Therefore, we plan to start a study to investigate (1) to what extent the differences in patient survival on RRT between European countries can be explained by differences in residual renal function at the start of RRT in previous years and (2) whether there still are international differences in residual renal function at the start of RRT.
We intend to use the abbreviated MDRD formula to assess residual renal function just before the start of RRT1. The abbreviated MDRD formula includes serum creatinine, age, gender and race. Co-morbidity data will be used to correct the analyses for differences in co-morbidity between countries. Demographic data and the survival follow-up will be taken from the ERA-EDTA Registry database. As this database does not include data on residual renal function and is lacking co-morbidity data in most countries, we are currently exploring which national and/or regional renal registries are able, and willing, to participate in this study. If those national or regional registries do not have data on residual renal function, the ERA-EDTA Registry may assist in data collection by preparing mini-questionnaires for each patient so that the centres can provide us with the data needed.
Up to now, several registries have responded favourably and expressed their willingness to participate. After further exploration we will decide together with the national and regional registries on the feasibility and scale of data collection within their coverage area.
1DOQI guideline: http://www.kidney.org/professionals/doqi/kdoqi/p5_lab_g4.htm

Vianda Stel
Epidemiologist and member of the ERA-EDTA Registry staff