NEW YORK, NY — Another day, another set of hypertension guidelines—or so it is starting to seem for cardiologists and primary-care physicians who've yearned for years for new guidance, only to see three different pieces of advice released in a single month. The timing and varying recommendations in the different documents hint at the discord among experts that has delayed new recommendations for over a decade.
Tuesday, on the eve of yesterday's long-awaited release of guidelines from the JNC 8 panel in the Journal of the American Medical Association (JAMA), the American Society of Hypertension and the International Society of Hypertension released their own clinical practice guidelines. While the focus of their document is on "managing hypertension in the community," the guidance nonetheless carries some echoes of the JNC 8 document, but several key differences as well. Meanwhile, the ACC/AHA issued their "scientific advisory" on managing high BP last month, and the European Society of Hypertension released their own guidance earlier this year.
To heartwire , Dr Michael Weber (State University of New York, Brooklyn), lead author on the ASH/ISH guidance, pointed out that while many of the many of JAMA paper authors were originally appointed to the JNC committee, it is not actually "an official JNC document." Moreover, there had never been any "certainty" that JNC guidelines would ever come out, which is why the ASH/ISH group proceeded with their own guidelines.
Two physicians appointed to JNC 7 but not JNC 8, Drs George Bakris and Barry Materson, are authors on the ASH/ISH guidelines but are not authors on the JAMA/JNC 8 document; meanwhile, three authors on the JAMA/JNC 8 guidelines (Drs Barry Carter, Sandra Taler, and Raymond Townsend) are also coauthors on the ASH/ISH guidelines.
None of the authors on the ACC/AHA "scientific advisory" were members of JNC 7 or 8, and none are authors on the ASH/ISH guidelines.
Guidance for the Hands-on Practitioner?
The ASH/ISH guidelines outline the epidemiology of hypertension and its causes, evaluation, and diagnosis and offer definitions and classifications with the stated aim of offering "a straightforward approach" for physicians anywhere in the world. They also dedicate part of the guidelines to "special issues with black patients," something that is handled in JNC 8 only via specific recommendations, not in a stand-alone section.
Weber pointed to other differences in the ASH/ISH guidelines: "First, they use different criteria for diagnosing hypertension and setting targets in the critical group of patients aged over 60. Second, they give detailed instruction on testing and evaluation of hypertensive patients, areas that are not included in the JAMA article."
The ASH/ISH document also covers treatment-resistant hypertension, a mushrooming research area dominated by catheter-based approaches and not broached in the JNC 8 guidelines.
"Put another way," Weber continued, "the JAMA guidelines are a limited selection of evidence-based recommendations of interest to experts; the ASH/ISH guidelines now fill the gap of providing a reasonably comprehensive set of practical clinical instructions to the front-line practitioners who actually care for people with hypertension."
Similarities and Differences
Both the JNC-8 (JAMA) guidelines, as well as the ASH/ISH guidelines, provide a treatment algorithm table, but physicians examining these side by side will notice some confusing differences.
Recommendations on thresholds for initiating therapy in both documents advocate a somewhat "looser" approach in certain groups (including the <140/90-mm-Hg target in patients with diabetes or chronic kidney disease), but the guidelines diverge on other issues.
For one, the start-treatment threshold of >150/90 mm Hg applies to patients 80 years or older in the ASH/ISH guidelines, as opposed to 60 years or older in JNC 8. The ASH/ISH document also suggests different drugs from the JNC 8 recommendations for initial therapy, depending on the patients' race, age, and blood-pressure level. While JNC 8 stated that an ACE inhibitor, angiotensin-receptor blocker (ARB), calcium channel blocker (CCB), or thiazide-type diuretic were all reasonable initial choices in nonblack patients, the ASH/ISH guidelines recommend an ACE inhibitor or ARB for nonblack patients under age 60 and a CCB or thiazide in nonblack patients over 60.
For black patients, in keeping with JNC 8, the ASH/ISH guidance recommends a CCB or thiazide. In patients with BPs of at least 160/100, the ISH/ASH guidance recommends starting with two drugs from the get-go and has separate drug recommendations for special populations.
The differences between documents are enough to make anyone's blood pressure climb and may have been what provoked the ASH/ISH authors to observe: "Because of the major differences in resources among points of care it is not possible to create a uniform set of guidelines. For this reason, we have written a broad statement . . . and we expect that experts who are familiar with local circumstances will feel free to use their own judgment."
The Burden of Proof
Asked about some of the differences between the ASH/ISH and JNC 8 documents, ASH president and coauthor Dr William B White (University of Connecticut, Farmington) acknowledged that these may be confusing for practicing physicians.
"The major difference in JNC 8 and JNC 7 is that JNC 8 stuck to very stringent evidence-based criteria—there were only a couple of placebo-controlled studies that evaluated people over the age of 60 with systolic hypertension ( SHEP and Syst-EUR ) and one study in patients over the age of 80 ( HYVET )," White told heartwire in an email. "The JNC 8 panel decided that they could not recommend a lower threshold value for those over 60 since no evidence existed that <140 mm Hg was better than <150 mm Hg for protecting patients from harm. The ASH and ISH [guideline writers] felt, since many patients between 60 and 80 years of age had been studied in ALLHAT , ACCOMPLISH , and VALUE , which used <140/90 mm Hg as a guide for therapy and that the only data for >80 years old was from HYVET (which started with 160 mm Hg or higher to initiate treatment and had achieved SBPs of 146 mm Hg for the treatment group), that the recommendation for <150 [as opposed to <140 mm Hg] should be used only in those over 80 years of age."
The debate really centers on the lack of randomized controlled trial evidence in these older patients, he stressed.
"Definitely [it] is a point of contention, since JNC 8 could be construed as correct based on strict evidence, but no one can really argue that getting 60-plus-year-old patients to 140 is not a bad thing either."
The 13-page ASH/ISH guidelines are published in the Journal of Clinical Hypertension and the Journal of Hypertension in Europe.
Weber discloses research funding from Medtronic, consulting fees from Boehringer-Ingelheim, Novartis, Daiichi Sankyo, Takeda, and Forest, and speaker fees from Daiichi Sankyo, Takeda, and Forest. White discloses research funding from the National Institutes of Health; consulting fees from safety committees (DSMB, CEC, steering committees), Ardea Biosciences, AstraZeneca, Dendreon, Forest Research Institute, Roche, St Jude Medical, Takeda Global Research, and Teva Neuroscience.
Heartwire from Medscape © 2013
Cite this: ASH/ISH Issue Separate Hypertension Guidelines From JNC 8, Hinting at Discord - Medscape - Dec 19, 2013.