Cardiovascular risk in special populations II: hypertension.

Abstract

Racial differences in blood pressure (BP) were reported as early as 1932 when a 7-mm Hg higher systolic BP was recorded in 6000 black workmen compared with 8000 white workmen in New Orleans. Hypertension is of course an important contributor to cardiovascular (CV) events, yet, as of recent surveys, less than one third of the US hypertensive population has adequate BP control despite the availability of a large variety of antihypertensive medications. In fact, hypertension prevalence is increasing, by 3.7% from 1988–1991 to 1999–2000 based on National Health and Nutrition Examination Surveys (NHANES). Although almost 70% of persons were aware of their hypertension in the more recent survey and almost 60% were treated (an increase of 6% from the earlier survey), hypertension was controlled in only 31% (an increase of slightly more than 6%). In terms of special populations, women, the elderly (older than 60 years), and Mexican Americans had lower rates of control than men, younger persons, and non-Hispanic whites. A more recent sampling comparison using expanded sample sizes of NHANES (1998–1994 vs 1999–2002) provided further information in regard to race-specific data on hypertension comparing blacks with whites. The prevalence of hypertension was highest in blacks, increasing from 36% in the earlier NHANES to 41% in the later one (and from 24% to 29% among whites) (Table I). However, awareness of their hypertension status was higher in blacks (78% vs 70%), with an increase of 4% for blacks since the earlier survey without a change in whites. Treatment increased in blacks from 58% to 68%. Although BP control in blacks increased from 23% to 32% since the earlier survey, it remained below whites in both surveys, with 35% of whites having BP control in the latter survey (Table II). In the 1999–2004 NHANES, the prevalence of hypertension increased with age, from 7.3% in persons 18 to 39 years, to 66.3% in persons 60 years and older. The BP control rate (to <140 ⁄90 mm Hg) increased from 29.2% in 1999–2000 to 36.8% in 2003–2004. This increase was significant in sexes, blacks, and Mexican Americans. In the Multi-Ethnic Study of Atherosclerosis (MESA) involving 6814 adults without clinical heart disease, the prevalence of hypertension or selfreported treatment of hypertension was significantly higher in blacks than whites (60% vs 38%) (Figure 1). After adjustment for age, body mass index (BMI), presence of diabetes, and smoking, black race as well as Chinese ethnicity were associated with higher prevalence of hypertension compared with white race, and socioeconomic factors were significantly associated with treated but uncontrolled hypertension in blacks compared with other racial groups. In a study of adherence to guidelines, in this case the Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI) guidelines (1997), a review of medical records of 15,768 visits to 12 internal medicine clinics in 2001–2002 revealed a greater physician adherence among blacks (84%) and Hispanics (83%) than whites (78%) (P<.001). On the other hand, BP was controlled most among whites (39%) vs 35% for blacks and 33% for Hispanics (P<.001). However, in all groups, intensification of therapy led to better control of BP, although Hispanics were less likely than blacks and non-Hispanic whites to have BP therapy intensified. In different regions of the country there appears to be a lack of substantial geographic differences in hypertension awareness comparing the ‘‘Stroke Belt’’ region (southeastern United States) with the country as a whole in racial assessment. However, there appears to be a trend toward better treatment and control in the Stroke Belt region. The prevalence of hypertension is as high as 65% in persons older than 60 years. Increasing BMI, an epidemic in this country, was independently From the Rush University Medical Center, Chicago, IL Address for correspondence: Philip R. Liebson, MD, Rush University Medical Center, 1653 West Congress Parkway, Chicago, IL 60612 E-mail: pliebson@rush.edu Manuscript received April 24, 2009; revised April 27, 2009; accepted May 1, 2009