Analysis of the effects of increasing delivered dialysis treatment to malnourished peritoneal dialysis patients

Background. Poor nutrition is associated with a loss of residual renal func tion and inferior clinical outcome in peritoneal dialysis (PD) patients. Th e value of increasing the PD dose in these individuals is unclear. Methods. An open, prospective, longitudinal, "intention to treat" study was performed on a whole PD population. All patients treated during an 18-mont h recruitment period underwent nutritional assessment and were defined as m alnourished if they had a subjective global assessment (SGA) of B or C and were 5% or more below their desirable body weight. These patients received an intended dialysis dose increase of 25% and were reassessed after six mon ths. Dialysis was not increased in the remaining patients, unless dictated by uremic symptoms. Results. Forty-eight of 153 patients were malnourished by the previously me ntioned criteria. When compared with well-nourished PD patients, they had e vidence of declining nutrition over the previous 12 months, as judged by a loss in body weight and mid-arm circumference (MAC), a reduced creatinine a ppearance, a reduced appetite for protein and calories, and low plasma albu min. They had been on treatment longer and had less residual renal function , resulting in significantly poorer solute clearances. Their peritoneal mem brane function, plasma bicarbonate, comorbid, Karnofsky, Hospital Anxiety a nd Depression (HAD) scores were not different. Following intervention, thei r peritoneal Kt/V-urea was increased by 22.5%, and their total Kt/V-urea by 18%, because of a continued loss of residual function. There was also an i ncrease in dialysis-derived calories. Weight and MAC stabilized after an in itial deterioration, and creatinine appearance increased. There was no incr ease in protein intake, as judged by dietetic interview or protein nitrogen appearance. Oral calorie intake improved, as did plasma albumin after an i nitial decline. Both of these improvements were correlated with the achieve d increase in Kt/V-urea. Objective measures of improvement (plasma albumin and protein nitrogen appearance) were significant in those patients without comorbid disease. Conclusions. These results support the existing evidence that malnutrition is acquired on PD in those patients who lose residual renal function. It is feasible to increase the dialysis dose in these individuals without a detr imental effect, and there is evidence of a modest benefit in patients witho ut comorbidity.