摘要：Objectives. To measure the impact of different outreach messages on health insurance enrollment among Medicaid-eligible adults. Methods. Between March 2015 and April 2016, we conducted a series of experiments using mail-based outreach that encouraged individuals to enroll in Pennsylvania’s expanded Medicaid program. Recipients were randomized to receive 1 of 4 different messages describing the benefits of health insurance. The primary outcome was the response rate to each letter. Results. We mailed outreach letters to 32 993 adults in Philadelphia. Messages that emphasized the dental benefits of insurance were significantly more likely to result in a response than messages emphasizing the health benefits (odds ratio = 1.33; 95% confidence interval = 1.10, 1.61). Conclusions. Medicaid enrollment outreach messages that emphasized the dental benefits of insurance were more effective than those that emphasized the health-related benefits. Public Health Implications. Although the structure and eligibility of the Medicaid program are likely to change, testing and identifying successful outreach and enrollment strategies remains important. Outreach messages that emphasize dental benefits may be more effective at motivating enrollment among individuals of low socioeconomic status. As of July 2016, more than 72 million US persons were enrolled in Medicaid and the Children’s Health Insurance Program, an increase of 27% compared with before passage of the Patient Protection and Affordable Care Act (ACA). 1 Community-based enrollment specialists have played a key role in helping low-income adults enroll in Medicaid. 2 Despite outreach efforts, approximately 3.3 million eligible adults living in Medicaid expansion states are not enrolled. 3 Many barriers to enrollment exist, including low health insurance literacy and not being aware that one is eligible. 4,5 Despite the uncertain future of the ACA, it is important to develop strategies to conduct outreach and to market health insurance benefits to this difficult-to-reach population. 6 Enrollment in Medicaid is a key step toward improving uptake of preventive health services, reducing household financial stress, improving mental health, and addressing physical health care needs. 7 One model to increase enrollment involves targeted outreach to individuals enrolled in other public benefit programs that may signal eligibility for Medicaid. In Philadelphia, Pennsylvania, Benefits Data Trust (BDT), a nonprofit organization dedicated to increasing access to public benefits, has conducted large-scale mail campaigns to increase enrollment in the Supplemental Nutrition Assistance Program (SNAP), in addition to Medicaid. Individuals are informed of their likely eligibility for a benefit and invited to contact BDT’s benefits hotline to receive eligibility screening and application assistance. As part of new health insurance outreach activities in 2015 to 2016, we tested the effectiveness of different messages to promote enrollment among Medicaid-eligible adults. On the basis of preintervention qualitative interviews, we hypothesized that emphasizing the financial and dental benefits of insurance, both of which are frequently priorities for this population, would be more effective than messages focusing on the health benefits of health insurance. 5 We also hypothesized that social norming (e.g., reporting how many people in the neighborhood are already insured) would increase responses by making enrollment normative. 8 This technique has been successfully used on college campuses to decrease heavy alcohol intake, using a social marketing campaign to normalize lower consumption quantities. 9
