Outcome expectations and repeated blood donation behavior: a moderated mediation model in a prospective observational study.

Background: Social cognitive theory proposes outcome expectations as an important factor in behavior change and maintenance. However, it is unknown whether and how outcome expectations interact with prosocial traits in predicting repeated blood donation (RBD) behavior.

Purpose: The current study aimed to test the prospective association between outcome expectations and RBD behavior and the roles of altruism and re-donation intention in this association.

Methods: A total of 850 blood donors recruited from blood donation sites in Hangzhou, China, completed an online baseline survey. Their RBD behavior was captured by checking their blood donation records in the database of Blood Center of Zhejiang Province 6 months later.

Results: Anticipated physical benefits positively predicted RBD behavior, while anticipated physical harms negatively predicted it. Moderated mediation analyses showed that overall outcome expectations and anticipated physical benefits predicted more RBD behavior through increased re-donation intention, and this effect was moderated by altruism. Specifically, the positive effect of overall outcome expectations and anticipated physical benefits on re-donation intention was stronger among donors with lower levels of altruism. Overall outcome expectations and anticipated physical benefits were found to have a significant impact on RBD behavior only in donors with lower levels of altruism.

Conclusions: The findings suggest that interventions aimed at promoting RBD behavior should seek to enhance re-donation intention, overall outcome expectations, and altruism. In particular, it is important to increase the overall outcome expectations-especially anticipated physical benefits-of donors with lower levels of altruism.