Arch Hellen Med, 17(1), January-February 2000, 74-76
proteins in malnourished hemodialysis patients
on protein supplemented diet
VAZELOV,1 F. RIBAROVA2
1Hemodialysis Centre, University Hospital "Queen Giovanna",
2 National Centre of Hygiene, Medical Ecology and Nutrition, Sofia, Bulgaria
Chronic renal failure, Hemodialysis, Malnutrition, Plasma
Malnutrition is a common complication of chronic renal failure (CRF), especially in patients on hemodialysis (HD) therapy. It affects a high percentage of the hemo dialysis population and is closely related to increased morbidity and mortality.1 Biochemical investigations are widely used in assessment of the nutritional status in order to diagnose protein-energy malnutrition (PEM).2–4 Changes in the concentrations of various plasma proteins correlate with visceral protein synthesis and affect the nutritional status. Sensitive markers for the diagnosis of PEM are the serum proteins albumin, prealbumin, total protein (TP) and transferrin.
Protein-energy supplementation of the usual diet is a method often used to treat dialysis related malnutrition. Oral supplements are comparatively inexpensive and yet can be effective. The changes in serum protein levels can be considered as predictors of the effect of the therapy of malnutrition.
The aim of this investigation was to ascertain the changes in several plasma proteins, albumin, prealbumin, TP and transferrin, as indicators of PEM in malnourished HD patients treated with the oral protein supplement “Nutridial”.
MATERIAL AND METHOD
The study included 28 patients (16F, 12M), mean age 43.6 years (range 24 to 67 years) and mean duration of dialysis treatment 105.8 months (range 5 to 207 months), with signs of PEM but without clinical symptoms of intercurrent illness. Selection criteria for inclusion in the study were: low levels of albumin and TP, low predialysis levels of urea and creatinine, and a tendency for weight loss. The primary renal diseases of the patients were: chronic glomerulonephritis in 10 cases, chronic pyelone phritis in 9 cases, polycystic kidney disease in 3 cases and systemic lupus erythematosus nephropathy in one case. The HD treatment schedule was as follows: thrice weekly dialysis sessions of 12–13.5 hours, acetate bath, polysulphone and cellulose-acetate membranes.
The protein supplement in powder form “Nutridial” (tabl. 1), which was developed using mathematical modelling of the aminoacid content, was ingested at an average of 0.3 g protein/kg BW/day. The quantity of the supplement given individually to the patients was calculated as the difference between the protein intake proposed for hemodialysis (1.2 g/kg BW/day) and the real intake established in this group by seven-day dietetic diaries (0.93 g/kg BW/day).
Blood for testing was drawn from the arteriovenous fistula via the needles inserted at monitored the start of the dialysis procedure. The parameters, albumin, TP, prealbumin and transferrin, were measured at the start and at 3 and 6 months by autoanalyzers Hitachi 704, RA-500 and radial immunodiffusion.
All values were expressed as mean plus/minus standard deviation.
RESULTS AND DISCUSSION
The levels of the plasma proteins over the course of the investigation are shown in table 2 .
Albumin level is the parameter most often used when assessment of nutritional status is made, since it shows significant correlation with other important parameters such as creatinine, prealbumin, triceps skinfold thickness (TST), arm-muscle circumference (AMC). The levels of albumin in the course of supplementation showed an increase which was most pronounced at the third month (38.04±4.40 g/L vs 35.52±3.67, P<0.05), but one month after discontinuation of “Nutridial” their values (35.92± 3.66 g/L) returned to close to the baseline level which suggests that the improvement of the albumin status was related to protein supplementation.
Changes were similar to those observed for albumin were registered for TP. From 66.96±4.26 it was elevated to 71.08±6.02 g/L, P<0.05, at the third month. Insignificant decline was demonstrated at the sixth month (69.33±2.85 g/L). Even one month after the end of the supplementation, it remained higher (67.37±4.58 g/L) compared to the starting point. Although TP is not considered a very reliable or sensitive parameter in the diagnosis of malnutrition, its fluctuations exhibit the same pattern as albumin and confirm the positive role of the optimized protein intake.
The levels of transferrin are highly influenced by the iron content in the organism, which in patients with CRF on dialysis treatment may be either increased from numerous blood transfusions or decreased due to insufficient food intake or recombinant human erythropoietin treatment without adequate iron supplementation, which lowers its diagnostic value.2,5 In this investigation the iron status of the patients was not ascertained. The transferrin levels showed steady although insignificant elevation from 2.63±0.39 g/L to 2.70±0.58 g/L at the sixth month.
The level of prealbumin due to its short half life changes quickly when the protein dietary intake is increased. This allows its application in assessment of whether treatment of malnutrition is effective independent of the level.6,7 In this study the positive effect of protein supplementation with “Nutridial” on other nutritional parameters also affected prealbumin which rose from a base level of 0.328±0.087 g/L through 0.333±0.157 at the 3rd month to 0.358±0.097 at the 6th month. The tendency for increase continued after the end of the supplementation (7th month), independent of the fact that the half life of this protein is shorter than the period between the last two measurements. These results correspond with other published data. According to Miller and coauthors, serum prealbumin levels in patients with CRF, independent of their nutritional status, are normal or elevated due to diminished renal excretion.8 Cano found that prealbumin is the most predictive indicator of the effect of the therapy, since it correlates closely with five other nutritional parameters (body weight, albumin, creatinine, TST, AMC) and three complications: infections, the presence of HBsAg and mortality.9 Ikizler and co-workers consider that albumin, prealbumin and transferrin levels in HD patients are highly influenced by inflammation.10
The data for the plasma proteins studied correlates with other investigations by the authors on the plasma ami noacid spectrum in similar groups of malnourished HD patients on a diet supplemented with “Nutridial”.11,12
It can be concluded that the plasma proteins studied, albumin, TP, prealbumin and transferrin, can be used as markers of malnutrition in patients with CRF on HD treatment and in assessment of the effect of protein supplementation. The newly developed protein product “Nutridial” can be recommended for protein supplementation in such groups of patients.