Effect of energy balance on body weight in patients receiving peritoneal dialysis

Objective To investigate the energy intakes and energy consumption in continuous ambulatory peritoneal dialysis (CAPD) patients,and to identify the possible influence factors for overweight and obesity of CAPD patients.Methods A total of 115 CAPD patients were enrolled from May to December 2011 in Peking University Third Hospital.Based on body mass index (BMI),they were divided into normal group (18.5 kg/m2 ≤ BMI < 24 kg/m2,n =61) and obese group (BMI ≥ 24 kg/m2,n =54).Three-day dietary intakes including dietary energy,protein,fat,and carbohydrates intakes were collected.Glucose absorption from dialysate was measured.Three-day activities were recorded for the calculation of resting energy expenditure (REE) and total energy expenditure (TEE).Body composition of the patients was analyzed.Results There were no significant differences in age,height,dietary energy intake,protein intake,carbohydrate intakes,lean tissue mass,and hydration status between the two groups.Glucose absorption from dialysate and dietary fat intake were significantly higher in the obese group than in the normal group [(1 920.5 ± 506.3) kJ/d vs.(1 673.6 ±535.6) kJ/d,x2 =2.536,P=0.013; (62.5 ±19.8) g/dvs.(53.1 ±18.7) g/d,x2=2.575,P =0.011].Although REE was higher in the obese group as compared with the normal group [(5 066.8 ±1 029.3) kJ/d vs.(4 556.4 ± 799.1) kJ/d,x2 =2.979,P =0.004],there was no significant difference in TEE between the two groups [(7 819.9 ±728.0) kJ/d vs.(7 803.2 ± 1 092.0) kJ/d,x2 =0.770,P =0.939].Logistic regression showed that glucose absorption from dialysate and dietary fat intakes were risk factors for obesity in the study population (OR =1.003,95％ CI =1.000-1.007,P =0.029 ; OR =1.024,95％ CI =1.003-1.046,P =0.027).Conclusions Obese CAPD patients may absorb more glucose from peritoneal dialysate and consume more fat than non-obese CAPD patients,but TEE is not significantly different.It indicates that obese CAPD patients are at positive energy balance.Less use of high glucose dialysate and more physical exercises are recommended for these patients. Key words: Continuous ambulatory peritoneal dialysis ;  Energy intake ;  Energy consumption ;  Body mass index