ASPO Abstracts
Cardiovascular disease mortality among breast cancer survivors in the US by socioeconomic status and rurality, 2000-2018
Category: Cancer Health Disparities
Conference Year: 2022
Abstract Body:
Purpose: Cardiovascular disease (CVD) mortality among breast cancer survivors may be influenced by county-level socioeconomic status (SES) factors and degree of rurality. Methods: We examined CVD mortality among first primary localized/regional breast cancer survivors (diagnosed between 2000-2017; aged 18-84; survived 12+ months; received initial surgery) in the US 18 Surveillance, Epidemiology, and End Results program, and compared to the general population using standardized mortality ratios (SMRs; observed/expected), adjusted for age, race, and calendar year. Analyses were stratified by stage and quintiles of county-level SES (measured via Yost Index; lowest quintile=low SES, highest quintile=highest SES) and degree of rurality, ascertained from the American Community Survey. We also estimated 10-year cumulative CVD mortality by rurality accounting for competing non-CVD deaths. Results: Of 724,609 breast cancer survivors, 30,005 died of CVD through 2018 (median follow-up=7.5y). There were large differences in CVD SMRs by county-level SES quintiles: for localized cancers, SMR=0.96[95%CI=0.94,0.99] for the lowest vs SMR=0.70[95%CI=0.68,0.72] for the highest SES quintile; for regional stage cancers, SMR=1.21[95%CI=1.16,1.27] for the lowest vs SMR=0.85[95%CI=0.81,0.90] for the highest quintile. There were similar differences by rurality with CVD SMRs: for localized cancers, SMR=0.96[95%CI=0.90,1.02] for most rural counties vs SMR=0.78[95%CI=0.76,0.79] for most urban; for regional stage, rural SMR=1.18[95%CI=1.07,1.30] vs urban SMR=0.96[95%CI=0.94,0.99]. 10-year CVD cumulative mortality estimates for localized cancers were 5.37% [95%CI=5.00,5.76] in the most rural counties and 4.09%[95%CI=4.01,4.18] for urban; for regional cancers: rural 4.70%[95%CI=4.22,5.22] vs. urban 3.32%[95%CI=3.21,3.43], accounting for competing non-CVD deaths. Conclusion: Breast cancer survivors living in counties of higher SES and more urban have lower CVD SMRs than counties of lower SES and higher rurality, and disparities were greater among regional stage. We also observed a >1% absolute CVD mortality risk difference between rural and urban counties. Future studies are needed on the intersection of individual and county-level SES determinants (e.g., resources and access to healthcare).
Keywords: health disparities; cancer survivorship; breast cancer survivors; cardiovascular disease mortality