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

Clinical trials drive novel cancer therapies, yet enrollment remains low and unrepresentative of vulnerable groups. Most clinical trial disparities literature examines demographics, excluding social determinants of health. We evaluated the association between social vulnerability and clinical trial enrollment among patients with the 5 leading causes of cancer death and examined how this association varies by race and ethnicity in the United States.

In this retrospective cohort study, the national Vizient Clinical Database was queried for patients with lung, breast, prostate, colorectal or pancreatic cancer from 2022 to 2023. The exposure was the Vizient Vulnerability Index, a novel, healthcare-specific tool assessing census tract-level social vulnerability. The primary outcome was clinical trial enrollment. Multivariable analysis evaluated the association of Vizient Vulnerability Index with clinical trial enrollment, including tests for interaction by race.

Of 2 660 566 patients, 36 456 (1.4%) enrolled in a clinical trial. Trial participants were more likely to be young, non-Hispanic White, and privately insured and to have metastases. Enrollment odds were lower for patients living in the most vulnerable census tracts (odds ratio [OR] = 0.80, 95% confidence interval [CI] = 0.77 to 0.89) and non-Hispanic Black patients (OR = 0.80, 95% CI = 0.75 to 0.83). Vulnerability in education, transportation, and neighborhood resources was associated with decreased enrollment. High social vulnerability disproportionately impacted enrollment for non-Hispanic Black patients (OR = 0.48, 95% CI = 0.41 to 0.62) compared with non-Hispanic White patients (OR = 0.82, 95% CI = 0.73 to 0.92; P < .0001 for interaction).

Neighborhood social vulnerability is a barrier to cancer clinical trial enrollment, especially among non-Hispanic Black patients. Focused interventions targeting education, transportation, and neighborhood resources may increase equity.