Department of Research & Evaluation News

PASADENA, Calif. — People who are African-American, American Indian/native Alaskan, Asian, or native Hawaiian and other Pacific Islanders have a significantly greater chance of developing hypertension than people who are white or Hispanic who are in the same weight category or live in neighborhoods with similar education levels.

The Kaiser Permanente study, which included more than 4 million people across the United States, was published today in the Journal of Clinical Hypertension.

“This research shines new light on how pervasive the racial/ethnic disparities are in hypertension, and that the prevalence of hypertension among American Indians, native Hawaiians and Asians is nearly as high as that of African-Americans,” said the study’s lead author, Deborah Rohm Young, PhD, of the Kaiser Permanente Southern California Department of Research & Evaluation.

“Results from this study may provide information that could lead to better targeting of interventions to reduce hypertension, not only by race/ethnicity but possibly by weight category or social economic status.”

Hypertension is one of the most important modifiable risk factors for cardiovascular disease and stroke, and racial and ethnic disparities in hypertension have been well documented. This research adds to our understanding of how weight and social economic status — as measured by neighborhood education level — are associated with the prevalence of hypertension among non-white racial and ethnic groups, compared to whites.

The goal of this study was to examine the prevalence of hypertension in a large ethnically and regionally diverse cohort of overweight and obese adults to determine whether prevalence of hypertension varied by body mass index and neighborhood education categories. Researchers analyzed the electronic health records of 4,060,585 overweight or obese adults from the Patient Outcomes Research to Advance Learning network, which includes Kaiser Permanente patients in California, Colorado, the District of Columbia, Georgia, Hawaii, Maryland, Oregon, Virginia and Washington; HealthPartners patients in Minnesota and Wisconsin; and Denver Health patients in Colorado.

Approximately half of the patients were white, about 25% were Hispanic, 13% were Asian,11% were African-American, 1.5% were native Hawaiian/other Pacific Islander, and 0.6% were American Indian/native Alaskan.

Researchers found that among this group of overweight or obese adults, 36.9% had a diagnosis of hypertension.

The age-standardized prevalence of hypertension was:

• 46.0% among African-Americans
• 44.7% among Native Hawaiians and other Pacific Islanders
• 40.4% among Asians
• 37.3% among American Indian/native Alaskans
• 34.9% among whites
• 34.3% among Hispanics
• Also, the differences in hypertension prevalence between whites and other race/ethnicities did not substantially differ by neighborhood education level.

Patients were categorized as overweight or obese class 1, 2 or 3, based on body mass index (or BMI), which is weight divided by height squared. For example, a 5-foot, 4-inch person who weighed 155 pounds was in the overweight category, and at 210 pounds was in the obese class 2 category.

Researchers found that hypertension prevalence was 5 to 10% higher at each successive increase in overweight or obese weight category for all races and ethnicities.

“We see from the results of this research that maintaining a lower weight remains a key factor in preventing hypertension regardless of race and ethnicity,” said Michael A. Horberg, MD, executive director of Research and Community Benefit and Medicaid for the Mid-Atlantic Permanente Medical Group and the executive director of the Mid-Atlantic Permanente Research Institute.

“But other factors are also at work, and more research needs to be conducted to discover the many factors that may contribute to hypertension prevalence across racial/ethnic groups.”

In addition to Young and Dr. Horberg, authors on this study were Heidi Fischer, PhD, Kaiser Permanente Southern California Department of Research & Evaluation, Pasadena, Calif.; David Arterburn, MD, Kaiser Permanente Washington Health Research Institute, Seattle; Daniel Bessesen, MD, Denver Health, Denver; Lee Cromwell, MS, Kaiser Permanente Georgia, Atlanta; Matthew F. Daley, MD, Kaiser Permanente Colorado, Institute for Health Research, Denver; Jay Desai, PhD, HealthPartners Institute for Education and Research, Bloomington, Minn.; Assiamira Ferrara MD, PhD, Kaiser Permanente Northern California, Division of Research, Oakland, Calif.; Stephanie L. Fitzpatrick, PhD, Kaiser Permanente Northwest, Center for Health Research, Portland, Ore.; Corinna Koebnick, MSc, PhD and Claudia L. Nau, PhD, of the Kaiser Permanente Southern California, Department of Research & Evaluation; Caryn Oshiro, PhD, and Beth Waitzfelder, PhD, Kaiser Permanente Hawaii, Center for Health Research, Honolulu; and Ayae Yamamoto, ScM, Kaiser Permanente Southern California, Department of Research & Evaluation.

About the Kaiser Permanente Southern California Department of Research & Evaluation

The Department of Research & Evaluation conducts high-quality, innovative research into disease etiology, prevention, treatment and care delivery. Investigators conduct epidemiologic research, health services research, biostatistics research, and behavioral research as well as clinical trials. Major areas of study include chronic disease, infectious disease, cancer, drug safety and effectiveness, and maternal and child health. Headquartered in Pasadena, California, the department focuses on translating research to practice quickly to benefit the health and lives of Kaiser Permanente Southern California members and the general public. Visit kp.org/research. 

About Kaiser Permanente
Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, Kaiser Permanente has a mission to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve more than 11.7 million members in eight states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal Permanente Medical Group physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to: kp.org/share.