[Adequate peritoneal dialysis--new guidelines?].
The role of peritoneal dialysis (PD) in renal replacement therapy has been well established. However, there is persisting controversy about the amount of dialysis that is required for optimal outcome. On the basis of the results of clinical studies of patients treated with continuous ambulatory peritoneal dialysis (CAPD), NFK-DOQI guidelines recommended achieving a Kt/Vurea of >or=2.0 per week and a total creatinine clearance of >or=50 l/week/1.73 m2 (low/low-average transporters) to 60 l/week/1.73 m2 (high/high-average transporters). In automated PD, the targets are slightly higher (>or=2.1 per week and >or=63 l/week/1.73 m2, respectively). In the DOQI guidelines, renal and peritoneal clearances are assumed to be equivalent; therefore it has been supposed that increasing the dialysis dose could compensate for the loss of residual renal function (RRF). Several retrospective studies analyzed the effect of peritoneal and renal clearances separately and did not find a correlation between peritoneal small-solute clearance and mortality. However, RRF was an important factor influencing mortality of PD patients. The Adequacy of Peritoneal Dialysis in Mexico (ADEMEX) study is a randomized, prospective study that was designed to investigate the effect of PD dose on clinical outcome in CAPD patients. This study also showed that RRF, but not peritoneal clearance, predicted clinical outcome. An increase of PD dose (from 1.8 to 2.27 Kt/V per week) did not improve patient survival or technique survival. On the basis of the result of ADEMEX and some other clinical studies, a combined renal and peritoneal Kt/V of 1.8/week appears to be adequate in most clinically stable PD patients without signs of malnutrition. Nevertheless, there are no patient-survival data on the influence of peritoneal small-solute clearances, which are markedly higher than those recommended in the DOQI guidelines. On the other hand, important determinants of adequate PD include not only small-solute clearances but also middle-molecule clearances, preservation of RRF, careful attention to volume status, treatment of cardiovascular risk factors, and treatment of malnutrition and other comorbidities.