Treating Systolic Hypertension

Summarized by Robert W. Griffith, MD
August 16, 2006

Summary

Treatment of systolic hypertension in older persons is of proven benefit if the systolic pressure is above 160 mm Hg. Treating lower systolic levels is desirable in some cases.

Introduction

Systolic hypertension is defined as a systolic blood pressure (the upper number) of at least 140 mm Hg and a diastolic pressure of less than 90 mm Hg¹. It usually affects older people - those over 60 - and it's becoming more common. There's an excellent review of the condition in the Journal of the American Medical Association; we summarize the main points here.

Sources of Evidence

The medical literature from 1966 to 2004 was searched, with the emphasis on randomized controlled clinical trials, and yielded over 1000 articles on systolic hypertension. Thirty-six articles met the criteria of providing data on treatment in the older person.

Evidence in Favor of Treating Systolic Hypertension

Three major trials have examined the treatment of patients with a systolic pressure of 160 mm Hg or above, and diastolic pressure below 90 mm Hg (one trial) or 95 mm Hg (two trials). The subjects' average age varied from 66 to 72 years. The endpoints studied were stroke risk reduction and total cardiovascular risk reduction. In the Systolic Hypertension in the Elderly Program (SHEP) patients were given a diuretic (a water pill, chlorthalidone) or a placebo. If needed, a beta-blocker (atenolol) was added. Average blood pressure reductions were 27 mm Hg (systolic) and 9 mm Hg (diastolic) in the treated patients. The 5-year incidence of stroke was 8.2% in the placebo group and 5.2% in the treated group, i.e. a 36% reduction. There was also a 32% reduction in the risk of cardiovascular disease in the treated group.

The Systolic Hypertension in Europe Study compared placebo with a calcium-channel blocking drug (nitrendipine) with an added ACE-inhibitor (enalapril) and diuretic (hydrochlorothiazide), as required. After 2 years, stroke was reduced by 42% in the treatment group (from 3.35% in placebo vs. 1.96% in treated patients), and cardiovascular disease by 29%. Dementia was also cut by half; this effect persisted during an extended follow-up.

In a Chinese trial, the Systolic Hypertension in China Study, nitrendipine was used, with the possibility of adding an ACE-inhibitor (captopril), hydrochlorothiazide, or both; the comparison group received matching placebos. Stroke reduction by treatment was 31% (5.17% in the placebo vs. 3.59% in the treated patients), and cardiovascular event reduction was 28%.

These three studies provide strong evidence of the value of treating systolic hypertension vigorously. The average overall reduction in stroke ranged from 31% to 42%, and that for cardiovascular disease reduction was between 28% and 32%.

Treating Systolic Blood Pressures of 140 to 160 mm Hg

There have been no large-scale studies reported that address this question. Published accounts of small trials show the benefits of drug treatment on the actual blood pressure, but there are no studies reporting effects on more serious outcomes, such as cardiac events and mortality. On the other hand, there are studies showing the risks of having systolic blood pressure over 140 mm Hg.

Treating the Oldest Old?

The number of people living to beyond 80 is increasing rapidly, and many of them have systolic hypertension. Although the benefits are not quite so great in the over- 80 patients studied, they are still significant, so that treatment should usually be undertaken in this age group, too.

How About "White Coat" Systolic Hypertension?

Treatment of this form is still being debated. Studies will one day be reported to resolve the problem.

One Risk of Treatment

It's known that a high 'pulse pressure' - the difference between systolic and diastolic pressure - carries more cardiovascular risks. If drug treatment lowers diastolic pressure to a greater extent than systolic pressure, pulse pressure will be increased. In the SHEP study, an increase in 10 mm Hg of pulse pressure was independently predictive of an increased risk of stroke and heart failure. Care should be taken during treatment, therefore, to ensure that diastolic pressure is not lowered below 70 mm Hg.

Practical Management Decisions

The extent of treatment of systolic hypertension in the elderly is an issue where individual patient considerations must play a large role. Patient preference and tolerance of therapy are important, as well as coexisting conditions that can affect the results. Further studies will provide more guidance, but they will take some years to produce useful results. In the meantime, shared decision-making between doctor and patient should be the rule.

Source

• Systolic hypertension in older persons. SJ. Chaudhry, HM. Krumholtz, JM. Foody, JAMA, 2004, vol. 292, pp. 1074--1080

Footnotes
1. Blood pressure readings are usually given as 2 numbers: for example, 110 mm Hg over 70 mm Hg (often written as 110/70). The first number is the systolic blood pressure reading, and it represents the maximum pressure exerted in the arteries when the heart contracts. The second number is the diastolic blood pressure reading, and it represents the pressure in the arteries when the heart is at rest, between contractions.

Related Links
Which is More Important - the Upper or Lower BP Number?
The Importance of Pulse Pressure
Folic Acid to Prevent Systolic Hypertension?

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