Abstract 4828: Effect of county-level income and rurality on cardiovascular disease mortality among Asian and Pacific Islander breast cancer survivors in the US, 2000-2018
Authors: Ho Katherine L. , Ramin Cody , Shing Jaimie Z. , Taparra Kekoa , Vo Jacqueline B. 
Published: March 2024

Purpose: To examine differences in cardiovascular disease (CVD) mortality by county-level income and rurality for Asian versus Pacific Islander (PI) breast cancer survivors.

Background: Asian and PI individuals experience varying cancer burden, and prior studies have reported disparities in treatment-related CVD mortality among breast cancer survivors by socioeconomic status and race and ethnicity. However, the impact of county-level income and rurality on CVD mortality among Asian and PI breast cancer survivors, separately, are not well described.

Methods: We included 60,184 Non-Hispanic Asian and PI women diagnosed with first primary, invasive breast cancer between 2000-2017 in the U.S. Surveillance, Epidemiology, and End Results program (aged 18-84, survived 12+ months, and received initial surgery). We estimated the hazard ratio (HR) of CVD mortality using Cox proportional hazard models assessing the impact of county-level income (median household income: low = &lt;$75,000; high [ref] = ≥$75,000) and rurality (urban [ref] = metropolitan counties, population ≥ 250,000; rural = nonmetropolitan counties), separately for Asian and PI breast cancer survivors. Models adjusted for continuous age, stage (localized, regional/distant), and year of breast cancer diagnosis (2000-2004, 2005-2009, 2010-2017). We calculated 10-year cumulative CVD mortality for Asian and PI women accounting for competing risks (e.g., non-CVD deaths).

Results: Of 55,602 Asian and 4,582 PI breast cancer survivors, 1,114 Asian and 178 PI women died from CVD through 2018 (median follow-up, Asian = 6.0 years; PI = 5.5 years). PI women had a higher median age at breast cancer diagnosis (57 vs. 55 years) and more advanced stage (37% vs. 33%) than Asian women. Among Asian breast cancer survivors, low county-level income was associated with elevated CVD mortality (HR = 1.17, 95% CI = 1.04, 1.31), but not rurality (HR = 1.20, 95% CI = 0.91, 1.58). For PI breast cancer survivors, there were no significant associations observed for low county-level income (HR = 0.83, 95% CI = 0.60, 1.14) or rurality (HR = 1.11, 95% CI = 0.76, 1.61). At 10 years after breast cancer diagnosis, 1 in 40 Asian women and 1 in 20 PI women died of CVD.

Conclusion: Asian breast cancer survivors living in low-income counties had heightened risk of CVD mortality compared with those living in higher income counties, highlighting potential healthcare access barriers to cancer survivorship care. Although PI women did not experience significant differences in CVD mortality across groups of county-level income and rurality, they had twice as high absolute risk of CVD mortality than Asian women, warranting further investigation. Future studies that disaggregate Asian and PI individuals into more diverse and granular ethnicity groups are needed to understand heterogeneity in breast cancer survivorship outcomes.

Citation Format: Katherine L. Ho, Cody Ramin, Jaimie Z. Shing, Kekoa Taparra, Jacqueline B. Vo. Effect of county-level income and rurality on cardiovascular disease mortality among Asian and Pacific Islander breast cancer survivors in the US, 2000-2018 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4828.