European hypertension guidelines sharply at odds with JNC 7

Wed, 11 Jun 2003 20:00:00

Milan, Italy - The European Society of Hypertension (ESH) and the European Society of Cardiology (ESC) have released new joint guidelines on the management of high blood pressure. The new document represents the first European guidelines that have not simply been adapted from World Health Organization/International Society of Hypertension (ISH) recommendations, as they have been previously.

The guidelines are published in the June 2003 issue of the Journal of Hypertension, the joint journal of the ESH and the ISHwhich has also endorsed the new guidelinesand will be formally presented at the ISH/ESH meeting later this week in Milan, Italy.

Chair of the guidelines committee was Prof Giuseppe Mancia (Università degli Studi Milano-Bicocca, Italy), and chair of the writing committee was Prof Alberto Zanchetti (Centro di Fisiologia Clinica e Ipertensione, Milan, Italy).

"The philosophy of these guidelines is to be informative and educational, rather than prescriptive, because our strong opinion on the committee was that one of the major reasons for the past lack of success of guidelines in influencing the practice of medicine is that they try to be too schematic and too prescriptive," Zanchetti told heartwire . "I think their role is to give good information to doctors and then leave doctors free to take decisions in the individual cases they are confronted with. After all, medicine is treating individual persons."

The new document differs sharply in several ways from the American guideline known as the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7), released last month.

No prehypertension here

Among the major differences, Zanchetti says, is that they have retained their previous classification of blood pressures between 120/80 mm Hg and 129/84 mm Hg as "normal" and 130/85 mm Hg and 139/89 mm Hg as "high normal." "We're sticking more or less to the previous specification of WHO/ISH, and we have not adopted the concept of 'prehypertension' that JNC 7 thoughtI think unhappilyto consider," he said.

The JNC 7 document calls 120 to 139 mm Hg systolic or 80 to 89 mm Hg diastolic pressures "prehypertension" and recommends lifestyle modification to lower blood pressure in these people, in an effort to express this range as requiring action.

Instead, Zanchetti said, they feel they have given high-normal pressures their due weight by combining them with calculation of global cardiovascular risk, which their group sees as the best guide as to whether or how intensively to treat and a concept that has "all but disappeared" from the American guidelines. In patients with diabetes or previous cardiovascular disease, for example, these levels of blood pressure are considered a signal to treat. In addition, the goal BP should not be <140/90 mm Hg in these patients but <130/80 mm Hg. The resources available in most countries in Europe also allow use of other diagnostic tools such as echocardiography, carotid ultrasound, and the presence or absence of microalbuminuria to be used to better define an individual's risk, the ESH/ESC document notes.

All drug classes shown to be effective

When it comes to treatment, the European guidelines take the position that all classes of antihypertensive medications can be considered as initial therapy. "Most of the recent trials have shown that the benefits are not so different from one kind of treatment to the other one, so they are really confirming what was written in the previous ISH guidelines that the benefits of antihypertensive treatments are basically due to blood-pressure lowering per se, and in this consideration, all of the major antihypertensive classes have been shown to be effectivediuretics, beta blockers, ACE inhibitors, calcium antagonists, and angiotensin antagonistsso all of them can be used for initiating antihypertensive therapy," Zanchetti said.

Various other factors will be taken into the decision, including the cost of drugs, the cardiovascular risk profile of the patient, the presence or absence of target organ damage, diabetes or other concomitant disease, "and of course also patient preference, which is very important to get compliance with treatment," Zanchetti noted. The debate on which drug to use to initiate treatment "is in our opinion somewhat outdated by the fact that in probably two thirds to three quarters of hypertensive patients we need at least two drugs, if not three, in combination to achieve the goal of <140/90."

These recommendations differ sharply again from JNC 7, where guidelines suggest that in the absence of "compelling" indications in high-risk patients, diuretics either alone or in combination with other agents should be the first line of treatment of uncomplicated hypertension.

The position taken in JNC 7 on diuretics has been perceived as based largely on findings of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), of which many on the writing group were investigators. In the European guidelines document, the authors devote a section to discussion of the limitations of this trial. "Although ALLHAT stands out as the largest double-blind trial undertaken in hypertensive patients, interpretation of its results is difficult for several reasons, which may account for the heterogeneity of ALLHAT results with respect to those of the other trials," they write.

Similar philosophy, different methods of approach

Dr William C Cushman (University of Tennessee Health Science Center, Memphis) was a member of the writing committee for the US guidelines and an ALLHAT investigator. Cushman told heartwire that he feels the philosophy of the two documents is actually very similar. "Obviously, we're all looking at the same data, a lot of the same concerns are there, we're just approaching it a different way," he said.

For example, in terms of the classification, he notes that feedback from physicians on JNC 6the previous US guidelines that also used the "high-normal" designation retained by the Europeans as well as "stage 3" hypertensionhad suggested that the previous classification system was "just too complex for physicians to pay attention to." They were mandated to make it simpler while still being consistent with the evidence.

The main difference, then, is that the European guidelines incorporate the calculation of absolute risk to influence decisions about whom and when to treat. "What we foundand I think this is even true in their guidelinesis that when all is said and done, [absolute risk] doesn't really influence whom we treat as much as we might like to think it should," Cushman said.

For those with blood pressures above 140/90 mm Hg, for example, it might be possible to identify a low-risk group, but in the end, even the European guidelines suggest the low-risk people in this group may actually benefit most from early and long-term treatment. For those who are high normal, or prehypertensive in JNC 7 terms, there may be high-risk people who could benefit from treatment based on their global risk, but, Cushman says, these people are generally at high risk because they have heart failure, are post-MI, or have diabetic nephropathygroups that, even though they are not technically hypertensive, are recommended for treatment in JNC 7 since benefits of treatment in these groups appear to be independent of blood-pressure lowering.

For those who are in this blood-pressure range and who do not have compelling indications for treatment, although they have apparent increased global risk based on risk-factor calculations, "we just don't have the clinical trial evidence to prove that if you treat based on the blood-pressure level and risk classification that you're benefiting those people," Cushman said.

Continental divide

Perhaps more real is the division between the documents on how to begin treatment, but even here, Cushman says, there is a great deal of overlap in the end. "That's one of the few areas where there are important, I guess, conceptual differences between the guidelines," he said. Basically, both documents recognize the value of several classes of drugs, including diuretics, beta blockers, calcium antagonists, ACE inhibitors, and angiotensin receptor antagonists, in treating hypertension. "What we've done is go the extra step and say we believe the clinical trial evidence is strong enough to say that diuretics should be used first in most patients, and certainly if you start someone on two drugs, then a diuretic should almost always be included. They actually summarize much of the same data but then give reasons that they don't want necessarily to go along with the better outcomes with diuretics."

Regardless of which drug is used first, though, both documents "agree completely" that most patients will end up on multidrug regimens to control BP, Cushman said. The difference lies in how these regimens would be approached. The ESH/ESC guidelines recommend slow titration of drugs and substitution of one drug for another when blood-pressure control is not achieved. In contrast, JNC 7 recommends drugs be added rather than substituted, unless the patient cannot tolerate a given drug.

At the end of the day, he said, "JNC 7 is a US guideline, meant to apply to the care of Americans. What we're looking at is the way American physicians practice, at what our population looks like," he said. "Admittedly, if you're not treating African Americans or the elderly nearly as much, but a younger white population, and you don't care about cost, then it may not be as big a difference."

"In the US, however, where health coverage is not universal, cost is a real consideration to the public health management of American hypertensive patients. I'm very concerned that we have a large population who can't afford their medications. If they don't fill the prescription, they're not going to take the drug, and that's been well documented."

An upcoming HeartBeat audio program on theheart.org will feature a panel debate on both sets of new guidelines, moderated by a hypertension expert from a different continent altogether, Dr Lionel Opie (University of Cape Town Medical School, South Africa), and featuring Dr Franz H Messerli (Ochsner Clinic Foundation, New Orleans, LA) and Dr Joseph L Izzo Jr (State University of New York, Buffalo).

Heartwire from Medscape © 2003 

Cite this: European hypertension guidelines sharply at odds with JNC 7 - Medscape - Jun 11, 2003.