Haemodialysate: long neglected, difficult to optimize, may modify hard outcomes.

In two recent CKJ reviews, experts (Basile and Lomonte and Locatelli et al.) have reviewed haemodialysate composition. A long-neglected issue, observational studies have associated the composition of haemodialysate to adverse outcomes. However, the scarcity of clinical trial-derived information results in limited guideline recommendations on the issue. Indeed, guidelines have more frequently indicated what not to do rather than what to do. In this setting, expert opinion becomes invaluable. In designing haemodialysate composition, a balance should be struck between the need to correct within a time frame of around 4 hours the electrolyte and water imbalances that take 48 to 72 h to build, with the need for gradual correction of these imbalances. The issue is complicated further by the impact of individual variability in dietary habits, medications and comorbidities. In this regard, a personalized medicine approach to individualization of haemodialysate composition offers the best chance of improving patient outcomes. But how can haemodialysate individualization be achieved, and what clinical trial design will best test the impact of such approaches on patient outcomes?