The Effects of Social Vulnerability on the Prognosis and Outcomes of Hodgkin's Lymphoma in Adults across the United States

Introduction: Hodgkin's Lymphoma (HL) is a common presentation of lymphoma in the United States, representing 10% of all newly diagnosed lymphomas or around 8540 cases annually. With an estimated 5-year survival of 88%, HL generally follows a more indolent course compared to other hematologic malignancies, necessitating patients with HL receiving longer follow up care. Therefore, social determinants of health (SDoH) have ample opportunity to impact care; individual SDoH factors, such as race or lower socioeconomic status (SES), have already been identified as contributing poorer prognosis. However, SDoH is realistically multifaceted and combining multiple factors of SDoH to assess HL outcomes has not yet been well characterized. Here, we compare aggregated SDoH encapsulated by the social vulnerability index, a tool created by the Centers for Disease Control (CDC) using census data, to determine how SDoH impacts prognosis and outcomes in patients with HL.

Methods: All adult patients with HL as tracked in the Surveillance, Epidemiology, and End Results (SEER) Program were geographically matched to determine social vulnerability using the Social Vulnerability Index (SVI) at the time of diagnosis. Extranodal HL manifestations were excluded as this was a much rarer form with a different presentation. SVI dynamically weights 15 SDoH considerations into 4 themed domains, including SES, minority status & language, household composition & disability, and housing type & transportation, at the census tract, or county level in sparsely populated areas, to provide a percentile rank ranging from 0 (least vulnerable) to 1 (most vulnerable) across the United States. HL patients were grouped into equivalently sized relative-SVI quintiles based on actual SVI scores ranging from lowest to highest vulnerability. Data was analyzed for HL months surveyed and then patients lost to follow up were excluded to assess mortality in HL months survival for the established quintiles as seen in figure 1. Univariate linear regressions were used to determine significance. Similar methodologies and analyses were also conducted for the 4 SVI domains.

Results: Overall, 49366 individuals were identified in SEER (113±105 months), with 17597 of those individuals included in months survival analysis (76±96 months). All groups were statistically significant (P<0.001) with both overall and SVI domains demonstrating decreasing months surveyed or survival with increasing social vulnerability. Additionally, as seen in table 1, a 31.2% decrease in months surveyed and a 48.9% decreased in months survival was noted for overall SVI when comparing the highest vulnerability (most negative SDoH profile) to the lowest vulnerability quintile (most positive SDOH profile). Substantial decreases were also seen in SES (34.3%, 35.2%), minority status & language (13.7%, 21.8%), household composition & disability (15.8%, 18.8%), and housing type & transportation (22.5%, 36.5%) for months surveyed and months survival respectively between the two groups.

Conclusion: Higher overall SVI scores and specific social vulnerability domain scores correlated with statistically decreased months surveyed and months survival in patients with HL. Furthermore, the size of difference noted between high and low vulnerability groups in both categories indicate the substantial role SDoH has in both patient follow up and mortality and may suggest differing impact across various SDoH domains. Despite established management for HL, consequential health disparities are clearly still present affecting multiple avenues of care. With such a large and encompassing data set, greater power and statistical certainty can be generated. This work highlights the need for specific initiatives to target SDoH in HL to bridge the gap in providing equitable treatment for all.

Badawy:Global Blood Therapeutics: Consultancy; Forma Therapeutics: Consultancy; CHIESI Farmaceutici S.p.A: Consultancy; Bristol-Myers Squibb (BMS): Consultancy; Vertex Pharmaceuticals Inc: Consultancy; Sanofi: Consultancy; Bluebird Bio Inc: Consultancy; Pfizer Inc: Research Funding.