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5/14/2003

'Joint National Committee' Releases 7th Report on Blood Pressure Control

Cheryl A. Thompson

High blood pressure must be treated with medication, a national group of hypertension experts announced today, and most patients with the disease will require at least two drugs to bring their systolic and diastolic values under control.

The seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) eliminates the risk-stratification system introduced by the sixth report in 1997, urges efficient adjustment of the medication regimen, and replaces the term "high-normal hypertension" with "prehypertension." Released today on the Web site for the Journal of the American Medical Association, the 13-page "practical guide" (PDF) will appear in the May 21 issue.

"Since 1997, much more has been learned about the risk of high blood pressure and the course of the disease," said Claude Lenfant, chair of the National High Blood Pressure Education Program (NHBPEP) coordinating committee, in a prepared statement today. Lenfant is also director of the National Heart, Lung, and Blood Institute. JNC 7 was written by an NHBPEP committee.

Barry L. Carter, a professor at the University of Iowa College of Pharmacy in Iowa City and ASHP's representative to NHBPEP, said he had initially welcomed the risk-stratification system in 1997 because it helped "guide how aggressive therapy should be, but it was very confusing to [health care] providers."

To use the risk-stratification system, providers had to know, in addition to the patient's systolic and diastolic blood pressures, the number of risk factors that person had for the development of cardiovascular disease and whether the person had heart disease, nephropathy, peripheral arterial disease, or retinopathy or had had a stroke or transient ischemic attack.

As for how clinicians should now select a therapeutic regimen, Carter said he believes that JNC 7, which is based on the results of clinical studies, recognizes that the vast majority of patients, especially those with diabetes mellitus or renal insufficiency, will require treatment with two drugs.

"Many patients are going to require three or more [drugs]," he said, adding that the order in which the medications are introduced is not as critical as stated in the 1997 report, but the first or second drug should be a thiazide diuretic.

He said the other key principle in optimizing treatment is to efficiently adjust the regimen "over a reasonably short period of time," using multiple drugs, if necessary, to control blood pressure.

Carter said some people might have expected JNC 7 to appear overwhelmingly in favor of using a diuretic as the initial medication because of the results of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), released in December 2002.

Those results indicated that, among patients with hypertension and a high risk for cardiovascular events, a diuretic be used before an angiotensin-converting-enzyme (ACE) inhibitor or a calcium-channel blocker. The investigation was sponsored by the federal government and involved more than 33,000 patients—over 42,000 patients if one considers those assigned to doxazosin treatment, which was eliminated from the study because of the notably higher frequency of cardiovascular events and likelihood of hospitalization due to congestive heart failure, compared with the other antihypertensive medications.

JNC 7 "pretty much acknowledges that diuretics are generally the preferred therapy and ... that, depending on the population, an ACE inhibitor might be an appropriate thing to start with," Carter said, noting that this type of agent would be particularly well-suited for patients with diabetes mellitus or renal insufficiency. "But then eventually, the vast majority of patients will probably end up on two drugs anyway." In the case of patients with diabetes mellitus or renal insufficiency, he said, the two drugs would be a diuretic and an ACE inhibitor.

The February 2003 release of the results from an Australian study, in which treatment with an ACE inhibitor produced better overall effects than therapy with a diuretic in a total group of about 6,000 patients, might have caused some people to question the ALLHAT findings.

"In reality, if you look at subpopulations in ALLHAT that were analogous to the populations in the Australian trial, the results are pretty similar," Carter said. "The most significant benefit in [ALLHAT's] ACE-inhibitor group occurred in whites, with lesser effects in African Americans." When he compared the results from white patients in ALLHAT with the results from the Australian study, which lacked black patients, he found that the two groups had fared similarly.

In the United States, hypertension is most prevalent in the black population, according to the National Center for Health Statistics, part of the Centers of Disease Control and Prevention.

The decision to use prehypertension, not high-normal blood pressure, to describe a systolic blood pressure of 120–139 mm Hg or a diastolic blood pressure of 80–89 mm Hg reflected popular opinion. Focus groups with a large number of health care providers revealed they "unanimously hated the term high-normal," Carter said. "It implies that there's not a problem."

Coincident with the change in name was a lowering of the minimum value for the category: 10 mm Hg for the systolic blood pressure, and 5 mm Hg for the diastolic blood pressure.

JNC 7's algorithm for the treatment of hypertension is "much more user-friendly" than its predecessor and "easier to visualize and use," Carter said. "The general thrust of the drug therapy algorithm, as well as the text, is for the use of diuretics ... as the initial drug therapy for most patients." He added that the new algorithm includes the table of "compelling indications" warranting initial therapy with a drug other than a diuretic.

The Joint National Committee customarily produces a report, viewed as national guidelines on the treatment of hypertension, every four years or so, which would have placed JNC 7 in 2001. Work on the report was purposely delayed at the behest of Lenfant, Carter said, because of the NHBPEP chair's concern about clinicians' low awareness of and adherence to the previous reports and because "everyone, of course, was awaiting the results of the ALLHAT trial, the largest hypertension study ever conducted."

JNC 7's long version, which Carter said could total a couple hundred pages, is still being written and will likely be on the Internet this summer and available for download to personal digital assistants. A one-page version, intended for display in examination rooms and similar sites, is also forthcoming, he said.

Carter said he and Mark J. Cziraky, representing the American Pharmacists Association, developed JNC 7's tables of antihypertensive drug therapies and both served on various writing panels for the report.

Cziraky is the executive vice president of HealthCore Inc., in Newark, Delaware.