[Disease registries in the epidemiological researching of rare diseases in Spain].

Background: The use of tools such as disease registries poses a problem in the case of rare diseases. This study is aimed at describing the current situation concerning rare disease registries in Spain.

Methods: The information provided by two Spanish health registries directories prepared by the Spanish Health Assessment Technologies Agencies are employed, a descriptive cross-sectional study being conducted. The registries identified in these directories has been classified as: (1) "Specific rare diseases" (2) "Unspecific but with information on rare disease and (3) "Non-informative regarding rare diseases".

Results: The 2000 directory listed 82 registries, 15.8% of which were classified under Group 1, whilst a total of 107 registries, 16.8% in Group 1, were identified in the 2005 review. The main health registries in Group 2, by topic, were: cancer, mortality, psychiatry and nephrology. No general rare disease registries were found in the directories.

Conclusions: Although few in number, health registries do exist in Spain including information on rare diseases. Areas have been identified by topic lacking registries and also information systems or registries unidentified in the sources used. Continuing efforts must be made to improve the information available on rare diseases.