Overview of Recruitment Strategies to Reach the Million Milestone and Characterization of the Million Veteran Program Cohort

Background The Department of Veterans Affairs (VA) Million Veteran Program (MVP) began in 2011 with the goal of recruiting at least one million Veterans to participate in a large population genetic and health research program. The Million Milestone Campaign (MMC) was implemented between 2022 and 2023 to reach pre-pandemic recruitment rates and the millionth enrollee by Veterans Day of 2023. The objectives are to describe and evaluate the effectiveness of MMC recruitment strategies and to characterize the cumulative MVP cohort. Methods During the MMC, multiple recruitment strategies, including paper invitation mailings, recruitment calls, mass emails, enroll by mail invitations, and digital marketing, were implemented using a “surround sound” model. Strategy effectiveness was assessed via enrollment rates for each enrollment modality from September 2022 through July 2024. Email and digital media reach were measured by click-through rates and ads viewed. Standard mean differences were used to compare the demographics of enrollees during the MMC with those of enrollees prior, and the cumulative MVP cohort with those of non-MVP VA users. Results More than 6.5 million Veterans were contacted and 109,912 enrolled during the MMC. Enrollment rates from recruitment calls (13.7%) were highest, followed by invitations to enroll by mail (7.8%), email (0.8%), and paper invitations (0.6%). Emails yielded the most enrollments (n = 46,999, 43% of total enrollments), followed by recruitment calls (n = 22,069, 20%), paper invitations (n = 16,062, 14.6%), and invitations to enroll by mail (n = 7,762,7.1%). There were small differences in demographics between those enrolled during the MMC and prior enrollees (n = 906,672); likewise, the cumulative cohort (N = 1,016,584) of largely male participants resembles the non-MVP VA user population. Conclusions In the year leading to the culmination of one million MVP participants, the multi-strategy MMC was effective in recruiting nearly 110,000 Veterans and informing ongoing recruitment. Combined strategies used in a surround sound model of recruitment yielded enrollments that aligned with pre-pandemic rates and accumulated one-tenth the largest cohort of Veterans in VA research history. MVP’s integration within the VHA as a learning health care system, along with linkages to health records and other data sources, is a resource for investigators to improve Veteran health care with precision medicine.