Disparities in Cardiovascular Disease-Related Outcomes Among Cancer Survivors in the United States: A Systematic Review of the Literature

Abstract

Background: Cancer and cardiovascular disease (CVD) are major causes of morbidity and mortality in the United States (US). Cancer survivors have increased risks for CVD and CVD-related mortality due to multiple factors including cancer treatment-related cardiotoxicity. Disparities are rooted in differential exposure to risk factors and social determinants of health (SDOH), including systemic racism. This review aimed to assess SDOH's role in disparities, document CVD-related disparities among US cancer survivors, and identify literature gaps for future research.

Methods: Following the Peer Review of Electronic Search Strategies (PRESS) guidelines, MEDLINE, PsycINFO, and Scopus were searched on March 15, 2021, with an update conducted on September 26, 2023. Articles screening was performed using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020, a pre-defined Population, Exposure, Comparison, Outcomes, and Settings (PECOS) framework, and the Rayyan platform. A modified version of the Newcastle-Ottawa Scale was used to assess the risk of bias, and RAW Graphs for alluvial charts. This review is registered with PROSPERO under ID #CRD42021236460.

Results: Out of 7,719 retrieved articles, 24 were included, and discussed diverse SDOH that contribute to CVD-related disparities among cancer survivors. The 24 included studies had a large combined total sample size (n=7,704,645; median=19,707). While various disparities have been investigated, including rural-urban, sex, socioeconomic status, and age, a notable observation is that non-Hispanic Black cancer survivors experience disproportionately adverse CVD outcomes when compared to non-Hispanic White survivors. This underscores historical racism and discrimination against non-Hispanic Black individuals as fundamental drivers of CVD-related disparities.

Conclusions: Stakeholders should work to eliminate the root causes of disparities. Clinicians should increase screening for risk factors that exacerbate CVD-related disparities among cancer survivors. Researchers should prioritise the investigation of systemic factors driving disparities in cancer and CVD and develop innovative interventions to mitigate risk in cancer survivors.

Keywords: Cancer survivors; Cardiovascular disease (CVD); Discrimination; Disparities; Racism; Social determinants of health (SDOH).

Figure 1. Graphical illustration of the PRISMA flowchart detailing the article selection process based on the pre-defined PECOS framework that guided the inclusion and exclusion criteria.

Abbreviations: PECOS, Population, Exposure, Comparison, Comparison, Setting; PRISMA, Preferred Reporting Items for Systematic Review and Meta-Analysis.

Figure 2. Disparities in cardiovascular diseases (CVD) outcomes among cancer survivors in the US.

The first column represents authors and year of each study, the second column represents the US geographical settings of studies, the third column represents different disparities investigated in each statistical test conducted, the fourth column represents CVD-related outcomes investigated, the fifth column represents types of cancer for different study populations, the sixth column represents the reported disadvantaged groups, while the seventh column represents statistical significance reported by studies. This graphical representation shows an overall trend in findings across studies for all statistical tests conducted for specific CVD outcomes investigated. Abbreviations: NHB, non-Hispanic Black; CBD-M, cerebrovascular disease related mortality; HTN-T, hypertension treatment receipt; ASCVD, atherosclerotic cardiovascular disease risk score; CHD-M, coronary heart disease related mortality; HTN-M, hypertension related mortality; BC, breast cancer; HL, Hodgkin Lymphoma, DCIS, ductal carcinoma in situ of the breast; CNS, central nervous system; NHL, non-Hodgkin Lymphoma; hsCRP, high sensitivity C-reactive protein; CAT, cancer-associated thrombosis; HTN-P, hypertension prevalence; LVEF, left ventricular ejection fraction; HNSCC, head and neck squamous cell carcinoma; CRC, colorectal cancer; CC, childhood cancer; SES, socioeconomic status; BGC, breast and gynaecologic cancer; DOA, diseases of the arteries; DOV, diseases of the veins.