Identifying clinical trials in the medical literature with electronic databases: MEDLINE alone is not enough

The objective of this study was to compare the performance of MEDLINE and E MBASE for the identification of articles regarding controlled clinical tria ls (CCTs) published in English and related to selected topics: rheumatoid a rthritis (RA), osteoporosis (OP), and low back pain (LBP). MEDLINE and EMBA SE were searched for literature published in 1988 and 1994. The initial sel ection of papers was then reviewed to confirm that the articles were about CCTs and to assess the quality of the studies. Selected journals were also hand searched to identify CCTs not retrieved by either database. Overall, 4 111 different references were reviewed (2253 for RA, 978 for OF, and 880 fo r LBP); 3418 (83%) of the papers were in English. EMBASE retrieved 78% more references than MEDLINE (2895 versus 1625). Overall, 1217 (30%) of the pap ers were retrieved by both databases. Two hundred forty-three papers were a bout CCTs. Two-thirds of these were retrieved by both databases, and one-th ird by only one. An additional 16 CCTs not retrieved by either database wer e identified through hand searching. Taking these into account, EMBASE retr ieved 16% more CCTs than MEDLINE (220 versus 188); the EMBASE search identi fied 85% of the CCTs compared to 73% by MEDLINE. No significant differences were observed in the mean quality scores and sample size of the CCTs misse d by MEDLINE compared to those missed by EMBASE. Our findings suggest that the use of MEDLINE alone to identify CCTs is inadequate. The use of two or more databases and hand searching of selected journals are needed to perfor m a comprehensive searches. (C) Elsevier Science Inc. 2000.