Social vulnerability and clinical trial enrollment: The next frontier of health equity.

1508 Background: Clinical trials are the basis for novel therapies but may not be representative of disadvantaged groups, particularly low-income individuals. This study assesses how social vulnerability impacts enrollment and explores the interaction between race and social vulnerability among patients with the top five leading causes of cancer death. Methods: The national Vizient Clinical Database was queried for outpatients with lung, breast, prostate, colorectal or pancreas cancer from 2022-2023. This includes data from 98% of academic medical centers and more than 110 cancer hospitals. The exposures of interest were Medicaid insurance and social vulnerability as measured by the Vizient Vulnerability Index (VVI), a novel marker of social drivers of health at the census tract level. Participation in a clinical trial was the primary outcome. A multivariable analysis was performed evaluating the association of social vulnerability quartiles with clinical trial participation. Interaction tests were performed for race and VVI. Results: 2,660,566 patients were identified. Of these, 36,456 (1.4%) enrolled in a clinical trial: 28.6% with breast cancer, 26.3% prostate, 22.8% lung, 12.8% colorectal and 9.5% pancreas. Trial participants were more likely to be young, White, privately insured, have metastatic disease, and live in a less vulnerable census tract.5.3% of trial participants were insured by Medicaid (12.2% of Black participants, 8.5% of Asian participants, and 3.5% of White participants), compared to 6.2% of non-participants (p<0.0001).22.6% of participants lived in highly vulnerable neighborhoods (53.5% of Black participants, 19.7% of White participants, and 5.6% of Asian participants), compared to 25.0% of non-participants (p<0.0001). Living in the most vulnerable VVI quartile was associated with decreased odds of clinical trial enrollment (OR 0.86; 95% CI 0.82-0.91, p=0.0442), as was having Medicaid insurance vs. private insurance (OR 0.76; 95% CI 0.73-0.80, p<0.0001). The highest social vulnerability quartiles in the VVI domains for education, neighborhood resources and transportation were associated with decreased enrollment (Table). High social vulnerability decreased the odds of enrollment for Black patients (OR 0.80; 95% CI 0.68-0.88, p<0.0001) more than White patients (OR 0.88; 95% CI 0.89-0.96, p=0.0028); p=0.0054 for interaction. Conclusions: 1.4% of patients in this contemporary, cross-sectional cohort enrolled in a clinical trial. Patients with Medicaid have a 24% lower odds of enrollment than privately insured patients. Neighborhood social vulnerability is also barrier to enrollment, even more so among Black patients. Interventions to address social determinants of health may increase racial diversity in clinical trials. Table: see text