Prehypertension and Cardiovascular Risk
Abstract & Commentary
By Harold L. Karpman, MD, Clinical Professor of Medicine, UCLA School of Medicine. Dr. Karpman reports no financial relationship to this field of study.
Synopsis: Because of the high cardiovascular risk associated with prehypertension, both lifestyle and pharmacological interventions should be vigorously utilized to prevent its progression to full-blown hypertension with its associated higher rates of both morbidity and mortality.
Source: Hsia J, et al. Circulation. 2007;115:855-860.
Blood pressure elevations above 115/75 mm Hg in observational studies in over one million middle-aged and elderly persons have been found to be strongly related to heart disease and stroke mortality.1 The last publication of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure in 2003 (JNC7) sought to simplify blood pressure classification by identifying individuals with systolic blood pressure between 120 and 139 mm Hg and a diastolic blood pressure between 80 and 89 mmHg as having prehypertension.2 Prevalence of prehypertension by this definition has been found to be present in 40% of men and 23% of women.3 Estimates of cardiovascular risk for those individuals with prehypertension have ranged from no increase in cardiovascular mortality4 to an 80% increase for overall cardiovascular disease risk in subgroups such as in American Indians.5
The Women's Health Initiative (WHI) carefully studied 161,808 postmenopausal women enrolled at 40 clinical sites. Excluding individuals with prevalent myocardial infarction, stroke, or heart failure at baseline,6-10 Hsia and his colleagues assessed the risk of myocardial infarction, stroke, hospitalized heart failure and cardiovascular death associated with prehypertension in the remaining 60,785 women.11 Prehypertension was present at baseline in 39.5%, 32.1%, 42.6%, 38.7%, and 40.3% of Caucasian, Black, Hispanic, American Indian and Asian women respectively among these postmenopausal women whose average age was 62.8 years. Age, body mass index, and prevalence of diabetes mellitus and hypercholesterolemia increased across the blood pressure categories whereas current cigarette smoking was more prevalent among normotensive women compared to those with prehypertension or hypertension. The results revealed a 36% increase in hospitalized heart failure risk, a 66% increase for any cardiovascular event, a 93% increase risk of stroke, a 58% increase for cardiovascular death and a 76% increase risk for myocardial infarction.
Commentary
After adjusting for multiple covariates, the risks of myocardial infarction, stroke, heart failure and cardiovascular death were higher among women with prehypertension compared with normotensive women and even higher among those with frank hypertension. Compared with other studies, the strength of the WHI analysis lies in its cohort size and diversity. The geographic, socioeconomic and ethnic diversity of the study group also provided a broadly applicable estimate of the risk associated with prehypertension. However, it must be recognized that the analysis is limited because of the absence of men and younger adults. Also, it is important to recognize that this analysis demonstrated increasing age, body mass index, and prevalence of diabetes mellitus and hypercholesterolemia present across the various blood pressure categories raising the possibility that these conventional risk factors which were not measured may have contributed to, or conceivably may have been solely responsible for, the increased cardiovascular risk which was observed to be present in those individuals in the prehypertension category.
Prehypertension is common and tends to be relatively silent since 15% of the women with prehypertension in the WHI analysis were unaware of this condition and another 5.5% were aware but untreated. Because of the high cardiovascular risk associated with prehypertension, both lifestyle12-15 and pharmacological interventions16 should be vigorously utilized to prevent its progression to full-blown hypertension with its associated higher rates of both morbidity and mortality.
References
1. Lewiston S, et al. Prospective studies collaboration. 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.
2. Chobanian AV et al, for the National High Blood Pressure Education Program Coordinating Committee. Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood and Pressure: the JNC 7 report. JAMA. 2003;289:2560-2572.
3. Wang Y, et al. Arch Inter Med. 2004;164:2126-2134.
4. Mainous AG III, et al. Am J Cardiol. 2004;94:1496-1500.
5. Zhang Y et al. Hypertension. 2006;47:410-414.
6. Women's Health Initiative Study Group. Design of the Women's Health Initiative clinical trial and observational study. Control Clin Trials. 1998;19:61-109.
7. Hays J, et al. Ann Epidemiol. 2003;13:S18-S77.
8. Stefanick ML, et al. Ann Epidemiol. 2003; 13:S87-S97.
9. Ritenbough C, et al. Ann Epidemiol. 2003;13:S87-S97.
10. Curb JD, et al. Ann Epidemiol. 2003;13:S122-S128.
11. Hsia J, et al. Circulation. 2007;115:855-860.
12. Elmer PJ, et al. Ann Inter Med. 2006;144:45-495.
13. Appel LJ, et al. N Engl J Med. 1997;336:1117-1124.
14. Sacks FM et al. N Engl J Med. 2001;344:3-10.
15. Effects of weight loss and sodium reduction intervention on blood pressure and hypertension incidence in overweight people with high-normal blood pressure: the Trials of Hypertension Prevention, phase II; the Trials of Hypertension Prevention Collaborative Research Group. Arch Inter Med. 1997;157:657-667.
16. Julius S, et al. N Engl J Med. 1998;339:12-20.
Because of the high cardiovascular risk associated with prehypertension, both lifestyle and pharmacological interventions should be vigorously utilized to prevent its progression to full-blown hypertension with its associated higher rates of both morbidity and mortality.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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