Socioeconomic status and inequities in treatment initiation and survival among patients with cancer, 2011-2022

Abstract

Background: Lower neighborhood socioeconomic status (SES) is associated with suboptimal cancer care and reduced survival. Most studies examining cancer inequities across area-level socioeconomic status tend to use less granular or unidimensional measures and pre-date the COVID-19 pandemic. Here, we examined the association of area-level socioeconomic status on real-world treatment initiation and overall survival among adults with 20 common cancers.

Methods: This retrospective cohort study used electronic health record-derived deidentified data (Flatiron Health Research Database, 2011-2022) linked to US Census Bureau data from the American Community Survey (2015-2019). Area-level socioeconomic status quintiles (based on a measure incorporating income, home values, rental costs, poverty, blue-collar employment, unemployment, and education information) were computed from the US population and applied to patients based on their mailing address. Associations were examined using Cox proportional hazards models adjusted for diagnosis year, age, sex, performance status, stage, and cancer type.

Results: This cohort included 291 419 patients (47.7% female; median age = 68 years). Patients from low-SES areas were younger and more likely to be Black (21.9% vs 3.3%) or Latinx (8.4% vs 3.0%) than those in high-SES areas. Living in low-SES areas (vs high) was associated with lower treatment rates (hazard ratio = 0.94 [95% confidence interval = 0.93 to 0.95]) and reduced survival (median real-world overall survival = 21.4 vs 29.5 months, hazard ratio = 1.20 [95% confidence interval = 1.18 to 1.22]). Treatment and survival inequities were observed in 9 and 19 cancer types, respectively. Area-level socioeconomic inequities in treatment and survival remained statistically significant in the COVID-19 era (after March 2020).

Conclusion: To reduce inequities in cancer outcomes, efforts that target marginalized, low-socioeconomic status neighborhoods are necessary.

Figure 1.

Unadjusted Kaplan-Meier estimates of treatment initiation and real-world overall survival, by area-level socioeconomic status among patients receiving care for 20 common cancers. US Census Bureau block group data from the American Community Survey (2015-2019) were used to measure area-level socioeconomic status per the Yost Index (incorporating income, home values, rental costs, poverty, blue-collar worker, unemployment, and education information). Socioeconomic status quintiles were determined from the US population, and then applied to patients based on their latest residential address. The index date was defined as initial, advanced, or metastatic diagnosis (depending on specific cancer diagnosis; see Supplementary Table 2, available online). Patients were followed from index diagnosis until the event of interest (treatment initiation or death), last confirmed activity, or end of the study period (December 2022). SES = socioeconomic status.

Figure 2.

Unadjusted Kaplan-Meier estimates of treatment initiation and real-world overall survival, by area-level socioeconomic status among patients receiving care for 20 common cancers during the COVID-19 pandemic, March 2020 to December 2022. US Census Bureau block group data from the American Community Survey (2015-2019) were used to measure area-level socioeconomic status per the Yost Index (incorporating income, home values, rental costs, poverty, blue-collar worker, unemployment, and education information). Socioeconomic status quintiles were determined from the US population, and then applied to patients based on their latest residential address. The index date was defined as initial, advanced, or metastatic diagnosis (depending on specific cancer diagnosis; see Supplementary Table 2, available online). Patients were followed from index diagnosis until the event of interest (treatment initiation or death), last confirmed activity, or end of the study period (December 2022). SES = socioeconomic status.