Because there are no databases of health intervention trials, we conducted a comprehensive literature search of published trials. Using PubMed (http://www.ncbi.nlm.nih.gov/entrez/), we searched 30 unique combinations of terms and strings of terms related to enrollment, refusal, race, and ethnicity in phase I trials, phase I/II trials, phase II trials, and randomized controlled trials (see Table S1 for search terms). Studies were eligible for inclusion if they documented the race or ethnicity of eligible individuals invited to enroll, as well as the race or ethnicity of those who actually enrolled.
