientific committee of the Cairo University Hospital and was conducted in accordance with the university's bylaws for human research after obtaining informed consent from the patients.
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Dr. Emad E Ghobrial
Hemodialysis Unit of Center of Pediatric Nephrology and Transplantation, New Children's Hospital, Faculty of Medicine, Cairo University, Cairo
[Figure 1], [Figure 2], [Figure 3], [Figure 4]