Outreach to new mothers through direct mail and email: recruitment in the Early Check research study.

Meeting recruitment targets for clinical trials and health research studies is a notable challenge. Unsuccessful efforts to recruit participants from traditionally underserved populations can limit who benefits from scientific discovery, thus perpetuating inequities in health outcomes and access to care. In this study, we evaluated direct mail and email outreach campaigns designed to recruit women who gave birth in North Carolina for a statewide research study offering expanded newborn screening for a panel of rare health conditions. Of the 54,887 women who gave birth in North Carolina from September 28, 2018, through March 19, 2019, and were eligible to be included on the study's contact lists, we had access to a mailing address for 97.9% and an email address for 6.3%. Rural women were less likely to have sufficient contact information available, but this amounted to less than a one percentage point difference by urbanicity. Native American women were less likely to have an email address on record; however, we did not find a similar disparity when recruitment using direct-mail letters and postcards was concerned. Although we sent letters and emails in roughly equal proportion by urbanicity and race/ethnicity, we found significant differences in enrollment across demographic subgroups. Controlling for race/ethnicity and urbanicity, we found that direct-mail letters and emails were effective recruitment methods. The enrollment rate among women who were sent a recruitment letter was 4.1%, and this rate increased to 5.0% among women who were also sent an email invitation. Study Highlights WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC? Under-representation by traditionally underserved populations in clinical trials and health research is a challenge that may in part reflect inequitable opportunities to participate. WHAT QUESTION DID THIS STUDY ADDRESS? Are direct-mail and email outreach strategies effective for reaching and recruiting women from traditionally underserved and rural populations to participate in large-scale, population-based research? WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE? Despite sending recruitment letters and email invitations in roughly equal proportion by urbanicity and race/ethnicity, women living in rural areas were less likely to enroll (2.8%) than women from urban areas (4.2%). Additionally, enrollment rates decreased as the probability that women were members of a racial or ethnic minority group increased. HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE? Results from this study might encourage researchers to take a holistic and participant-centered view of barriers to study enrollment that may disproportionately affect underserved communities, including differences in willingness to participate, trust, and access to resources needed for uptake.