Hypertension in America: A National Reading

November 1, 2005
Supplements and Featured Publications, Hypertension in America: Overcoming Barriers to Blood Pressure Control, Volume 11, Issue 13 Suppl

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.

1. Himmelmann A, Hedner T, Hansson L, O’Donnell CJ, Levy D. Isolated systolic hypertension: an important cardiovascular risk factor. Blood Press. 1998;7:197-207.

2. Kannel WB. Hypertension as a risk factor for cardiac events—epidemiologic results of long-term studies. J Cardiovasc Pharmacol. 1993;21(suppl 2):S27-S37.

3. Kannel WB. Framingham study insights into hypertensive risk of cardiovascular disease. Hypertens Res. 1995;18:181-196.

4. Hajjar I, Kotchen TA. Trends in prevalence, awareness, treatment, and control of hypertension in the United States, 1988-2000. JAMA. 2003;290:199-206.

5. Lewington S, Clarke R, Qizilbash N, Peto R, Collins R. Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies. Lancet. 2002;360:1903-1913.

6. Wang Y, Wang QJ. The prevalence of prehypertension and hypertension among US adults according to the new joint national committee guidelines: new challenges of the old problem. Arch Intern Med. 2004;164:2126-2134.

7. Chobanian A, Bakris G, Black H, et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA. 2003;289:2560-2571.

8. US Department of Health and Human Services. Healthy People 2010: Understanding and Improving Health. 2nd ed. Washington, DC: US Government Printing Office; 2000.

9. Burt VL, Cutler JA, Higgins M, et al. Trends in the prevalence, awareness, treatment, and control of hypertension in the adult US population. Data from the health examination surveys, 1960 to 1991. Hypertension. 1995;26:60-69.

10. Fields LE, Burt VL, Cutler JA, Hughes J, Roccella EJ, Sorlie P. The burden of adult hypertension in the United States 1999 to 2000: a rising tide. Hypertension. 2004;44:398-404.

11. Thaker D, Frech F, Suh D, et al. Prevalence of hypertension and ethnic differences in sociodemographic and cardiovascular health characteristics of US hypertensives. Am J Hypertens. 2005;18(suppl 1):A117.

12. Oliveria SA, Lapuerta P, McCarthy BD, L’Italien GJ, Berlowitz DR, Asch SM. Physician-related barriers to the effective management of uncontrolled hypertension. Arch Intern Med. 2002;162:413-420.

13. Borzecki AM, Oliveria SA, Berlowitz DR. Barriers to hypertension control. Am Heart J. 2005;149:785-794.

14. Hajjar I, Miller K, Hirth V. Age-related bias in the management of hypertension: a national survey of physicians’ opinions on hypertension in elderly adults. J Gerontol A Biol Sci Med Sci. 2002;57:M487-M491.

15. Hyman DJ, Pavlik VN. Self-reported hypertension treatment practices among primary care physicians: blood pressure thresholds, drug choices, and the role of guidelines and evidence-based medicine. Arch Intern Med. 2000;160:2281-2286.

16. Shih SC, Bost JE, Pawlson G. Standardized health plan reporting in four areas of preventive health care. Am J Prev Med. 2003;24:293-300.