To do a systematic review of the literature of the effects of a treatment it is necessary to have a large volume of information available; mostly from randomized controlled trials (RCTs). A search of the electronic databases, such as Medline, does not always allow this type of studies to be identified easily, either because they have been wrongly indexed or because not all journals are included in the database. The Iberoamerican Cochrane Centre has added to the international project of the Cochrane Collaboration to identify clinical trials through handsearching, by developing a register of clinical trials undertaken in Spain.
Methodology: The Catálogo Colectivo de Publicaciones Periódicas en Ciencias de la Salud C-17 was consulted. Each issue of the journals was reviewed by thorough handsearching, following the Cochrane Collaboration critieria for identifying a clinical trial. These criteria are: prospective interventions, comparing two or more treatments, random allocation, human participants. A database was developed in the form of a register, using the reference manager software programme ProCite.
Results: 643 journals edited in Spain were identified and of these, 432 journals (67%) were reviewed. 3,548 clinical trials published in Spain were identified by way of this handsearch. These data have been included in the register of RCTs of the International Cochrane Collaborationn (CENTRAL) and are available in the electronic journal The Cochrane Library.
Conclusions: The handsearch has made searching for clinical trials in a greater nunber of journals possible. Since only 41 of the more than 600 publications in Spanish are indexed in Medline, an exclusively electronic search would have allowed us to find a maximum of 9.5% of the information published in Spain. For this reason we consider that the manual search has added significant results to the information available from clinical trials published in Spanish.
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