PAD, which affects approximately eight to 12 million Americans and is associated with nearly half of the 150,000 yearly amputations in the U.S., is a potentially life-threatening condition in which the arteries that carry blood from the heart to the legs narrow or become blocked by the buildup of fatty plaque. This can lead to a heart attack, stroke or amputation of the affected limb.

“We discovered that Black patients are nearly 50% less likely to receive vascular interventions to potentially restore the blood flow than white patients, and consequently are at a disproportionately higher risk of a stroke, heart attack or amputation,” said David Armstrong, DPM, PhD, a podiatric surgeon specializing in limb preservation with Keck Medicine and an author of the study. “Additionally, Black patients tend to have more advanced PAD and are sicker at the time of diagnosis, indicating they may not be getting as timely medical attention as their white counterparts.”

PAD often starts out with no or mild symptoms, such as a leg cramp or muscle pain, and therefore often goes underdiagnosed. 

Once detected, generally through a blood test, PAD is typically treated with medication to reduce the plaque in the arteries and through suggested lifestyle changes, such as increased exercise and a healthy diet. If these measures don’t work, physicians usually recommend a procedure known as revascularization. Revascularization either improves the blood flow to the arteries by using a balloon or stent to open them or reroutes the blood to another, healthier artery, which can reduce the risk of a cardiac incident or amputation.

The study discovered that Black patients are more likely to only receive medication and lifestyle change recommendations, while white patients also receive revascularization. “Our findings suggest Black patients are missing out on potentially limb- and life-saving treatments,” said Armstrong. “And because Black patients tend to be sicker at the time of diagnosis than white patients, they may actually be in more need of a revascularization than other patients.”

Armstrong and his colleagues used a large national database to compare rates of diagnostic testing, treatment patterns and outcomes after diagnosis of PAD among commercially insured patients in the United States from the years 2016 to 2021. They identified some 455,000 white patients and 96,000 Black patients. They then compared demographics, markers of disease severity and health care costs as well as patterns of medical management and rates of amputation and cardiovascular events among the two patient groups to reach their conclusions.

While the study did not analyze why disparities in the detection, treatment and outcomes of PAD between Black and white patients exist, one factor may be that Black patients are already at a higher risk of developing PAD, said Armstrong. He also hypothesizes that the inequalities may be due to broader systematic issues in health care such as unconscious bias or barriers to health care access for certain populations.

“We hope this study will encourage physicians to take these differences into account when diagnosing and treating PAD to ensure that vascular interventions are being equally provided to all patients,” he said. “We also urge health professionals to offer more routine screenings for PAD in Black patients.”

Additionally, Armstrong advises patients to proactively seek medical advice and testing if they have any symptoms related to PAD — leg cramping, pain, numbness, weakness or discoloration — and advocate to be considered for all treatment options after diagnosis.

Simple measures such as giving patients pillboxes for their medications, helping patients’ family members understand their medication regimen and having patients attend weekly education sessions about managing the disease through lifestyle changes are all ways that patients could improve medication adherence.

The study also points toward specific challenges that underserved Latinos may be facing. Such challenges include having difficulty understanding what their medications are for, keeping track of their medications and feeling that they may take too many medications. Cohorts in this study took an average of 6.5 prescribed medications daily.

“Obtaining patients’ perspectives is key to finding solutions that help improve their medication adherence and health outcomes,” said Andrea Bañuelos Mota, the study’s first and corresponding author. “Not only do our findings suggest several potential approaches to intervention for Latinos with diabetes, but they could also pave the way for the development of future evidence-based guidelines.” Bañuelos Mota is currently enrolled in the Keck School’s Doctor of Medicine/Master of Public Health (MD/MPH) degree program.

Published in the Journal of General Internal Medicine (JGIM) on June 4, the cross-sectional study involved conducting surveys of 120 patients from across four safety net clinics in Los Angeles. Patients were at least 18 years old, self-identified as Latino/Hispanic/Chicano, were diagnosed with diabetes for more than six months, and were taking multiple diabetes medications. Furthermore, the study’s dependent variable was patients with “controlled diabetes” (i.e., having a hemoglobin A1c level of less than 7.5%) versus patients with “uncontrolled diabetes” (i.e., having a hemoglobin A1c level equal to or greater than 7.5%).

“This study is exemplary of excellent primary care research and brings awareness to the language and literacy barriers faced by our immigrant communities, which health care providers must address to deliver quality medical care,” said Jo Marie Reilly, MD, MPH, professor of clinical family medicine (educational scholar). Reilly leads the Keck School’s Primary Care Initiative, a program created to promote careers in primary care and the one through which this study was established.

Conceived and led entirely by a team of five medical students — including Andrea Bañuelos Mota, Emilio Ernesto Feliz Sala, Jennifer M. Perdomo, Joel Alejandro Solis and Walter M. Solorzano — the study also marks an achievement for the Keck School initiative. “JGIM is one of the highest ranked general internal medicine journals, so it is particularly impressive that a student group got a paper accepted,” said Michael Hochman, MD, MPH, a faculty mentor on the project with Reilly. Hochman is an associate professor of clinical medicine and serves as director of the USC Gehr Family Center for Health Systems Science.

— Elyse Blye

V. Wendy Setiawan (Photo/Ricardo Carrasco III)

“There are very few studies on diabetes and pancreatic cancer that include Latinos and African Americans,” said the study’s lead author V. Wendy Setiawan, PhD, associate professor of preventive medicine at the Keck School. “Both groups have a high rate of diabetes and African Americans, in particular, have a higher risk of developing pancreatic cancer relative to other racial/ethnic groups. Because most people with pancreatic cancer are diagnosed at a late stage, the five-year survival rate is low — about 8 percent. Identifying people who are at high risk early on could potentially save their lives.”

Symptoms of pancreatic cancer typically present when the disease is in its later stages and no screening methods currently exist.

Using prospective data from approximately 49,000 African Americans and Latinos, the researchers found that people who were diagnosed with diabetes between the ages of 65 and 85 were more likely to develop pancreatic cancer within three years as compared with people without diabetes. The data showed that Latinos were four times more likely to develop pancreatic cancer within three years of a diabetes diagnosis, and African Americans were three times more likely.

The research team also looked at whether late-onset diabetes was associated with breast, prostate or colorectal cancer, and no association was found.

“What we found is that, yes, diabetes is associated with pancreatic cancer in African Americans and Latinos, but we also discovered that there is a different type of diabetes here, a late-onset diabetes that’s associated with developing pancreatic cancer within 36 months. The evidence suggests that late-onset diabetes may be an early sign of pancreatic cancer,” Setiawan said.

Late-onset diabetes may be a useful marker for pancreatic cancer, she added, providing an opportunity to screen high-risk groups with new tools such as liquid biopsy, which is a test that looks for cancer cells or DNA from cancer cells in the blood.

“Pancreatic cancer is a rare disease, but if you are diagnosed with late-onset diabetes, have a conversation with your clinician about your individual risk,” Setiawan said. “Early intervention could improve survival.”

— Erica Rheinschild