In this scenario some registries are evolving in organizations providing not only basic epidemiologic analyses but also wide ranging opportunities for research to members. This is important because clinical research is often restricted to few interested investigators due to the limited access to large databases and due to cost factors. The USRDS is a good example of how the scope of registry research may be widened and how research on clinical epidemiology of renal diseases may be made opened to expert investigators. The fact that renal units in the USA are legally obliged to provide data to the USRDS system is undoubtedly a strong backbone for that registry.

The ERA-EDTA registry has been established on the basis of national registries, most of which are generous initiatives of renal physicians who rely on volunteerism. Volunteerism is a richness but also an objective obstacle for the ERA-EDTA registry evolving into a reliable and articulated database. Yet the fact that many renal units in Europe have adopted computerised clinical files offers an opportunity for circumventing the problem in the future. Carefully compiled clinical files have the potential to bring research closer to practice and audit. The advantages of these databases include wide ownership and high generalisability through the participation of many clinicians, low cost, the possibility to generate large samples, the opportunity to study rare conditions or interventions and the provision of accurate information for clinical practice and audit. There is growing interest in high quality clinical files and clinicians are combining efforts in order to standardise the collection of clinical information. Presently the task appears tantalising but the effort is worth making because the huge cost of clinical knowledge based on clinical trials and powerful clinical data analyses is now an objective limitation to the growth of renal medicine. Exploring the possibility of setting up high quality clinical databases on renal diseases is part of the new mission of our registry. Drs Kramar and van Dijk have started a survey on the use of computerised data files in European countries. The ultimate goal is to use this information for promoting the construction of high quality clinical databases. The creation of such databases represents a tremendous opportunity for European renal physicians in order to establish work groups in diverse clinical research areas to face innumerable unanswered questions and to foster clinical knowledge on renal diseases.