George Howard, DrPH
Professor/Chairman
Department of Biostatistics
The University of Alabama at Birmingham
Birmingham, Alabama

In accordance with the Accreditation Council for Continuing Medical Education Standards for Commercial Support, Dr. Howard has no conflicts of interest of report.

The University of Alabama School of Medicine is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.

The University of Alabama School of Medicine designates this educational activity for a maximum of 0.25 Category 1 credit toward the AMA Physician's Recognition Award. Each physician should claim only those hours of credit that he/she actually spent in the activity.

The boards of nursing in many states, including Alabama, recognize Category 1 continuing medical education courses as acceptable activities for the renewal of license to practice nursing.

Comparing Criteria

Researchers analyzed stroke death data reported from 1997 to 2001 and calculated mortality rates by race and age. Findings in Southern states were compared with non-Southern states with large African American populations, including California, Illinois, Indiana, Maryland, Michigan, New Jersey, New York, Ohio, and Pennsylvania. From ages 45 to 65 years, African American men are at greater risk from stroke death, although racial differences decrease at older ages, with no apparent disparities after age 85 years.

Stroke death rates vary considerably from state to state, as Howard and colleagues noted in a related presentation at the American Stroke Association's International Stroke Conference in February 2005. In New York, the risk of death from stroke among whites aged 55 to 64 years was 0.32 per 1000 versus 0.68 per 1000 among African Americans in the same age group. In South Carolina, the stroke death rate for whites aged 55 to 64 years was 0.5 per 1000 versus 1.95 per 1000 for same-aged African Americans. "In short, African Americans in New York are twice as likely to die from stroke than whites, but in South Carolina, their risk is 3.8 times greater," Howard explains.

The REGARDS study is in the process of evaluating 30,000 community-dwelling volunteers to define contributors to racial and geographic disparities in stroke mortality. A report on the first 11,000 study participants also was presented at the February stroke conference.

"Some researchers initially presumed disparities in the stroke belt were partly the result of lack of the population's education about hypertension; that Southerners were less aware of hypertension or that Southern clinicians were less likely to prescribe hypertension medications," Howard says. "In fact, the REGARDS study has shown Southern physicians are equal or better at prescribing medications for hypertension, and African Americans in the South are largely aware of the importance of being tested for the disease."

The contribution of blood pressure control to racial mortality disparities does not appear to be due to a lack of education or medication, Howard says, but perhaps control of hypertension is key. "We need to explore if hypertensive medications are equally effective in both races and if monitoring is similar, because data show African Americans on hypertensive medications are 40% less likely than whites to have their blood pressure controlled."

Hypertension remains the leading risk factor for stroke, but REGARDS study findings indicate adequately treating hypertension alone is unlikely to erase the geographic disparity among stroke deaths. "While controlling hypertension remains critical in stroke prevention, the causes for geographic and racial disparities require exploring other traditional risk factors, such as diabetes and smoking, but also nontraditional risk factors, such as underlying inflammation or infections, he says.

Recruiting continues for the REGARDS study to complete the cohort of 30,000 participants aged 45 years and older, using a combination of mail and telephone surveys to collect demographic information and medical histories. An external management service of nearly 7000 health professionals throughout the country collect height, weight, waist measurement, blood pressure, electrocardiogram readings, and blood and urine samples at a patient's home, workplace, or other convenient site. Every effort is made to obtain information quickly and with minimal discomfort, Howard notes. After the initial visit, patients receive follow-up telephone calls every 6 months.

Samples are handled in accordance with a strict standardized protocol at the University of Vermont College of Medicine, where REGARDS study co-medical director Mary Cushman, MSc, MD, oversees the laboratory.

"Although African Americans are more likely to die from stroke, particularly between ages 45 and 65, contributing risk factors for stroke, such as hypertension and diabetes, account for only 30% to 40% of the rate of excess mortality among African Americans," Howard says. "We must have more data to explain this anomaly, and our current geographic findings are an excellent start. While the data should in no way suggest treating hypertension is of lessened critical importance, it does indicate the methods we are using to control hypertension in this high-risk group are not as effective as we would like."

However, experts agree that using race to determine prescription preferences is less than desirable. Potentially, results from REGARDS and other large-scale inclusive clinical trials will shed light on the most effective treatment modalities for conditions that disproportionately affect minorities.

The REGARDS study is expected to conclude in 2007, although preliminary data such as the compelling findings about disparities in stroke mortality among different racial groups and geographic areas, will continue to be released to promote collaboration among clinicians, scientists, biostatisticians, and epidemiologists. These data will be used to address hypotheses currently proposed as contributors for racial and geographic disparities in stroke mortality risk, including differences in traditional risk factors, lifestyle, smoking habits, genetic factors, socioeconomic status, access to care, and risk-factor management.

"Ultimately, our goal is to translate findings from the REGARDS study to information that can be used to guide interventions to reduce the burden of stroke. Once we understand the causes for the differences in stroke mortality, we can take steps to correct them and save lives," Howard concludes.

For more information:

Dr. George Howard
1-800-UAB-MIST
mist@uabmc.edu

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