Monday, January 5, 2015

JNC 8: Key Features of the New Hypertension Guidelines for Physician Assistants

JNC 8: Key Features of the New Hypertension Guidelines for Physician Assistants
About 31% of american adults have hypertension (65 million). In the US, only 50% of patients with hypertension are being treated to target BP levels. If you look at patients with uncontrolled hypertension, 90% have a usual source of healthcare and have health insurance. This means that the shortfall is action by the clinician! Yes, you, the physician assistant!

If you are completely new to medicine, JNC stands for the Joint National Committee and typically releases guidelines on hypertension management. From the table below, we know that the this is the first release in 11 years. Let’s first begin by talking about a few obvious changes for JNC 8 from previous years.

  1. While the Joint National Committee is typically commissioned by the National Heart, Lung, and Blood Institute (NHLBI), JNC 8 was actually tasked by the American College of Cardiology (ACC) and the American Heart Association (AHA) in June of 2013.
  2. You’ll notice a title change in JNC 8 from previous years - this was no mistake. ACC and AHA decided that since they had recently released guidelines on assessing and managing cardiovascular risk, treating cholesterol and managing obesity, a name change was necessary. This was not the first time the title has changed in the past - see highlights in red.
  3. The JNC panel was made up of more family practitioners since its guidelines were directed toward primary care, a significant change from previous JNC panels, which are made up of primarily cardiology and hypertension experts. This is a good thing! It’s good to see some of “our people” in the news. Primary care FTW (for-the-win)!
Evidence-Based Guidelines for the Management of High Blood Pressure in Adults
The Seventh Report of the JNC on Prevention, Detection, Evaluation and Treatment of High Blood Pressure
The Sixth Report of the JNC on Prevention, Detection, Evaluation and Treatment of High Blood Pressure
The Fifth Report of the JNC on Detection, Evaluation, and Treatment of High Blood Pressure
The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents



Now, enough about the logistics. Let’s talk about the actual content and you need to know.

  1. JNC 8 utilized a more systematic literature review. The panel decided to use a strict criteria, limiting the number of randomized controlled trials used in their study to only those of high quality. If you have not taken an evidence based medicine course, just disregard this and know that JNC took an approach that ensured its data was heavily supported. This amounted to about 1.7-2.4% of the articles initially screened for each of the three questions answered. Of these, only 0.6% were of “good” quality.
  2. JNC 8 content was more focused - limited to answering 3 questions related to hypertension management in adults (18+). Unlike JNC 7, however, this report did not cover prehypertension and hypertension definitions, methods of BP measurement, patient evaluation, secondary hypertension, resistant hypertension, or lifestyle intervention.
  3. The panel generated 9 recommendations from their analysis of the randomized controlled trials. Each was graded according to criteria: A (strong), B (moderate), C (weak), or E (expert opinion). Recommendations 1-5 address the first 2 questions and 6-8 address the third question. Recommendation 9 and a treatment algorithm were produced to allow further guidance “to assist in implementation of recommendations 1 through 8.”

1. Does initiating drug therapy at specific BP thresholds improve health outcomes?
2. Does drug treatment to specified goals improve health outcomes?
3. Do different drugs or drug classes differ in benefits and harms?

While I won’t list out the 9 recommendations, I will list briefly a summary and the differences from JNC 7.

Differences from JNC 7
In patients over 60, start treatment for BP 150 mmHg systolic or 90 mmHg diastolic or greater, and treat to under those thresholds. If a patient tolerates a lower BP, do not adjust treatment to raise BP closer to 150 mmHg.
Previously this threshold was 140 mmHg systolic in JCN 7.
In patients under 60, treatment thresholds and goals should be 140/90 mmHg. Use this same guideline for patients with diabetes or CKD.

In non-black patients with HTN, initial treatment can be a thiazide diuretic, CCB, ACE inhibitor, or ARB. For black patients, initial therapy should be a thiazide diuretic or CCB. If control is not reached on 3 of these medications, the guidelines recommend referral to a specialist.
Beta-blockers no longer listed as a first-line choice, leaving only thiazide diuretics, ACE inhibitors, ARBs and CCBs.
Thiazide diuretics no longer favored as first-line treatment; on equal footing with other 3 classes.
In patients with CKD, initial or add-on therapy should be an ACE inhibitor or ARB, regardless of race or diabetes status.
Warnings about combining ACE inhibitors with ARBs, causing hypotension, acute renal failure, and hyperkalemia.

What Does This Tell Us?
  1. Almost all of the literature accepted was disregarded, which means there is not enough solid evidence available to support the panel’s questions definitively. This implies that the research currently available over the past decade or so is not answering the questions we are asking. We need to shift our research methods to fill this gap in the future - this research will come from students and physician assistants just like you. Consider these questions when your thesis comes around.
  2. Most of their recommendations are classified as grade E (expert opinion) because evidence was insufficient, unclear, or conflicted. Following the release of JNC 8, a panel of JCN 8 members released an article stating that the higher BP target range of 150/90 for adults over 60 could leave them at greater risk for complications.
  3. The JNC 8 panel took an entirely different approach to writing hypertension guidelines, but it was more narrowly focused and had its own limitations because of available research and methodology. It was a much simpler document than previous guidelines and had a single BP recommendation for both the pharmacologic treatment threshold and treatment goal for patients 18-60 and patients with diabetes or CKD. JNC 8 reduced the number of first line drugs from 5 to 4 and recommended specific drugs for 3 subpopulations.
  4. These are but guidelines and should be treated as such in decision making. Patient care requires tailoring to each patient’s needs factoring in their finances, compliance, culture, safety, and efficacy of treatment.

JAAPA - August and November 2014

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