Who Put the Die in Diastolic?
Who Put the Die in Diastolic?
Abstract & Commentary
Synopsis: Systolic blood pressure is a better predictor of cardiovascular and coronary heart disease mortality in men being treated for hypertension than is diastolic blood pressure.
Source: Benetos A, et al. Arch Intern Med. 2002;162:577-581.
Benetos and colleagues recruited 4714 hypertensive men between 1972 and 1988 at the Centre d’Investigations Preventives et Cliniques in Paris. Supine blood pressure was carefully and manually measured, as were standard cardiovascular risk factors including tobacco use, diabetes, and serum cholesterol. Mortality data were collected an average of 14 years (range, 9-25) later for this cohort (through 1997). Control of hypertension was considered to be a systolic blood pressure below 140 mm Hg and a diastolic blood pressure below 90 mm Hg. Subjects were also stratified by levels of systolic and diastolic blood pressure to assess the effect of each. Relative risk (RR) and confidence intervals (CI) were calculated controlling for age, cholesterol, smoking, and diabetes. The RR of systolic blood pressure was calculated controlling for diastolic blood pressure, and vice versa.
The mean age of the group was 52 years. Mean blood pressure was 152/94 mm Hg. Only 14.5% of the patients had controlled values for both systolic and diastolic blood pressure, but systolic blood pressure was more likely (10.8 %) to be uncontrolled than was diastolic pressure (4.2 %). Those with uncontrolled blood pressure had increased RR for cardiovascular mortality (1.66; CI, 1.04-2.64) and coronary heart disease (CHD) mortality (2.35; CI, 1.03-5.35) compared to those with controlled blood pressure.
There was a linear relationship between systolic blood pressure and both cardiovascular and CHD mortality. Those with systolic blood pressure between 140 and 159 mm Hg had an age-adjusted cardiovascular mortality RR of 1.69 (CI, 1.03-2.76) and CHD RR of 2.54 (CI, 1.08-5.96) compared to those with systolic blood pressure below 140 mm Hg. The adjusted RRs for cardiovascular and CHD mortality in those with a systolic blood pressure of 160 mm Hg or more compared with those who had a systolic blood pressure below 140 mm Hg were 2.52 (1.56-4.09) and 3.51 (1.51-8.2), respectively. The increased risk of cardiovascular mortality was significantly higher in those with systolic blood pressure higher than 140 compared with those with systolic blood pressure under 140 after controlling for age, for the other cardiovascular risk factors, and for diastolic blood pressure. With regard to diastolic blood pressure, however, the relationship between diastolic blood pressure and cardiovascular mortality was not significant after adjusting for age, other associated risk factors, and systolic blood pressure.
Pulse pressure had essentially the same cardiovascular and CHD mortality predictive value as did systolic blood pressure.
Comment by Barbara A. Phillips, MD, MSPH
For at least 30 years, evidence has been accumulating that systolic blood pressure is a better indicator of cardiovascular risk than is diastolic blood pressure.1,2 Indeed, the National High Blood Pressure Education Program has recently recommended that systolic blood pressure be the main criterion for the diagnosis, staging, and treatment of older Americans.3 Isolated systolic hypertension is the most prevalent kind of hypertension in the general population,4 and is also the most difficult to control.5 Indeed, a companion article to the one under discussion documented that systolic blood pressure control was much less frequent than diastolic blood pressure control (29.9% vs 41.5%) both in the office and at home.6 Not only does uncontrolled systolic blood pressure predict increased cardiovascular risk (unlike diastolic blood pressure), effective treatment of isolated systolic hypertension has been shown to dramatically reduce the risk of myocardial infarction, heart failure, and stroke.5,7 We simply have got to do a better job of treating systolic hypertension.
References
1. Kannell WB, et al. J Am J Cardiol. 1971;27:335-346.
2. Black HR. Hypertension. 1999;34:386-387.
3. Izzo JL, Levy D, Black HR. Hypertension. 2000;35: 1021-1024.
4. National High Blood Pressure Education Program Working Group. Hypertension. 1993;275-285.
5. Alexander M, et al. Arch Intern Med. 1999;159: 2673-2677.
6. Mancia G, et al. Arch Intern Med. 2002;162:582-586.
7. SHEP Cooperative Research Group. JAMA. 1991;265: 3255-3264.
Phillips, Professor of Medicine, University of Kentucky; Director, Sleep Disorders Center, Samaritan Hospital, Lexington, KY, is Associate Editor of Internal Medicine Alert.
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