Minimal and optimal peritoneal Kt/V targets: Results of an anuric peritoneal dialysis patient's survival analysis

Background. Residual renal clearance has been shown to be much more predictive of survival than peritoneal clearance, There has been little data to support a target level of peritoneal clearance. A retrospective study was therefore conducted to see how the peritoneal Kt/V had affected the survival of anuric patients in our center. Methods. Over a period of 10 years, there were 150 peritoneal dialysis patients with documented anuria. Their survival was analyzed according to their baseline peritoneal Kt/V at the time of documentation of anuria and at the time of their latest altered peritoneal dialysis (PD) prescription (subsequent Kt/V). Results. There were 90 females and 42 diabetics. The mean age and duration of dialysis were 57.7 +/- 14.7 and 44.1 +/- 31.3 months, respectively. The 2-year and 5-year survival rates were 88.7% and 66.7%, respectively. We found that patients with baseline peritoneal Kt/V below 1.67 had poorer survival after the documentation of anuria than those above [relative risk (RR) 1.985, P = 0.01], although the baseline Kt/V was not an independent risk factors in the whole group of patients. However, such effect was mainly observed in female patients. The survival was identical between those with Kt/V above or below 1.80 (P = 0.98). Among female patients, the group with baseline Kt/V 1.67 to 1.86 had the best survival, followed by those greater than 1.86 and lowest in those below 1.67 (P = 0.0016). For patients with baseline Kt/V below 1.80, those with subsequent Kt/V above 1.76 had better survival than those below (P = 0.033). Conclusion. Our data suggested that a negative effect of peritoneal Kt/V on survival is apparent at a level below 1.67 and there exists a limit of its effect at around 1.80. We suggested a minimal Kt/V target of 1.70 and an optimal target at 1.80 in anuric patients based on survival data. Prospective randomized study is required to confirm this finding.