Usefulness of the dialysis adequacy and transport test in peritoneal dialysis.

Instead of the peritoneal equilibration test (PET), the dialysis adequacy and transport test (DATT) is an easy and convenient method to classify peritoneal transport type. However, the peritoneal transport characteristics obtained from the DATT and the PET are not same in some cases. In the present study, we investigated the ability of the DATT to identify peritoneal transport characteristics in a clinical setting, and we analyzed the characteristics of patients with a discrepancy between the DATT and the PET. We studied 106 patients on continuous ambulatory peritoneal dialysis (CAPD) who underwent 198 simultaneous DATTs and PETs. The 24-hour dialysate-to-plasma ratio of creatinine (D / P(Cr)) from each DATT was compared with the adjusted 4-hour D/P(Cr) from the corresponding PET. Based on the degree of the mean discrepancy between the 24-hour D / P(Cr) and the adjusted 4-hour D / P(Cr) the patients were divided into three groups: Group A patents had 24-hour D / P(Cr) values that were lower than the adjusted 4-hour D / P(Cr) values (n=13). Group B patients had 24-hour D / P(Cr) values that were equivalent to the adjusted 4-hour D / P(Cr) values (n=156). Group C patients had 24-hour D / P(Cr) values that were higher than the adjusted 4-hour D / P(Cr) values (n=29). The comparative analysis among the three groups was adjustedforperitoneal transport characteristics, dialysis adequacy indices, nutrition status, and daily dialysis prescription. The 24-hour D / P(Cr) from the DATT correlated significantly with the 4-hour D / P(Cr) (gamma = 0.759, p < 0.0001). In 156 cases (78.8%), the D / P(Cr) values from the DATT and the PET showed reasonable agreement; but, in 42 cases (21.2%), the values were discordant. In 94 cases (47.5%), the peritoneal transport groups as classified by the DATT and the PET were discordant. The mean difference in D / P(Cr) between the DATT and the PET was 0.07 +/- 0.08, and the DATT differed significantly from the PET in categorizing the low and low-average transport groups (p < 0.05). A significant difference was seen between the three groups in daily exchange volume (group A: 7384.6 +/- 1502.2 mL; group B: 7537.3 +/- 1087.7 mL; group C: 6675.9 +/- 1414.6 mL; p < 0.05) and in the frequency of daily exchanges (group A: 3.7 +/- 0.8 exchanges; group B: 3.8 +/- 0.4 exchanges; group C: 3.4 +/- 0.7 exchanges; p < 0.05). We confirmed that the DATT is an easy and convenient method of identifying peritoneal membrane transport instead of the PET, and that the DATT can be generalized to patients receiving various dialysis prescriptions and to patients receiving four daily exchanges. However, the DATT may be less accurate for CAPD patients with low or low-average transport, and the higher value of D / P(Cr) derived from the DATT, as compared with the PET, is attributable to longer dwell times and a lower dwell volume.