#5541 EVALUATION OF PROTEIN MALNUTRITION IN CKD PATIENTS ON LOW-PROTEIN DIET

Abstract

Abstract Background and Aims Low-protein diet is considered crucial in patients with chronic kidney disease to slow down kidney function deterioration and control metabolic variables such as serum phosphate, urea and bicarbonate. However, low-protein diet may result in malnutrition if patients do not respect nutritional prescription. Thus, the present study examined the risk of protein malnutrition in CKD patients who started a low-protein diet. Method We analysed anthropometric variables, nutrient intake and body composition in 27 patients with CKD stage 4-5 (M/F 15/12; 69±15 years; 72±18 kg; BMI 27.3±7 kg/m2; serum creatinine 4.9±1.9 mg/dl; GFR 11±4 ml/min; 10 diabetic patients) before and after 3-months of low-protein diet (0.6 g/kg). We estimated nutrient intake with a food frequency questionnaire composed of 37 items and administered by a nutritionist who also prescribed the low-protein diet. We also measured body fat mass (FM) and free-fat mass (FFM) and appendicular skeletal muscle mass using bioimpedentiometry analysis (Akern, Florence). Patients having a protein intake lower than 0.6 g/kg at the nutritional survey was defined as malnourished. Results In the whole sample, after a 3-month diet protein intake decreased from 0.87±0.23 to 0.69±0.18 g/kg (p<0.001; Wilcoxon test). Protein intake was positively correlated with 24-h urine excretion of phosphate at baseline (r = 0.69, p = 0.012) and after 3-monts of diet (r = 0.62, p = 0.02). The diet induced a decrease in body weight (72±18 to 70±17 kg; p = 0.001), BMI (27.3±7 to 26.7±6.8 kg/m2; p = 0.001), FM (24±11 to 21±11 kg; p = 0.006), serum phosphate (1.68±0.33 to 1.52±0.32 mmol/l; p = 0.033) and urea (166±53 to 133±42 mg/dl; p<0.001), whereas FFM, expressed as percentage of body weight, significantly increased (69±9 to 73±8%; p = 0.011). Six patients (22%; 3 diabetic patients) had a protein intake lower than 0.6 g/kg after 3-months of diet. Their protein intake was significantly lower than that in the other 21 patients with protein intake above 0.6 g/kg (0.43±0.1 vs 0.77±0.12 g/kg; p<0.001). These patients had lower FM (14±2 vs 26±11 kg; p = 0.03) and protein intake before starting the low-protein diet than the other 21 patients (0.64±0.06 vs 0.94±21 g/kg; p = 0.003). Patients with protein intake lower than 0.6 g/kg slightly decreased FFM after 3 months of diet compared to the value at baseline (52±7 to 50±7 kg; p = 0.07); conversely the other 21 patients did not change FFM (51±10 to 53±11 kg; p = 0.17), but significantly decreased FM (26±11 to 23±12 kg; p<0.001). Conclusion In conclusion, protein malnutrition may occur during a low-protein diet in CKD patients with a low consumption of proteins before starting this diet. Nutritional analysis is necessary to identify CKD patients at risk of protein malnutrition and to adequately follow up CKD patients on low protein diet.