Article In Brief
System-level factors largely contribute to racial disparities in the use of carotid revascularization, a study suggests. The researchers found that the odds of undergoing carotid revascularization after stroke was lower in minority- compared to white-serving hospitals.
Patients in hospitals that serve predominantly ethnic minority patients undergo fewer carotid revascularization procedures after stroke than patients in hospitals that serve primarily white patients, according to a new study published online May 17 in Neurology.
Why these disparities exist are not exactly clear. But system-level factors, including the location of the hospital and income level of the patients in the areas served by the hospitals, may be important contributing factors, the study authors said.
Patients in predominantly minority-serving hospitals were 3.6 percent less likely than patients in white hospitals to undergo carotid endarterectomy (CEA)/carotid artery stenting (CAS)—17.6 percent vs. 21.2 percent, respectively, (p<0.001), the researchers reported. And minority hospitals were nearly 20 percent less likely to perform CEA/CAS than white hospitals (OR: 0.81), independent of individual patient race and other measured hospital characteristics such as region, location, size, and annual stroke case volume.
White and Hispanic patients in hospitals that serve predominantly-minority patients also were significantly less likely to undergo CEA/CAS than those in predominantly white-serving hospitals. Although black patients made up the largest minority at both types of hospitals, they had the lowest rates of CEA/CAS.
“While everyone including whites at minority hospitals received fewer of these revascularization procedures, minority patients were affected disproportionately because they typically go to hospitals in the communities where they live,” lead investigator Ronald Faigle, MD, PhD, assistant professor of neurology at Johns Hopkins University School of Medicine in Baltimore told Neurology Today.
Previous studies have shown that overall fewer revascularization procedures are performed in minority patients than whites. “What's new is that we went beyond looking at individual patient level data to investigate the contribution of care location to this disparity,” said Dr. Faigle.
Among the differences the study authors uncovered, for example, patients cared for by minority-serving hospitals were more likely to receive Medicaid and live in a low-income zip code. The researchers surmised that the disadvantaged payer mix and neighborhood income level combined with a paucity of resources to invest in quality-of-care improvement initiatives may have contributed to the disparities in care among minority- and white-serving hospitals.
To investigate these disparities, the researchers looked retrospectively (from 2007-2011) at medical records from the Nationwide Inpatient Sample (NIS), the largest all-payer inpatient database in the country, representing all discharges from a 20 percent stratified sample of non-federal US hospitals. They identified 26,189 ischemic stroke cases due to carotid disease based on ICD9-CM codes, finding data on the use of CEA/CAS in 1,113 white-serving and 325 minority-serving hospitals throughout the United States.
The study authors defined hospitals that treated less than 40 percent minority patients as white-serving hospitals and those that treated more than 40 percent of minority patients as minority-serving hospitals. Predominantly minority-serving hospitals were more likely to be teaching hospitals and located in urban areas and the south than white hospitals, Dr. Faigle noted.
The researchers excluded cases that were electively admitted, enrolled in a clinical trial, or had missing information on key characteristics.
The main study limitation was that the NIS database lacked clinical information on the patients' degree of carotid stenosis which determines the appropriateness of surgery. “The degree of stenosis should be at least 50 percent to justify CEA or CAS in symptomatic patients,” said Dr. Faigle.
Dr. Faigle and his colleagues plan to investigate the specific hospital characteristics driving the differences in CEA/CAS use between minority and white hospitals, including stroke center certification status, financial resources, use of vascular imaging, access to stroke specialists, and availability of necessary equipment.
“There are numerous potential reasons for the system-level factors that cause lower rates of carotid revascularization.”
—DR. AMYTIS TOWFIGHI
Stroke specialists who were not involved with the study weighed in on the system level factors that could drive these disparities in care. “There are numerous potential reasons for the system-level factors that cause lower rates of carotid revascularization,” said Amytis Towfighi, MD, director of neurological services and innovation for Los Angeles County Department of Health Services, in an email, who was not involved in the study.
Potential factors include availability of the operating rooms, angiography suites, anesthesia, endovascular specialists, and surgeons, Dr. Towfighi said. In addition, she added that many of the minority teaching hospitals in urban areas also serve as trauma centers where trauma cases often take priority over urgent or routine procedures such as carotid revascularization.
“The difference in revascularization rates between white and minority hospitals of about 3 percent (in absolute terms) is modest,” Seemant Chaturvedi, MD, FAAN, FAHA, FANA, director of the comprehensive stroke program and vice-chair for strategic operations of the department of neurology at the University of Maryland School of Medicine in Baltimore, told Neurology Today. He said issues related to disease or staffing could underlie the differences in care.
In addition, there may be instances where it is appropriate to not perform revascularization procedures, Dr. Chaturvedi said. “It's important to recognize that some stroke patients with lower socioeconomic status have higher complication rates from CAS/CAE. It's not a benign procedure: 4 to 10 percent of patients who underwent these procedures may experience a stroke, heart attack, or death,” he said.
Dr. Chaturvedi suggested that it may be more appropriate to use a non-surgical approach such as high-potency statins, antihypertensive medication, blood thinners, and diet and exercise counseling. In addition, “some hospitals have established multidisciplinary boards consisting of neurologists and surgeons to identify the best candidates for carotid surgery cases, which some research suggests is a useful tool,” he said.
“These findings are hypothesis-generating but unfortunately don't tell you why there's a difference in revascularization rates,” said Dawn O. Kleindorfer, MD, FAAN, professor and executive vice-chair of neurology and rehabilitation medicine at the University of Cincinnati College of Medicine in Ohio. “We shouldn't assume that discrimination is the only reason for this difference because there may be other explanations. For example, it is possible that ‘white’ hospitals may be doing more surgeries for patients with less severe stenosis that may be unnecessary.”
Dr. Kleindorfer suggested conducting more studies with different datasets “to understand whether or not revascularization procedures are needed and follow national treatment guidelines. Once we better understand the reasons behind this difference, we can begin to address these racial differences,” said Dr. Kleindorfer.
“The secondary finding that white patients in minority hospitals had fewer CAS/CAE procedures than in white hospitals was striking,” said Alejandro Vargas, MD, assistant professor of neurology at Rush University Medical Center in Chicago, IL. “This suggests that organizational structural factors in addition to demographic factors may be involved,” he said.
Prospective data on stroke patients are needed to tease apart the potential influence of other factors on stroke care such as access to comprehensive stroke centers and specialists. “Creating larger registries would facilitate direct one-to-one comparisons with patient groups to determine what those differences are and whether they still exist in 2019,” suggested Dr. Vargas.
A major factor in providing access to stroke specialists is that they are qualified and credentialed to perform revascularization procedures, said Virginia J. Howard, PhD, FAHA, FSCT, professor of epidemiology in the School of Public Health at the University of Alabama in Birmingham.
Dr. Howard has been a co-investigator in the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) involving symptomatic stroke patients and asymptomatic trials including the current CREST-2. “All these trials required specialists to meet extensive criteria including performing a certain number of procedures in the past year and with low complication rates,” said Dr. Howard.
Because not all hospitals have equal resources, a potential systems-level solution is to duplicate what emergency systems in Birmingham and other places are doing, said Dr. Howard. “The hospitals are connected to a central Emergency Medical System (EMS) that enables paramedics to call in when they have a potential stroke patient and ask which hospital is ready with a bed, interventionalist, and/or neurosurgeon to take that patient to. This could eliminate any systemic bias toward minority patients and hospital locations,” said Dr. Howard.
However, it may not eliminate patient preferences. Dr. Howard recalled hearing an EMS call with a potential stroke patient who refused to have the ambulance diverted to a hospital that was better equipped for her condition than her local hospital.
Drs. Faigle, Kleindorfer, Towfighi, Chaturvedi, and Vargas reported no disclosures relevant to the study. Dr. Howard's husband has received consulting fees from Bayer Pharmaceuticals.