New hypertension guidelines: One size fits most?

The report of the panel appointed to the eighth Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 8),¹ published in December 2013 after considerable delay, contains some important changes from earlier guidelines from this group.² For example:

• The blood pressure goal has been changed to less than 150/90 mm Hg in people age 60 and older. Formerly, the goal was less than 140/90 mm Hg.
• The goal has been changed to less than 140/90 mm Hg in all others, including people with diabetes mellitus and chronic kidney disease. Formerly, those two groups had a goal of less than 130/80 mm Hg.
• The initial choice of therapy can be from any of four classes of drugs: thiazide-type diuretics, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, or angiotensin receptor blockers (ARBs). Formerly, the list also contained beta-blockers. Also, thiazide-type diuretics have lost their “preferred” status.

The new guidelines are evidence-based and are intended to simplify the way that hypertension is managed. Below, we summarize them—how they were developed, their strengths and limitations, and the main changes from earlier JNC reports.

WHOSE GUIDELINES ARE THESE?

The JNC has issued guidelines for managing hypertension since 1976, traditionally sanctioned by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health. The guidelines have generally been updated every 4 to 5 years, with the last update, JNC 7,² published in 2003.

The JNC 8 panel, consisting of 17 members, was commissioned by the NHLBI in 2008. However, in June 2013, the NHLBI announced it was withdrawing from guideline development and was delegating it to selected specialty organizations.^3,4 In the interest of bringing the already delayed guidelines to the public in a timely manner, the JNC 8 panel decided to pursue publication independently and submitted the report to a medical journal. It is therefore not an official NHLBI-sanctioned report.

Here, we will refer to the new guidelines as “JNC 8,” but they are officially from “panel members appointed to the Eighth Joint National Committee (JNC 8).”

THREE QUESTIONS THAT GUIDED THE GUIDELINES

Epidemiologic studies clearly show a close relationship between blood pressure and the risk of heart disease, stroke, and kidney disease, these risks being lowest at a blood pressure of around 115/75 mm Hg.⁵ However, clinical trials have failed to show any evidence to justify treatment with antihypertensive medications to such a low level once hypertension has been diagnosed.

Patients and health care providers thus face questions about when to begin treatment, how low to aim for, and which antihypertensive medications to use. The JNC 8 panel focused on these three questions, believing them to be of greatest relevance to primary care providers.

A RIGOROUS PROCESS OF EVIDENCE REVIEW AND GUIDELINE DEVELOPMENT

The JNC 8 panel followed the guideline-development pathway outlined by the Institute of Medicine report, Clinical Practice Guidelines We Can Trust.⁶

Studies published from January 1966 through December 2009 that met specified criteria were selected for evidence review. Specifically, the studies had to be randomized controlled trials—no observational studies, systematic reviews, or meta-analyses, which were allowed in the JNC 7 report—with sample sizes of more than 100. Follow-up had to be for more than 1 year. Participants had to be age 18 or older and have hypertension—studies with patients with normal blood pressure or prehypertension were excluded. Health outcomes had to be reported, ie, “hard” end points such as rates of death, myocardial infarction, heart failure, hospitalization for heart failure, stroke, revascularization, and end-stage renal disease. Post hoc analyses were not allowed. The studies had to be rated by the NHLBI’s standardized quality rating tool as “good” (which has the least risk of bias, with valid results) or “fair (which is susceptible to some bias, but not enough to invalidate the results).

Subsequently, another search was conducted for relevant studies published from December 2009 through August 2013. In addition to meeting all the other criteria, this bridging search further restricted selection to major multicenter studies with sample sizes of more than 2,000.

An external methodology team performed the initial literature review and summarized the data. The JNC panel then crafted evidence statements and clinical recommendations using the evidence quality rating and grading systems developed by the NHLBI. In January 2013, the NHLBI submitted the guidelines for external review by individual reviewers with expertise in hypertension and to federal agencies, and a revised document was framed based on their comments and suggestions.

The evidence statements are detailed in an online 300-page supplemental review, and the panel members have indicated that reviewer comments and responses from the presubmission review process will be made available on request.

NINE RECOMMENDATIONS AND ONE COROLLARY

The panel made nine recommendations and one corollary recommendation based on a review of the evidence. Of the 10 total recommendations, five are based on expert opinion. Another two were rated as “moderate” in strength, one was “weak,” and only two were rated as “strong” (ie, based on high-quality evidence).