Moreover, there should be agreement on the standardization of the measurements. Also, the data collection of this parameter had to be feasible from a practical point of view. 

For HD, Kt/V was chosen as CPI with high priority, whereas it was also agreed that concomitant with delivered Kt/V the length of the dialysis session, the frequency of dialysis treatment, and the dialysis modality (e.g. hemodialysis or hemodiafiltration) had to be reported. The method of choice for measurement is equilibrated Kt/V based on the  regional blood flow two-pool kinetic model, as proposed by the European Best Practice Guidelines on dialysis adequacy. The second CPI with high priority was vascular access type. Although the working group did not consider this parameter to be suitable as benchmark, also the dialysis membrane type was given a high priority, mainly for potential research purposes.

CPIs which were considered to be very important, but which received a lower priority were serum albumin (problems with standardisation of measurement, difficult to modify), PNA (difficulty in standardisation), vascular and peritoneal access problems (difficulties in data collection and standardisation), and peritonitis (difficulties in data collection and standardisation).

With regard to suggestions on research, Cecile Couchoud, one of the two co-chairs of the group, developed two protocols. The first focuses on the methods used to calculate Kt/V in the European dialysis centres. The second concerns the practice patterns with regard to  haemodialysis dose given to the patients among European countries. The second protocol also serves to estimate the relation between co-morbidity and dialysis dose and to identify the relative importance of outcome predictors related to treatment adequacy. Questionnaires to the registries and dialysis centres are being prepared. In the future, we aim to study the relation between the adherence to guidelines and outcome.