EMBASE versus MEDLINE for family medicine searches: can MEDLINE searches find the forest or a tree?

Objective: Many physicians access electronic databases to obtain up-to-date and reliable medical information. In North America, physicians typically use MEDLINE as their sole electronic database whereas in Europe, physicians typically use EMBASE. While MEDLINE and EMBASE are similar, their coverage of the published literature differs. Searching a single literature database (eg, MEDLINE or EMBASE) has been shown not to yield all available citations, and using two or more databases yields a greater percentage of these available citations. This difference has been demonstrated in a variety of disciplines and in family medicine using the term "family medicine," but differences have not been shown using specific diagnostic terms common in family medicine. We sought to determine whether searching EMBASE with terms for common family medicine diagnoses yields additional references beyond those found by using MEDLINE alone.

Design: Literature search comparison.

Setting: An academic medical centre in the United States.

Interventions: Fifteen family medicine topics were selected based on common diagnoses in US primary care health visits as described in a National Health Care Survey on Ambulatory Care Visits. To promote relevance to family medicine physicians and researchers, the qualifiers "family medicine" and "therapy/therapeutics" were added. These topics were searched in EMBASE and MEDLINE. Searches were executed using Ovid search engine and were limited to the years 1992 to 2003, the English language, and human subjects. Total, duplicated, and unique (ie, nonduplicated) citations were recorded for each search in each database.

Main Outcome Measures: Number of citations for the 15 topics.

Results: EMBASE yielded 2246 (65%) of 3445 total citations, whereas MEDLINE yielded 1199 citations. Of the total citations, only 177 articles were cited in both databases. EMBASE had 2092 unique citations to MEDLINE's 999 unique citations. EMBASE consistently found more unique citations in 14 of the 15 searches (P = .0005).

Conclusion: Overall, EMBASE provides twice as many citations per search as MEDLINE and provides greater coverage of total retrieved citations. More citations do not necessarily mean higher-quality citations. In a comprehensive search specific to family medicine, combined EMBASE and MEDLINE searches could yield more articles than MEDLINE could alone.