Evaluation of Protein-Energy Wasting and Inflammation on Patients Undergoing Continuous Ambulatory Peritoneal Dialysis and its Correlations

Background: Protein-energy wasting (PEW) and heightened inflammation are prevalent in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and is a strong risk factor for morbidity and mortality in these patients. Evaluation of PEW, prevalence of inflammation as well as interrelationship between various nutritional indices and inflammation has not been studied in much detail in patients undergoing CAPD.

Objectives: This study was conducted to evaluate the interrelationship between PEW and inflammation in patients undergoing CAPD.

Patients and methods: Sixty-three patients undergoing CAPD (M = 28, F = 35) were assessed with regard to their nutritional status and inflammation after a minimum of 3 months CAPD initiation. Nutritional status was assessed by dietary diary, anthropometry, subjective global assessment, and multifrequency bioelectrical impedance analysis (BIA). In addition, their serum albumin, prealbumin, transferrin, and cholesterol level were measured. Also, inflammation in these patients was assessed by High-Sensitivity C-Reactive Protein (hs-CRP > 3 mg/L) and Interleukin-6 (IL-6 > 2 µg/mL). Later on, diagnosis of malnutrition was made based on different methods. Correlation between inflammation and various nutritional assessment indices were analyzed statistically.

Results: Mean (SD) age of the patients was 57.6 (11.6) years. The average (SD) calorie and protein intake per day were 25.5 (4.6) kcal and 0.81 (0.2) mg, respectively. The mean and standard deviation of anthropometry variables of body mass index (BMI), mid-arm circumference (MAC), tricipital skin-fold thickness (TST), mid-arm muscle circumference (MAMC), and corrected mid-arm muscle area (cMAMA) were 23.7 ± 5 kg/m(2), 26.3 ± 4.5 cm, 1.624 ± 0.4 cm, 25.6 ± 4.5 cm, and 45.7 ± 19.7 cm(2), respectively. The mean values of serum protein, albumin, prealbumin, transferrin, cholesterol, triglyceride, hs-CRP, and IL-6 were 5.9 g/dL, 3.0 g/dL, 21.11 mg/dL, 130.6 mg/dL, 155.9 mg/dL, 136.1 mg/dL, 8.8 ± 7.6 mg/L, and 8.4 ± 12.2 µg/dL, respectively. Based on subjective global assessment (SGA); 11.63 (17.4%), 34.63 (54%), and 18.65 (28.6%) patients undergoing CAPD had normal, moderate, and severe malnutrition status, respectively. According to serum albumin level; 13.63 (21%), 39.63 (62%), and 11.63 (17%) patients undergoing CAPD had normal, moderate, and severe malnutrition status, respectively. Finally, based on BMI; 33.63 (52%), 23.63 (37%), and 7.63 (11%) patients undergoing CAPD had normal, moderate, and severe malnutrition status, respectively. About 76.1% and 9.5% of patients undergoing CAPD were malnourished based on lean tissue index (LTI) and fat tissue index (FTI), respectively. Based on hs-CRP and IL-6 findings, 70% (44/63) and 71.8% (45/63) of patients undergoing CAPD had high inflammation, respectively. High sensitive C-reactive protein correlated negatively (significantly) with serum albumin, prealbumin, and transferrin. Interleukin -6 correlated negatively (significantly) with MAC; MAMA; serum albumin, cholesterol, and transferrin. There was significant positive correlation between hs-CRP and IL-6. There is statistically significant difference in total protein intake (g/d), protein intake (g/kg/d), serum protein (g/dL), albumin (g/dL), transferrin (mg/dL), and cholesterol (mg/dL) between patients with and without inflammation.

Conclusions: Protein-energy wasting (80% - 85%) by various methods and inflammation (70%) was very prevalent among patients undergoing CAPD. Inflammatory markers show significant negative correlation with anthropometry and serological markers. Inflammatory markers are suggested to be included in the regular assessment of patients undergoing CAPD, for the better management of protein-energy wasting.