Black Residents of Historically Redlined Areas Have Increased Heart Failure Risk

Older Black Americans living in zip codes that were heavily redlined in the 1930s have a significantly elevated risk of heart failure compared with Black Americans residing in other areas, even after adjusting for demographic, health and social deprivation factors. That’s the conclusion of a new Cleveland Clinic-led study (Circulation. 2023;148[3]:210-219) based on data from more than 2 million Medicare beneficiaries between 2014 and 2019.

“This study adds evidence of adverse cardiovascular outcomes associated with structural racism and highlights the impact of social determinants of health,” says the study’s lead and corresponding author, Amgad Mentias, MD, MS, a cardiologist with Cleveland Clinic. “Significant health effects were demonstrated even many years after discriminatory policies officially ended.”

What was redlining?

In the 1930s, the U.S. government’s Home Owners’ Loan Corporation color-mapped neighborhoods according to estimated riskiness of mortgage loans: areas colored in red had higher proportions of Black residents and were classified as perilous for investment. The effect of such practices not only impacted the ability of residents to obtain homes, credit and insurance, but discouraged investment of all kinds in the resulting “redlined” neighborhoods, exacerbating socioeconomic disparities between Black Americans and others.

The Fair Housing Act of 1968 and the Equal Credit Opportunity Act of 1974 were passed to fight redlining practices, and these efforts were bolstered by several lawsuits that ensued. However, many impacts of discriminatory redlining practices are still evident in the affected neighborhoods today, including shorter life expectancy for residents and worse cardiovascular health.

Heart failure and race

It is well established that heart failure disproportionately affects Black Americans compared with their white counterparts, as it tends to develop earlier in Black Americans and results in more frequent hospitalizations. What accounts for this disparity is unclear, however. It has been hypothesized that differential access to health care is to blame, along with exposure to heart failure risk factors and other social determinants of health.

“We undertook the current study to determine whether structural discrimination ― as manifest by redlining ― could be identified as an independent contributory factor,” explains co-author Milind Desai, MD, MBA, Vice Chair for Education in Cleveland Clinic’s Heart, Vascular & Thoracic Institute.

Data sources and study design

The researchers obtained redlining information from the Mapping Inequality Project, which uses data from the National Archives and Records Administration and contains records of the Home Owners’ Loan Corporation from 1935 to 1940.

The study group classified neighborhoods by the proportion of redlined areas in each zip code, with residents living in the most heavily redlined zip codes (quartile 4) compared to those living in quartiles 1 to 3 combined and in non-redlined areas. Black and white residents were separately analyzed.

The study cohort included 2,388,955 Medicare beneficiaries between 2014 and 2019 with available zip codes, consisting of 801,452 Black beneficiaries and 1,587,503 white beneficiaries. More than 1,000 zip codes with redlining data were used in the analysis.

Medicare data included demographic and health factors, as well as hospital admissions for heart failure during the study period, which was the primary outcome of interest.

The study also used 2015 to 2019 data from the Social Deprivation Index (SDI) to analyze the impact of social determinants of health. Organized by zip code, the SDI is scored from 0 to 100 and incorporates seven factors reflecting poverty, education, employment, housing and family stability.

Study findings

In this study, 27.7% of Black Medicare beneficiaries lived in redlined zip codes versus 15.8% of white beneficiaries (members of other racial groups did not have sufficient data for analysis). Key findings included the following:

• After adjusting for age, sex and comorbidities, the risk of heart failure was significantly higher among Black residents in zip codes with a higher redlining proportion (quartile 4 vs. quartiles 1-3) (risk ratio [RR] = 1.08 [95% CI, 1.04-1.12], P < 0.001).
• No such effect was seen for white Medicare beneficiaries, with less risk of heart failure in those living in more heavily redlined zip codes after adjusting for age, sex and comorbidities (RR = 0.94 [95% CI, 0.89-0.99], P = 0.02).
• Among Black beneficiaries, a significant interaction was present between proportion of redlining and SDI score, with increased redlining significantly associated with heart failure risk solely in socioeconomically distressed areas.

Health effects of historical discrimination linger

The researchers conclude that Black Americans living in historically redlined areas have an increased risk of heart failure, even after adjusting for contemporary adverse social determinants of health ― the main driver of increased risk ― as well as demographics and comorbidities. “This points to the role of structural racism in disparities of cardiovascular health,” notes Dr. Mentias.

“This analysis underscores the need for targeted public health interventions in poor neighborhoods,” he adds. “In addition, public policies aimed at fostering investment in such areas would make them better places to live ― and likely reap health benefits for residents.”

“These findings remind us that identifying and tackling systemic issues like redlining, which impact healthcare and longevity, remain a crucial responsibility up to the present day,” concludes Dr. Desai.