Nutritional Considerations in Indian Patients on PD

Abstract

Malnutrition inevitably accompanies Chronic Kidney Disease (CKD) and dialysis. Markers of malnutrition like low serum albumin have been shown to correlate independently with higher mortality in dialysis patients (1).Malnutrition is seen in both Hemodiaysis (HD) and Peritoneal Dialysis (PD) patients. The incidence has been described at 10-70% in HD and 1851% in PD patients (2,3). The causes of malnutrition in dialysis patients can be manifolddialysis factors, biochemical factors, gastrointestinal factors, miscellaneous factors, and low socio-economic status (4). Miscellaneous factors include depression, multiple medications, recurrent hospitalizations, and underlying illness. Modality of dialysis also affects nutritional status. There are factors unique to each both PD and HD that may contribute to the overall malnutrition. In PD, loss of albumin in PD fluid may range from 5.5-11.8 gms per day (5).In comparison, low flux dialysers account for amino acid losses of 5.6-7.1 gm/day in HD patients(6).Thus PD patients maintain lower serum albumin than age and weight controlled HD patients. Other causes responsible for hypoalbuminemia in PD patients include older age, etiology of renal failure, transport status, and chronic inflammation. Anorexia can result from distention due to fluid in the abdomen. Episodes of peritonitis can cause protein losses of upto 15 gm per day (7). Overhydration, and early satiety due to absorption of glucose from PD fluid can also be a cause of malnutrition in PD (8).Hospitalisation of dialysis patients is estimated to lead to them missing upto 20% of their lunches and dinners, with calorie deficits of upto 3000kcal/week (9).Other factors may ultimately impinge upon a dialysis patients nutritional well being. Blindness, amputations, dementia, depression and stroke are some factors adding to the nutritional challenges. Disabilities are more in HD patients than in PD, and is also more common in diabetics than non diabetics (10).As the number of diabetics on PD increased exponentially, malnutrition is also expected to increase with the same rate. Even though malnutrition is very common and strongly predicts outcome, malnutrition is not thought to directly cause death. Rather, a combination of malnutrition, inflammation and cardiovascular disease may be interrelated in dialysis (11,12). Serum levels of CRP and interleukin-6 (IL-6, which is a pivotal proinflammatory cytokine involved in systemic inflammation) were found to be significantly elevated in malnourished HD and PD patients. As a marker of systemic inflammatory reaction, serum CRP is now regarded as the best predictor for development of cardiovascular disease in the general population as well as in dialysis patients .These factors led to the proposal that malnutrition be characterised as Type1 and Type 2 (12).Type 1