This variety also reflects their differences in management. Whereas some registries are entirely neglected by their regional governments and are still run by motivated clinicians who devote part of their time to gather information from other colleagues, most registries are run by professionals working for their governments and under the supervision of registry committees composed by nephrologists. A few registries are mandatory but most remain voluntary, although usually the response rates are quite high. In the last years we can notice how increasingly involved the health authorities have become, once they are finally aware of the need to measure and know the burden of treating chronic renal disease that they are going to finance.

To coordinate these registries the Group of Registries of Renal Patients (GRER, in Spanish) was created in 1998 on an initiative of the Spanish Society of Nephrology, and it is currently composed of twelve registries and a representation of the Spanish Society of Nephrology whereas the five autonomous communities still without registry are invited as observers. The immediate objective of GRER has been to expand registries to all communities and its long-term objective is to establish a Spanish confederation of dialysis and transplantation registries. Meanwhile, the coordination has given rise to collaboration in seven annual reports of the epidemiology of chronic renal disease in Spain and to co-operatively address pieces of research. A document on harmonization of criteria has been agreed on and new proposals to extent unified criteria and set procedures dealing with patients transfers between autonomous communities are being discussed. An evaluation to set standards that could lead to quality control is about to take place. In this process, the wide experience of the developed registries proves invaluable to the new ones.