ATHENS, GREECE — Should guidelines educate or merely inform? Should they rely on the most rigorous randomized-clinical-trial (RCT) evidence or leave ample room for expert opinion? Whose guidelines, among the three separate sets of recommendations released in the past year, are the best?
Those were the key questions to emerge during a special session here at HYPERTENSION 2014 , the joint conference of the European Society of Hypertension (ESH) and the International Society of Hypertension (ISH), dedicated to the 2013 ESH/European Society of Cardiology (ESC) guidelines, the JNC 8/JAMA guidelines, and the American Society of Hypertension (ASH)/ISH guidelines.
No clear winner emerged. Although debate was billed, all three presenters representing the different documents admitted they were mostly in accord on the major points.
All three, for example—Dr Giuseppe Mancia (University of Milano-Bicocca, Milan, Italy), Dr John B Kostis (Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ), and Dr Ernesto Schiffrin (Jewish General Hospital, Montreal, QC)—made the point that a minority of the recommendations in the documents are actually based on the highest level of evidence.
Mancia, tasked with presenting and defending the ESH/ESC guidelines, noted that, in JNC 8, a full 60% of recommendations were based on expert opinion, while just 10% were based on "strong" clinical-trial evidence. But by the same token, he continued, in the ESH/ESC guidelines, only one-fourth of the recommendations were given a classification of 1A—the highest level of evidence.
"Maybe we should call them not evidence-based guidelines, but eminence-based guidelines," he quipped.
Level of Evidence
Mancia also took a dim view of JNC 8's dependence on RCT evidence (to the exclusion of other research), as well as its omission of high-quality RCTs in which blood pressure was not a specific study end point.
"Evidence on some important treatment recommendations cannot be collected via RCTs, but only via observational studies," he argued. An extreme example of this is the fact that all guidelines recommend lifetime treatment with antihypertensive drugs, but all RCTs typically run just three to five years. "To be consistent with its decision to use only RCTs as evidence, JNC 8 should recommend that antihypertensive medicines be stopped after five years," Mancia suggested, tongue in cheek.
Kostis, speaking on behalf of JNC 8 (although he himself was not on the committee), took this point even further, joking that nowhere in the definition of "evidence" is the word "randomized" used.
In fact, basing guidelines on a small number of RCTs alone introduces errors of omission, he argued, along with a number of other problems. Not treating because there is no evidence is simply unethical, he concluded.
Besides, he noted, any squabbling over specific recommendations will just distract from the task of working together to get soaring blood pressures under control.
Points of Difference
Schiffrin, focusing on the ASH/ISH guidelines, summarized some of the key ways in which the guidelines differ, noting that the most controversial difference was the cutoff of age 60, rather than 80, in the JNC 8 guidelines, as the age at which a higher systolic-blood-pressure target (150 mm Hg) could be used. Recommendations for when to use or start different classes of drugs and whether this should be tailored to special groups also differed between guidelines, he noted.
But for the most part, he said, "there are not such big differences" between the guidelines. And that may not be such a bad thing, he argued. "I think [the different advice] is good because it has generated controversy, and that has made people more aware of the need to control BP and more aware of the evidence and lack of evidence."
A Call for Simplicity
That larger aim is the reason the ASH/ISH guidelines have stressed simplicity and readability, Schiffrin continued. This point, rather than the disputed evidence base, proved to be the most contentious point of Monday's session.
The ESH guidelines run 74 pages and make a number of recommendations that are not available to health professionals in low- and middle-income countries, Schiffrin observed.
"We [the ASH/ISH guideline committee] think that standardized global guidelines may save many lives and prevent devastating strokes and heart attacks. . . . Therefore, what we need to concentrate on are not the minor differences between different guidelines and whether there is perfect evidence—which we have seen is often not there—but rather how to implement recommendations in an easy-to-follow way that will allow us to improve BP around the world."
Mancia, however, took umbrage at the suggestion that the ESH/ESC guidelines were too lengthy and complex, with recommendations on diagnostic tools not universally available.
"I think guidelines must have an educational value; otherwise, if we only provide simple statements without explaining why, this inevitably means creating prescriptive and coercive guidelines, rather than recommendations," he argued. "Educational value, which means trying to explain the reason for any recommendations, is necessary, and that means finding a compromise between education and simplicity."
Schiffrin, however, held his ground, bidding his protagonist take the time to read the ASH/ISH document and to consider the short attention spans of doctors. "It's readable, educational, and well referenced—I think it has a greater chance of being followed."
For and Against RCTs
Following the presentations and debate, Dr Alberto Zanchetti (University of Milan, Italy), a coauthor on the ESH/ESC guidelines, headed to the microphone saying he felt someone should say something in support of the need for randomized controlled-trial evidence.
"I certainly share the [concerns over] limitations of RCTs, but at least when it comes to interventions, I think RCTs are a bit like democracy to Winston Churchill." Churchill famously called democracy the worst form of government, except for all the other forms. "I think we need to keep in mind that when you want to evaluate interventions, RCTs are not perfect, but they are still the best way," Zanchetti said.
Kostis, who managed to inject the most humor into his JNC-8 defense, scored the highest points with the audience when he headed back to the microphone to defend observational research and common sense. Citing a 2003 paper from BMJ, Kostis observed that parachutes reduce the risk of injury after gravitational challenge, but their effectiveness has not been proven with randomized clinical trials. The only way to settle this question once and for all would be via a randomized, controlled, crossover trial, he suggested, drawing hoots of laughter from the audience.
Kostis disclosed grants from Novartis and serving on advisory boards for Amgen, St Jude, and speakers bureaus for Bristol-Myers Squibb/Pfizer and Sanofi. Other speakers provided no disclosures.
Heartwire from Medscape © 2014 Medscape, LLC
Cite this: Which New Hypertension Guidelines Are the Best? - Medscape - Jun 16, 2014.