Randomized communication nudges to increase primary care engagement among Medicaid enrollees in Maine.

Despite the importance of primary care in disease prevention, few studies have examined behavioral interventions to increase primary care engagement. In partnership with the Maine Department of Health and Human Services, we implemented a randomized mail-based outreach strategy to connect newly enrolled adults in MaineCare Primary Care Case Management with primary care providers. From March 16, 2021, through January 1, 2022, members were randomized to receive either (1) a standard text-heavy outreach packet (control arm) or (2) the standard packet plus 2 visually simplified mailers that emphasized the value and low cost of a primary care check-up and listed a single primary care provider near the enrollee's home (intervention arm). We found that over 12 months of follow-up, the intervention had no significant effects on the rate or number of primary care visits, emergency department visits, or inpatient hospitalizations. We also observed no significant impact on Medicaid enrollment or recommended primary care services, including receipt of flu shots, cholesterol screenings, or mammograms. Results suggest that barriers targeted by the mailers were not primary drivers of primary care engagement, and other strategies are needed to help connect new Medicaid enrollees with primary care.