Searching a biomedical bibliographic database from Bulgaria: the ABS database

Background: The University of Sofia, Bulgaria, disseminates local biomedical literature (1994 to present) through a free online database, ABS. Objectives: Our objectives were to systematically search ABS, identify citations to controlled trials and discover what proportion of these studies are to be found on MEDLINE. Methods: We searched using Bulgarian and English phrases; manually selected citations of controlled trials and sought these citations on MEDLINE. Results: Using the two languages, we found a total of 628 unique citations, 47 of which seem to be relevant controlled trials (precision 7.48%, 13% of ABS citations were found on MEDLINE). The trials in ABS commonly focused on evaluation of care for people with cardiovascular or urological problems. Discussion: ABS is another source of easily accessed trials not readily available elsewhere.