Engagement and Retention in Precision Public Health: A Cascade Analysis of Two Cluster Randomized Trials

When research fails to reach and engage all populations who might benefit from study findings, it can compromise scientific validity and ultimately health equity. Few studies have systematically examined factors driving study engagement through longitudinal intervention research. This project examined sociodemographic, geographic, and structural influences on engagement and attrition across the participation "cascade" (outreach, enrollment, retention) for two large-scale multilevel precision medicine and precision prevention trials for smoking and lung cancer screening.

Modified Poisson regression models were used to determine the factors associated with study engagement based on sociodemographic and geographical factors at each step in the cascade of participation, from initial outreach through retention at 12 months post-enrollment. Secondary analyses examined the cascade among the subset of patients who had active electronic patient portals and were approached via the portal.

A total of 24,366 patients were approached for participation. Race, Social Vulnerability Index (SVI), insurance status, and distance from the study site were significantly associated with engagement at various points in the cascade. Black patients were more likely than White patients to be reached (48.9% vs 47.1%; p = 0.022) and to complete eligibility screening (52.8% vs. 38.4%; p < 0.001), but less likely to consent to participate (56.7% vs 69.8%; p < 0.001) and complete genetic testing (58.5% vs. 69.8%; p = 0.003). Patterns of engagement through electronic patient portal versus non-electronic recruitment channels also differed by race- and place-based factors, with Black patients being less likely than White patients to respond in the portal (8.8% vs 15.5%; p < 0.001), and patients who reside farther from the study site being more likely to respond in the portal compared to those who live closer (14.9% vs 12.5%; p < 0.001).

These findings highlight the need for tailored, stage-specific engagement strategies to ensure representative participation in genomic and behavioral intervention research to advance the integration of genomics into public health practice.