Recruitment of immigrant and ethnic minorities in primary prevention trials of cardiovascular disease

Abstract

Background: The risk of cardiovascular disease (CVD) may differ across ethnic groups, including those who immigrate to Canada, USA and the UK. Accordingly, the absolute and relative benefits of CVD prevention strategies evaluated in randomized clinical trials (RCTs) may differ by the ethnic and immigrant composition of study participants.

Methods: We searched MEDLINE, EMBASE and Cochrane databases for RCTs of primary prevention strategies for CVD, published between 1980 and December 2009. We only included RCTs of a CVD primary prevention strategy comprising at least 100 participants aged >19 years, and those published in English. We abstracted data on study and participant characteristics, interventions and outcomes, as well as a description of the immigrants and ethnic composition of the participants. We also recorded whether a study was stratified by immigrant and/or ethnic subgroups in evaluating the efficacy of the study intervention.

Results: Out of 45 RCTs that met the selection criteria, 11 (24.4%, 95% CI: 14.3-38.8) included and/or reported on the ethnic status of the participants. There were 140,764 persons enrolled in these 11 RCTs, with CVD and/or CVD-related death as the primary outcome, evaluated over a median duration of 5 years. In all 11 trials, the weighted proportion of participants of non-White ethnicity was 10.3% (95% CI: 6.8-15.4). Asian or Asian Pacific ancestry comprised 2.0% (95% CI: 1.1-3.9) of all participants in the five trials that reported details about this group. In no study was the therapeutic efficacy of the intervention was stratified by ethnicity, and none reported on the number of participants who were immigrants.

Conclusion: RCTs of CVD prevention strategies either rarely recruit or rarely report on the ethnic and immigrant status of their participants. Evaluation of the relative efficacy of CVD prevention strategies should also consider these criteria.