Should we abandon GFR in the decision to initiate chronic dialysis?

The best time to start chronic dialysis during the course of CKD stage 5 is controversial. The first randomised control trial of dialysis initiation either in early or late CKD stage 5 in adults (IDEAL study), and 3 studies from the two largest paediatric registries, the U.S. Renal Data System (USRDS) and the European Society of Paediatric Nephrology (ESPN) Registry, have now provided us with evidence to guide us in this important decision-making process. The message 'no benefit from early start of dialysis' is the conclusion from all four studies. However, what are the limitations of these studies? Can GFR be assessed at CKD stages 4 and 5? What are the factors used to assess the benefit of early or late start? These issues are discussed in this review.