The impacts of area-level social deprivation on overall survival in patients receiving immune-checkpoint inhibitors (ICI) treatments: A retrospective cohort study.
Authors: Elsaid Mohamed I. , Meara Alexa Simon , Owen Dwight Hall , Shendre Aditi , Li Lang , Doubeni Chyke , Paskett Electra D. 
Published: May 2024

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Background: Despite recent advancements in ICI therapy, disparities in treatment outcomes persist, potentially influenced by social factors. We investigated the association between Area-level social deprivation (ALSD) and overall survival in patients treated with ICIs, aiming to uncover the potential socioeconomic barriers to effective cancer care. Methods: The study included newly diagnosed solid or liquid tumor patients treated with ICIs between 2012 and 2020 at the Ohio State University Comprehensive Cancer Center. Socioeconomic deprivation was defined using the Social Deprivation Index (SDI), a validated measure of disadvantage across small areas using seven components related to demographic and household characteristics. A high ALSD was defined as an SDI score above the sample’s third quartile. Crude and Adjusted Cox proportional models with robust variance to account for group clustering were used to examine the association between overall survival and ALSD. We also examined the relationship between all-cause mortality and each of the seven components of ALSD. Results: A total of 3,317 patients were included in the study with a median age of 62 years, 59.1% males and 89% White non-Hispanics. An estimated 30.7% of patients had lung cancer, 16.3% melanoma, and 10.8% head and neck cancer. Type of cancer was significantly associated with deprivation states (P <0.001). The median (interquartile range) survival time for all participants was 10.3 (3.7–22.3) months. The high ALSD group had 440/800 (55.0%) deaths over 10,999.0 person-years reported, while the low ALSD group had 1275/2517 (50.7%) deaths over 40,994.8 person-years reported – risk ratio of 1.29 (95% CI: 1.15–1.43). High ALSD was significantly associated with a higher risk of all-cause: the crude risk of all-cause mortality was 21% higher for patients in the high vs. low ALSD groups [HR: 1.21; 95% CI: 1.08–1.36]. In the fully adjusted models, high ALSD was associated with an 18% higher risk of all-cause mortality [adjusted HR: 1.18; 95% CI: 1.06–1.33] compared to low ALSD. In a sub-analysis, we limited our cohort to patients undergoing immunotherapy as first-line treatment, and low ALSD remained a significant predictor of increased risk of all-cause mortality. Area-level poverty and residing in areas with higher percentages of rented housing were the main drivers of the increased risk of all-cause mortality in patients residing in high ALSD areas. Conclusions: Patients from areas with higher levels of social deprivation had a significantly higher risk of all-cause mortality compared with their counterparts in less deprived areas. Addressing adverse social factors could expand the benefits of ICIs for everyone and help reduce disparities in cancer care. Future strategies should consider social interventions to advance equitable healthcare outcomes for all cancer patients.