Body composition in patients treated with peritoneal dialysis

Background. Malnutrition is a common complication in uremia and during maintenance dialysis. Several factors contribute to its development. Different modes of dialysis treatment may differ in their effects on nutritional status. Methods. In order to analyse the nutritional consequences of peritoneal dialysis (PD), body composition analyses were performed in PD patients between February 1993 and March 1996. Body cell mass (BCM) was estimated from measurements of total body potassium (TBK) in a whole-body counter. Total body water (TBW) was determined by measurement of tritiated water. Body fat (BF) was calculated from body weight (BW), TBK and TEW. Observed values were related to predicted (o/p) derived from local population studies. Results. Sixty patients were repeatedly investigated during the study period. Of these, 34 were investigated during the first year of PD. At the start of dialysis, TBK o/p was 0.94 and BF o/p 0.76. No change in body composition was seen during the observation period in the group as a whole. However, within the group individual changes in BW were strongly correlated with individual changes in BF (r = 0.66, P = 0.0001). Twenty-six patients were examined during the second and third year of PD. In this group, BW o/p remained constant over time. However, there was a small but significant decline of TBK o/p and a concomitant increase of BF o/p (P < 0.05). No correlation was observed between changes in TBK and changes in serum albumin. Conclusions. The results of this study indicate, that there may be a risk for further reduction of body cell mass during long-term PD treatment, while body energy stores are maintained or even increased.