Investigation of basic versus additional EAST nudge-based reminders for follow-up examination attendance among workers: a quasi-experimental study

Follow-up examinations after abnormal health checkup findings are important for addressing chronic diseases. While Easy-Attractive-Social-Timely (EAST) nudge-based reminders have been used to promote follow-up examination attendance, the appropriate extent of nudge content to include remains unclear. This study investigated the association between basic and additional EAST nudge-based reminders and follow-up examination attendance among workers.

A quasi-experimental study was conducted among workers at a Japanese transportation company who had abnormal findings and did not respond to an initial notification from October 2024 to March 2025. Participants were geographically assigned to either the basic EAST group (n = 210) or the additional EAST group (n = 122). The basic EAST group received mailed reminders incorporating one principal design element corresponding to each EAST component: Easy (e.g., specifying the appropriate medical departments), Attractive (e.g., a four-panel comic), Social (e.g., encouraging commitment), and Timely (e.g., "Final" labeling). The additional EAST group received reminders containing the same elements as those provided to the basic EAST group, together with a photograph of an expert, her professional affiliations, and an explanation of the commitment concept (Attractive and Social).

Attendance at follow-up examinations was higher in the basic EAST group than in the additional EAST group (29.0% versus 18.0%; p = 0.022; adjusted odds ratio = 1.80; 95% confidence interval, 1.11-3.25).

Although positive outcomes were observed for the basic EAST reminder, the nonrandomized allocation and unequal group sizes warrant cautious interpretation of the findings, and further well-designed studies are needed.