Recruitment of asthmatic ethnic minorities into a methacholine research study: factors influencing participation

How to recruit minority participants into research studies has been an issue since 1993, when NIH funding guidelines required minorities to be included as research participants.

The purpose of this analysis was to determine what factors affected recruitment of asthmatic minorities into a large bronchoconstrictor study involving African-Americans, Hispanics/Mexican Americans, Asian/Pacific Islanders, and whites with mild asthma (forced expiratory volume in the first second of expiration > or = 70%).

Ethnic minorities were recruited for 3 years. Recruitment strategies included physician and clinic referrals, newspaper ads, posters in health care settings, asthma databases, and electronic resources.

After 3 years, the total number of referrals was 650, with 50 from medical doctor clinic settings and 600 from all of the other resources. The inclusion/exclusion criteria were clearly listed, but only 64.5% (419/650) of respondents met inclusion criteria. Of these, only 31.9% (134/419) [corrected] met pulmonary function testing criteria. Only 5, or 1% of the 50 medical doctor clinic referrals met inclusion criteria--1 participated. A total of 106, or 82.8%, completed all of the study procedures; for 87.7% of participants this was their first research experience. Hispanics/Mexican Americans accounted for only 14.8% of the total recruitment responses.

We believe our recruitment strategies did encourage ethnic minorities to participate, but the inclusion criteria of a positive methacholine response proved to be a study enrollment barrier.