A prospective, randomized multicenter study comparing APD and CAPD treatment. Preservation of residual renal function in dialysis patients: effects of dialysis-technique-related factors. Comparative evaluation of CAPD and PD-plus effectiveness.
The goals for maintenance dialysis treatment are to improve patient survival, reduce patient morbidity, and improve patient quality of life. This is the first randomized prospective study comparing automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD) treatment with respect to quality of life and clinical outcomes in relation to therapy costs.
                A prospective, randomized multicenter study.
                Three Danish CAPD units.
                Thirty-four adequately dialyzed patients with high or high-average peritoneal transport characteristics were included in the study.Twenty-five patients completed the study.
                After randomization, 17 patients were allocated to APD treatment and 17 patients to CAPD treatment for a period of 6 months. Medical and biochemical parameters were evaluated at monthly controls in the CAPD units. Quality-of-life parameters were assessed at baseline and after 6 months by the self-administered short-form SF-36 generic health survey questionnaire supplemented with disease- and treatment-specific questions. Therapy costs were compared by evaluating dialysis-related expenses.
                Quality-of-life parameters, dialysis-related complications, dialysis-related expenses.
                The quality-of-life studies showed that significantly more time for work, family, and social activities was available to patients on APD compared to those on CAPD (p < 0.001). Although the difference was not significant, there was a tendency for less physical and emotional discomfort caused by dialysis fluid in the APD group. Sleep problems, on the other hand, tended to be more marked in the APD group. Any positive effect of APD compared to CAPD on dialysis-related hospital days or complication rates could not be confirmed. With larger patient samples, it is possible, however, that a significant difference might have been achieved. The running costs for APD treatment were US $75 per day and for CAPD treatment US $61 per day.
                If APD treatment can help to keep selected patients vocationally or socially active, paying the extra cost seems reasonable. Residual renal function (RRF) is of paramount importance to dialysis adequacy, morbidity, and mortality, particularly for long-term continuous ambulatory peritoneal dialysis (CAPD) patients. Residual renal function seems to be better preserved in patients on CAPD than in hemodialysis (HD) patients. We analyzed RRF in 45 patients with end-stage renal disease (ESRD), commencing either CAPD or HD, to prospectively define the time course of the decline in RRF, and to evaluate dialysis-technique-related factors such as cardiovascular stability and bioincompatibility.
                Single-center prospective investigation in parallel design with matched pairs.
                Fifteen patients starting CAPD and 15 matched pairs of patients commencing HD were matched according to cause of renal failure and RRF. Hemodialysis patients were assigned to two dialyzer membranes differing markedly in their potential to activate complement and cells (bioincompatibility). Fifteen patients were treated exclusively with the cuprophane membrane (bioincompatible) and the other 15 patients received HD with the high-flux polysulfone membrane (biocompatible).
                Residual renal function was determined at initiation of dialytic therapy and after 6, 12, and 24 months. Dry weight (by chest x ray and diameter of the vena cava) was closely recorded throughout the study, and the number of hypotensive episodes counted.
                Residual renal function declined in both CAPD and HD patients, although this decline was faster in HD patients (2.8 mL/minute after 6 months and 3.7 mL/min after 12 months) than in CAPD patients (0.6 mL/min and 1.4 mL/min after 6 and 12 months respectively). It declined faster in patients with bioincompatible than with biocompatible HD membranes (3.6 mL/min vs 1.9 mL/min after 6 months). Eleven percent of the HD sessions were complicated by clinically relevant blood pressure reductions, but there were no differences between the two dialyzer membrane groups. None of the CAPD patients had documented hypotensive episodes. None of the study patients suffered severe illness or received nephrotoxic antibiotics or radiocontrast media.
                The better preservation of RRF in stable CAPD patients corresponded with greater cardiovascular stability compared to HD patients, independently of the membrane used. Furthermore, there was a significantly higher preservation of RRF in HD patients on polysulfone versus cuprophane membranes, indicating an additional effect of biocompatibility, such as less generation of nephrotoxic substances by the membrane. Thus, starting ESRD patients on HD prior to elective CAPD should be avoided for better preservation of RRF. Decline in residual renal function in CAPD patients often leads to reduced overall solute clearances. Inadequate dialysis has been linked to malnutrition and increased morbidity and mortality rates. Achieving dialysis adequacy targets is often difficult by the conventional method of increasing CAPD exchange volumes. In comparison, substantial increases in solute clearances can be achieved with the use of automated peritoneal dialysis with large fill volumes and an extra daytime exchange.
APD has not been shown to have significant advantages over CAPD in terms of important clinical outcomes. APD may however be considered advantageous in select group of patients such as in the younger PD population and those in employment or education due to its psychosocial advantages. There is a need for a RCT comparing CAPD with APD with sufficiently large patient numbers looking at important clinical outcomes including residual renal function, accompanied by an economic evaluation to clarify the relative clinical and cost-effectiveness of both modalities.