The Lumbees of south central North Carolina -- the second largest Native American tribe east of the Mississippi River -- have a significantly higher burden of cardiovascular risk factors than do similar non-Lumbees, according to a new analysis by Duke Clinical Research Institute researchers. They said their findings exemplify the need to identify specific groups most vulnerable to heart disease, so that appropriate health care resources can be marshaled to help them.
While the researchers found that the Lumbees who came to the hospital for heart treatment had significantly higher rates of such risk factors as diabetes, hypertension and prior history of coronary artery disease and heart attack, they also tended to be younger and more likely to be female. They were also more likely to receive angioplasty during their hospitalization than non-Lumbees, found the researchers.
Furthermore, nine years after the initial hospitalization, the Lumbees had similar mortality rates as non-Lumbees, yet they were more likely to have suffered from at least one non-fatal heart attack during that time. The Lumbees also had lower rates of heart procedures – whether angioplasty or coronary artery bypass surgery – to re-open clogged coronary arteries during that nine-year period.
The researchers said that the sometimes mixed findings should not only spur more research into how Lumbees can receive improved care after having been diagnosed with heart disease, but also on strategies for improving primary prevention measures to forestall heart disease in the first place.
"With health care and heart care costs rising in the U.S., it is very important to identify groups of patients who are at the greatest risk in order to develop strategies to help them," said Druenell Linton, M.D., Duke internal medicine resident who presented the results of the Duke study March 12, 2006, during the 55th annual scientific sessions of the American College of Cardiology in Atlanta.
"Identifying those groups, like we have in this study, marks a first step in this process of improving health care outcomes and addressing disparities in health care," Linton continued. "In order to improve delivery of, or access to, health care, it is important to first show the need. It would appear from our data that the Lumbees may have more severe disease compared to the general population."
It is estimated that there are more than 50,000 Lumbees, living primarily in the Robeson County area of North Carolina. While previous studies have shown that Native Americans in general have greater rates of cardiovascular disease, little research has been conducted about the incidence of heart disease and risk factors in the Lumbee population.
"Native Americans have a lot more cardiovascular disease than the population in general, but what we don't know is how much of their increased risk is due to their genetic background and how that background is modified by Western lifestyles and environmental factors," said Duke cardiologist Kristin Newby, M.D., senior member of the research team.
"As a clinician who takes care of many Lumbees, I think the findings from this analysis are truly impressive, particularly the findings that they tend to be younger and more likely female," Newby continued. "These results raise important questions that will need to be addressed."
For the study, the investigators consulted the Duke Databank for Cardiovascular Disease, which has been collecting data on patients who have received a heart procedure at Duke since 1969. The researchers identified 920 Lumbees who had received a cardiac catheterization. From the same databank, the researchers identified 2,763 random non-Lumbees to serve as a comparison.
The researchers found statistically significant differences between Lumbees and non-Lumbees in age (60 vs. 64), hypertension (70.9 percent vs. 62.5 percent), diabetes (37.6 percent vs. 28.1 percent), prior heart attack (60.6 percent vs. 49.9 percent) family history of heart disease (51.7 percent vs. 38.8 percent) and obesity (29 percent vs. 27.5 percent).
"What we found particularly interesting was that when they came to the hospital, the Lumbees tended to be younger than non-Lumbees; however they presented with a higher incidence of a prior heart attack or prior heart revascularization procedure," Linton said. Specifically, 16 percent of Lumbees had already had an angioplasty procedure, compared to 6.5 percent for non-Lumbees.
Another interesting finding deals with the drugs known to reduce the risks of future events that are prescribed to heart patients after discharge from the hospital. Within 30 days of catheterization, fewer Lumbees were taking statins (19.8 percent vs. 24.7 percent), ACE inhibitors (13 percent vs. 15.5 percent), beta blockers (40.6 percent vs. 46.9 percent) and aspirin (67.6 percent vs. 74.3 percent).
The Duke team, led by Svati Shah, M.D., is also currently investigating the genetic characteristics of cardiovascular disease in the Lumbees. Since Duke has been collecting genetic material on all patients who receive a catheterization at Duke, the team hopes to correlate genetic information with clinical characteristics and subsequent outcomes.
Other members of the Duke team were Adrian Hernandez, M.D., and Robert Tuttle.
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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