Improving retrieval of clinical trials in the LILACS database

Article type
Authors
Castro AA, Clark OAC, Atallah AN
Abstract
Introduction: The Cochrane Collaboration has been working to re-tag articles in Medline as RANDOMIZED CONTROLLED TRIAL (RCT) and CONTROLLED CLINICAL TRIALS (CCT). The LILACS database has not previously been systematically searched to identify studies for re-tagging. This is the first effort to improve retrieval from this database.

Objective: To identify RCTs and CCTs in the LILACS database.

Methods: Survey of two independent observers. Sample: The LILACS database (Latin American and Caribbean Health Science Information Database), 30th edition, January 1998, edited by BIREME (Latin American and Caribbean Health Science Information Center). LILACS indexes 670 journals in the region, with abstracts in English, Portuguese or Spanish; only 41 overlap in the MEDLINE-EMBASE. Two authors independently selected the records and any disagreements were resolved in a consensus meeting. The studies were identified to first of three phases of the optimal search strategy (Castro, 1997, from Dickersin, 1994) for the LILACS database. The titles and abstracts of all retrieved records were read and coded as RCT or CCT according to the definition of the National Library of Medicine. Main outcomes measures: The number of retrieved studies RCT and CCT fields as publication type compared to the search strategy.

Results: Applying the search strategy to the entire LILACS database (1985 to 1996), 765 records were found, 244 using publication type RCT and 10 using CCT. The search revealed 351 new records which lacked tags. One hundred thirty-one of these 351 (37%) were RCTs and 220 (63%) were CCTs. The Kappa coefficient of interobserver agreement was 0.81.

Discussion: The indexing of RCTs and CCTs in the LILACS database needs to be improved to aid in their retrieval. Keywords: Clinical Trial. Electronic Databases. Location and Selecting studies. Information Storage. MEDLINE.