Adequacy of peritoneal dialysis: Kt/V revisited

OBJECTIVE: Kt/V urea has been used to assess adequacy of peritoneal dialysis. However, Kt/V urea only reflects the clearance of solute without taking into consideration the effects of dietary protein intake (DPI). The objective of this study is to evaluate the value of Kt/V based on nitrogen balance and to observe if it is the best adequacy index. METHODS: On the premise that nitrogen balance is obtained, we calculated the minimal adequate dialysate volume and dialysis index (DI), Kt/V and solute removal index (SRI). We compared the values of DI, Kt/V and SRI to evaluate the adequacy of peritoneal dialysis. RESULTS: Kt/V was changed with DPI and body weight of continuous ambulatory peritoneal dialysis (CAPD) patients. We cannot define adequate dialysis with a single value while DPI and body weight are different since CAPD, SRI and Kt/V are numerically equal. However, dialysis index (DI) can reflect the minimal adequate dialysate volume when DPI and body weight are different and, thus, reflects the adequacy of dialysis. CONCLUSIONS: DI reflects the balance between DPI and solute clearance; thus, it is more useful to evaluate dialysis adequacy than Kt/V and SRI in clinically stable peritoneal dialysis patients.Changjiang Scholars Program of Ministry of Education of the People's Republic of China; Ministry of EducationSCI(E)ARTICLElingw1228@sohu.com71272-12751