Historical Redlining Associated with Increased Heart Failure Risk in Black Adults

Shreya Rao, MD, MPH

Credit: American Heart Association

Historical redlining practices are associated with an increased risk of heart failure among Black patients now living in those zip codes, but not their White counterparts, according to a new investigation of ≥2 million adults in the United States.¹

These higher risks of heart failures among these Black patients in redlined zip codes were mainly driven by the increased burden of adverse social determinants of health, highlighting a mechanism of structural racism, and its contributions to continued disparities in cardiovascular health.

In the 1930s, the Home Owners’ Loan Corporation started to sponsor low-interest mortgage loans to help people recover from the financial crisis of the Great Depression. The practice of “redlining” was a color-coding system for neighborhoods across the US, based on “investment risk” criteria: red areas, largely Black communities, were deemed too risky to insure mortgages. The passage of the Fair Housing Act of 1968 outlawed these practices, but reduced investment in social and economic infrastructure led these inequities to continue for multiple generations.

“Although discriminatory housing policies were effectively outlawed nearly a half-century ago, the relationship between historic redlining practices and people’s health today gives us unique insight into how historical policies may still be exerting their effects on the health of many communities,” Shreya Rao, MD, MPH, the study’s co-senior author and a cardiologist and assistant professor in the department of internal medicine at the University of Texas Health Science Center at San Antonio and University Hospital, said in a statement.²

Prior literature has shown a higher rate of stroke and an increased risk of hypertension, type 2 diabetes (T2D), and early mortality due to heart failure among people living in communities exposed to redlining. Across the United States, heart failure affects approximately 6.7 million people in the US and disproportionately impacts Black adults, according to a 2023 statistical update from the AHA. In the current analysis, investigators identified approximately 2.4 million adults in the Medicare Beneficiary Summary Files between 2014 - 2019 with linked residential zip codes.

The study population was 55.4% female, had a mean age of 71 years, and 801,452 participants self-identified as Black adults, and approximately 1.6 million participants self-identified as non-Hispanic White adults. Other races were excluded from the study due to the low amount available within the Medicare data. Exclusions from the analysis were made if participants had a history of heart failure or heart attack in the prior 2 years, had ≤2 years of Medicare coverage before the study start date, or were ≤40 years old.

Maps of historical redlining were overlaid onto modern-day maps of 1,044 zip codes in the US and then sorted by investigators into 4 groups ranging from zip codes with the least amount of area impacted by redlining to those with the greatest area exposed to the practice. Investigators sought to assess the difference in the risk of heart failure between individuals from communities with the highest level of exposure to redlining and those from other communities.

To do so, the team assessed the association between living in higher proportions of redlined zip codes and the risk of heart failure, performing separate analyses for Black and White adults. Variables, including social determinants of health, were determined at the zip-code level with Social Deprivation index scores collected in the American Community Survey from 2011 - 2015. Scores were a composite measured based on 7 demographic characteristics: poverty rate, education level, employment, access to transportation, household characteristics, renters vs. owners, and percentage of overcrowded households.

Upon analysis, investigators found Black adults living in zip codes with higher redlining proportions had an 8% higher risk of developing heart failure after adjusting for age, sex, and comorbidities (risk ratio [RR], 1.08; 95% CI, 1.04 - 1.12; P <.001). Among White adults, redlining was associated with a lower risk of heart failure after adjustment for age, sex, and comorbidities (RR, 0.94; 95% CI, 0.89 - 0.99; P = .02).

A significant interaction was observed between redlining proportion and Social Deprivation Index scores (P interaction <.01). A higher redlining proportion was significantly associated with heart failure risk only among socioeconomically distressed regions. The risk of heart failure was highest among Black adults living in redlined communities with the highest scores on the Social Deprivation Index.

To achieve health equity, the findings suggest the pivotal role of housing as a social determinant of health and could require aggressive enforcement of housing anti-discrimination laws and pathways to homeownership for Black families.

“Decades of discriminatory housing policies have left a lasting imprint on the cardiovascular health of Black communities,” Mitchell Elking, MD, the chief clinical science officer of the American Heart Association, said in a statement.² “This study serves as a stark reminder of the ongoing impact of structural racism and emphasizes the urgent need for restorative actions and targeted investments to promote health equity.”

References

1. Mentias A, Mujahid MS, Sumarsono A, et al. Historical Redlining, Socioeconomic Distress, and Risk of Heart Failure Among Medicare Beneficiaries. Circulation. 2023;148(3):210-219. doi:10.1161/CIRCULATIONAHA.123.064351
2. HeartNews. Redlining linked to higher heart failure risk among black adults in US. EurekAlert! July 17, 2023. Accessed July 19, 2023. https://www.eurekalert.org/news-releases/995421.