The ADEMEX study and its implications for peritoneal dialysis adequacy

In an attempt to improve patient outcomes in peritoneal dialysis (PD), national organizations (such as the National Kidney Foundation Dialysis Outcomes Quality Initiative [NKF-DOQI] process) have formulated clinical practice guidelines based on clinical evidence available at the time of development. For "adequacy" of PD it was acknowledged that there was no prospective randomized interventional clinical trial that evaluated the effect of an increase in peritoneal clearance on outcome. The ADEMEX study is the first such study designed to do this. It was well done and adequately powered for the primary analysis. The study findings indicate that over the range of solute clearances studied, an increase in peritoneal clearance is not associated with an incremental improvement in patient outcome. However, it is noted that the cause of dropout was different between groups, with more dropout for "uremia" in the control group. There are also some limitations in the generalizability of the results. First, the exclusion criteria were likely to exclude patients who were small in body size or were high transporters, patients with the highest relative risk of death. Second, although there was an increase in small solute clearance between control and intervention groups, there was not likely to be an increase in clearance of other potential uremic solutes such as middle molecules. Third, the study did not examine outcomes for patients on cycler therapy. Nevertheless it was a provocative, well-run clinical study which does have implications for clinical practice. It confirms that one prescription does not fit all patients, that many patients below current NKF-DOQI targets for small solute clearance are likely to be adequately dialyzed, and provides evidence-based clinical information for national societies to consider when preparing for the next revision of their guidelines.