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Hypertension in America: A National Reading
The prevalence of hypertension in the United States is increasing despite increased awareness of the importance of controlling blood pressure (BP). The growing prevalence of obesity is a major factor in the increased prevalence of hypertension; the aging of the population is another factor. Age, weight, and ethnicity are strong predictors of hypertension. Blacks, older individuals, and people with diabetes have the highest rates. Although Healthy People 2010 has established a target of 50% for hypertension control, the most recent National Health and Nutrition Examination Survey indicates that only about 30% of individuals with hypertension have their BP controlled. Several barriers to effective BP control have been identified, including patient access and adherence to therapy and provider failure to initiate or intensify therapy.
(Am J Manag Care. 2005;11:S383-S385)
The relationship between hypertension and cardiovascular disease is well established.1-4 For 40- to 70-year-olds, mortality from a myocardial infarction (MI) or cerebrovascular accidents doubles for each 20-mm Hg increase in systolic blood pressure (BP) above 115 mm Hg.5-7 These significant risks have targeted hypertension, and more recently, prehypertension as important public health goals. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) guidelines recommend early intervention for prehypertension,7 and Healthy People 2010 has established a 50% target for hypertension control in the very near future.8
Given these priorities, the National Health and Nutrition Examination Survey (NHANES) includes questions about detection, management, and treatment of hypertension. Ongoing analysis of NHANES data not only provides continuing insight and perspective about our successes --and failures--in achieving public health goals, but also serves as a guidepost for new opportunities for prevention, management, and treatment.
Early reports of NHANES data showed positive outcomes for increasing public and provider awareness of the importance of controlling high BP. Between 1960 and 1991, hypertension prevalence (defined as =140/90 mm Hg) declined from 36.3% to 20.4% according to NHANES data.9 More recent data, however, indicate that contrary to earlier reports, hypertension prevalence is increasing in the United States.
In 1999-2000, 31.3% of the US population–approximately 65 million individuals–had hypertension,10 a substantial increase from the 20.4% reported just 8 years earlier.4 Hypertension prevalence was highest in non-Hispanic blacks (33.5%), increased with age (65.4% among those aged =60 years), and was higher in women (30.1%).4 Apparently, early successes in the prevention of hypertension have been thwarted to a large extent by the growing prevalence of excess weight and obesity.4,10 When data were adjusted for age, sex, and race/ethnicity, body mass index (BMI) accounted for >30% of hypertension prevalence. The aging of the American population is another factor contributing to growing hypertension prevalence.4,10
The Latest NHANES Data
The most recent NHANES data (2001-2002) presented at the 2005 American Society of Hypertension scientific meeting indicate that hypertension is a worsening public health problem.11 One of every 3 Americans has hypertension,11 a 4.7% increase from previously reported data.4
As with earlier reports, these data continue to indicate that age, weight, and ethnicity are strong predictors of hypertension. Almost 50% of people with hypertension in the United States are =65 years of age, and 7 of 10 elderly Americans have hypertension. Approximately 80% of people with hypertension in the United States are overweight or obese (BMI =25 kg/m2). The highest prevalence occurs among blacks: a 46% prevalence rate compared with 29% among Hispanics, 32% in whites, and 33% in other ethnic groups.11 The impact of the higher rate of hypertension in these ethnic groups is complicated by the finding that Hispanics and blacks had lower levels of education and annual income and greater difficulty accessing healthcare compared with whites and other ethnic groups.
The comorbidity of diabetes among people with hypertension is most likely to occur in Hispanics, followed by blacks, other minorities, and whites (27%, 23%, 20%, and 17%, respectively). Cardiac disease (congestive heart failure, coronary heart disease, angina, or prior MI) was prevalent in 12%, 16%, 20%, and 11% of Hispanics, blacks, whites, or others, respectively. Collectively, these findings show that blacks, older people, overweight individuals, and people with diabetes are disproportionately affected.
Even though 70% of individuals with hypertension are aware of hypertension, this knowledge has not translated into better BP control rates (Figure).11 Despite gains in the number of patients treated for hypertension--50% compared with 42% reported in 2004–only 30% have their BP controlled. These findings clearly suggest an opportunity for improved medication management.
Barriers to Control
Although patient access and adherence to medication is a significant barrier to hypertension control (see article on page S395), providers also contribute to the problem. Accumulating evidence indicates that clinicians often do not agree with hypertension guidelines, and even those who do agree frequently do not adhere to the recommendations.12,13 Failure to initiate or intensify therapy when appropriate is commonplace. In a study of patient visits in a large Midwestern health system, primary care physicians indicated that, on average, 150 mm Hg was the lowest systolic BP at which they would recommend pharmacologic treatment to patients, despite the fact that JNC VI guidelines at the time recommended treatment at 140 mm Hg or higher.12 Pharmacologic therapy was initiated or changed at only 38% of visits, despite documented hypertension for at least 6 months before patient visits.12 Other physician surveys consistently report that many physicians refrain from initiating or intensifying therapy for hypertension even when BP levels exceed treatment targets set by medical guidelines.12-15
Despite the established association between hypertension, advanced age, and cardiac events, surveys have found that 25% of physicians who care for the elderly believe that treating an 85-year-old patient with mild-to-moderate hypertension had more risks than benefits.13,14 A meta-analysis by Lewington and associates, however, showed a strong and direct relationship between usual BP and vascular and overall mortality throughout middle and old age.5 According to the JNC 7 guidelines, hypertension treatment for older individuals should follow the same principles for the general population.7 Although lower initial doses may be indicated to avoid symptoms, the guidelines state that most older patients will need standard doses and multiple drugs to reach BP goals. Thus an appropriate strategy would be to tailor medications to individual patients to minimize risks and maximize benefits.
Conclusion
Although media reports and educational campaigns have raised awareness of hypertension, it nonetheless remains an important and growing public health problem. Analyses of the NHANES data have significant clinical implications, calling for targeted interventions for the elderly and for blacks in particular. In addition, improving hypertension treatment and control in women, Mexican Americans, people with diabetes, or cardiovascular (CV) problems is likely to reduce the risk of CV events in these at-risk populations. However, as in previous years, the most recent NHANES data confirm the disturbing results of earlier reports: treatment of hypertension is not equivalent to control of hypertension. Consistent with the NHANES findings, a study of performance by commercial managed care plans on 4 new Health Plan Employer Data and Information Set measures showed that the mean average of controlling BP was 39%.16
Bridging the gap between treatment and therapeutic goals remains a challenge for the medical community, one best met by continued education about the benefits and safety of different classes of hypertension medications that can be used alone or in combination to achieve appropriate BP control.
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