Abstract Lung cancer is the leading cause of cancer morbidity and mortality in the United States. Annual screening with low-dose computed tomography (LDCT) reduces lung cancer mortality. However, annual adherence to screening is suboptimal. To improve annual adherence to lung cancer screening (LCS), additional patient education beyond shared-decision making is needed to normalize the screening process. Interventions which leverage digital modes of delivery might have broad reach, but only if patients actively engage with messages from clinical providers. Furthermore, there may be disparities in access to digital communication by patient demographics which will need to be addressed to advance health equity through digital technology. The objective of this study was to understand factors associated with engagement with patient portal messaging. This study was nested within a pragmatic clinical trial to test the “Patient Voices Video” relative to usual care to determine if participants opened video intervention communication delivered through the patient portal. The video-based intervention (Patient Voices Video) incorporated patient testimonials to acknowledge LCS receipt, reminds patients they are due in 12 months for next scan, and reassurance to reduce fear of LCS and role of loved ones to support health choices. Study participants were Kaiser Permanente Washington members aged 50-78 years with recent normal LCS scan and were randomized to either Patient Voices Video or usual care. Study analyses were restricted to those assigned to video arm. Participants randomized to the video arm received a web link via a patient portal message 3 weeks after normal scan. We generated descriptive statistics to summarize differences in proportions in pre-specified demographic factors associated with opening the video message in the patient portal among those in the video arm and registered in patient portal (n=614). Overall, 85% of participants opened their patient portal message. Patient factors associated with not opening patient portal message included: current tobacco use (currently smoking 56% in group that did not open portal message vs 42% in group that opened portal message) and race/ethnicity (18% non-White in group that did not open portal message vs 10% in group that opened portal message). A higher proportion (8%) of those in non-metro areas opened portal message compared to 3% not opening message. There were no differences in likelihood of opening the portal message by age, sex, prior LCS experience, or area deprivation. Patient portal messages can be a successful delivery mode for LCS interventions with high utilization, but disparities in reach are still prevalent by race and ethnicity and tobacco status. Citation Format: Anjali Vasavada, Lorella Palazzo, Matthew Triplette, Hongyuan Gao, Melissa Anderson, Casey Luce, Yu-Ru Su, James Ralston, Kristine Rogers, Nadia Bezman, Beverly B Green, Lisa Carter-Bawa, Karen J Wernli. Reach of digital interventions to address disparities in repeat lung cancer screening in Washington State [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr B037.