The 2017 ACC/AHA Clinical Practice Guideline for High Blood Pressure

- Jennifer Middleton, MD, MPH

The 2017 Clinical Practice Guideline for High Blood Pressure was released 2 weeks ago by the American College of Cardiology (ACC), the American Heart Association (AHA), and 9 other professional societies. The AAFP was not one of these societies and has not yet endorsed the guideline. The nearly 200 page document is quite comprehensive, including a new classification scheme and updated treatment recommendations for patients with a range of co-morbidities. Given the size and scope of this Clinical Practice Guideline (CPG), it's unsurprising that some of its recommendations are being met with enthusiasm and others, perhaps, less so.

The 2017 CPG redefines normal versus abnormal blood pressure using both systolic and diastolic measurements. They define normal BP as a systolic of <120 mmHg and a diastolic of <80 mmHg, elevated BP as a systolic of 120-129 mmHg and a diastolic of <80 mmHg, stage 1 hypertension as a systolic of 130-139 mmHg or a diastolic of 80-89 mmHg, and stage 2 hypertension as a systolic of > 139 mmHg or a diastolic of > 89 mmHg. To make these diagnoses, the authors stress the importance of both accurate in-office BP measurements and ambulatory BP monitoring.

These definitions will significantly increase the number of persons in the United States with a diagnosis of elevated BP and hypertension. The authors justify this increase by citing meta-analyses showing progressively increasing hazard ratios for cardiovascular disease (CVD) risk beginning at a systolic of 120 mmHg or greater and/or a diastolic of 80 mmHg or greater; given the relatively small numbers of individuals who experience CVD complications at lower BPs, however, the absolute CVD risk increase in this population is modest.

The authors appropriately stress the use of nonpharmacological interventions including weight loss, increased physical activity, a healthy diet, and limited alcohol use, and they cite literature showing the efficacy of each of these interventions. These nonpharmacological interventions are the mainstay of treatment for elevated BP as well as stage 1 hypertension in individuals not at increased risk of CVD. They advise initiating pharmacologic treatment for stage 1 hypertension for individuals with diabetes, chronic kidney disease, established CVD, and/or whose 10-year ASCVD risk is calculated to be equal or greater to 10%; this group also includes persons over the age of 65. All individuals with stage 2 hypertension (>140/90 mmHg) should employ nonpharmacological and pharmacologic interventions, which is unchanged from previous guidelines.

The choice of a systolic of 130 mmHg to define hypertension is not without controversy. A commentary on the new guidelines points out that:

The use of a risk-based approach as well as more aggressive BP targets reflect a strong influence in these guidelines from the SPRINT trial....while SPRINT treated patients to an SBP goal of less than 120 mmHg, because repeated BP measurements in SPRINT are likely lower than what is seen in clinical practice, the guideline recommends a target of less than 130 mmHg, not 120 mmHg.

Similarly, "[t]he selection of a 10% ASCVD risk threshold appears also to have been a compromise, being higher than the threshold used to classify high risk in the lipid guidelines (7.5%) and different from that used in SPRINT (15% Framingham risk)." SPRINT's influence is significant, given its shortcomings, and these compromises feel more expert opinion-based than evidence-based. It should be noted that SPRINT's principal investigator is also one of the co-chairs of this CPG, though, according to the manuscript, he excused himself from acting as chair during the group's discussions about SPRINT. Another commentary notes the lack of data "regarding the balance of harms and benefits of treatment" in patients with this new definition of stage 1 hypertension. Several meta-analyses, including one developed for this guideline, have shown reduced CVD events in patients treated to a systolic BP target of 130 but not reduced mortality.

It's difficult to argue with this CPG's emphasis on nonpharmacologic treatment, ambulatory BP monitoring, team-based care, integration of QI efforts, and population health advocacy. Its new BP diagnosis definitions and treatment goals, however, may be more open to discussion, especially as no primary care societies were involved in their development. As Dr. Lin discussed last week on the blog, you can count on AFP to provide ongoing commentary on this and other new guidelines as they emerge.

Medicine moves fast. AFP is keeping up.

- Kenny Lin, MD, MPH

Two decades ago, an article in American Family Physician would appear once in print and thereafter only be accessible in the stacks of medical libraries (or family physicians' homes). Content represented the best science available at the time of publication, but there was no way to incorporate subsequent medical developments or new information, no matter how critical. Then, after archived issues of AFP went online in 1998, we began taking a series of small steps aimed at directing readers to the most current and relevant information on the website, including the AFP By Topic collections, adding links from older review articles to updated reviews on the same topic, and creating search tools for patient handouts and algorithms.

To keep up with the pace of medicine, we have begun selectively updating articles online with information of high public health importance. For example, during its October 25-26 meeting, the Advisory Committee on Immunization Practices (ACIP) voted to recommend preferential use of the recombinant subunit herpes zoster vaccine (Shingrix) over the herpes zoster live (Zostavax) vaccine for adults age 50 and older. The U.S. Food and Drug Administration had approved the Shingrix vaccine on October 23. Coincidentally, the November 15 issue that had just gone to press contained an article on prevention and management of herpes zoster and postherpetic neuralgia. It was too late to stop the presses, but not too late to incorporate the new ACIP recommendation into the online version of the article, along with an editor's note alerting readers about the new information.

In a different situation, after the Centers for Disease Control and Prevention (CDC) published updated guidance about caring for pregnant women with possible Zika virus exposure and diagnosis, evaluation, and management of infants with possible congential Zika virus infection, we decided to add an editor's note to our April 15 article on common questions and answers about Zika virus to direct readers to the most current CDC guidance. In this case, anticipating that public health recommendations will continue to evolve rapidly, we did not revise the online text of the article but instead pointed readers to the CDC website for future updates.

Finally, we will continue to create new collections of articles on related topics. The most recent AFP By Topic collection on Oral and Dental Conditions includes special bonus content on medical aspects of oral health that was produced in a collaboration between American Family Physician and the Academy of General Dentistry. Are there any topic collections that we don't have yet that you would find useful for your practice?

Caring for patients with asthma: tools & apps

- Jennifer Middleton, MD, MPH

A recent AFP article on "Chronic Cough: Evaluation and Management" states that the prevalence of asthma in patients with chronic cough is between 24-29%. Asthma in adults can be a tricky diagnosis to make and manage, but several tools and apps can help family physicians provide excellent care to these patients.

In-office spirometry can help make the diagnosis of asthma in an adult patient with chronic cough; an obstructive pattern with an FEV1 or FVC that improves with bronchodilator challenge is highly suggestive of asthma and should then prompt an assessment of asthma severity to guide treatment. The Choosing Wisely campaign encourages physicians to "not diagnose or manage asthma without spirometry." If you'd like a refresher on interpreting spirometry, this 2014 AFP article on "A Stepwise Approach to the Interpretation of Pulmonary Function Tests" provides a helpful overview.

If your office doesn't have spirometry, however, a simple peak flow meter can still be useful in making an asthma diagnosis. A patient with as-yet-undiagnosed asthma won't know their personal best peak flow value, but apps like Calculate by QxMD or MDCalc can estimate a personal best based on your patient's age, height, and gender. If a patient with chronic cough produces a peak flow less than 80% of that predicted value, empiric treatment for asthma is reasonable pending formal outpatient pulmonary function testing.

Managing an asthma diagnosis can feel overwhelming to patients, especially given the complexities inherent in managing and monitoring symptoms. Helping patients learn how to use their medications correctly is a critical early step. A sizable proportion of asthma patients do not use their metered dose inhalers (MDIs) correctly; providing written patient education material can help, but demonstrating how to use an MDI in the office improves patients' technique even more. Monitoring symptoms and peak flow readings is also important, since teaching patients how to monitor and interpret their peak flows can reduce urgent treatment visits for asthma.

Available online tools to help physicians monitor their asthma patient population include the Interactive Asthma Action Plan available from the Agency for Healthcare Research and Quality and the Association of Clinicians for the Underserved's Asthma Clinical Support Tool. Family Practice Management has a Disease Management Toolbox for Asthma which includes flow sheets and patient self-assessment surveys. There's an AFP By Topic on Asthma highlighting AFP's best content on diagnosis and treatment along with patient education materials. Using the search box on the Community Blog (upper right hand corner of this page) will display recent posts describing new studies about asthma management and treatment. Any of these resources might be useful links to add to your AFP Favorites page.

What resources do you find helpful to diagnose and care for patients with asthma?

Do statins benefit patients at low risk of cardiovascular disease?

- Kenny Lin, MD, MPH

There has been no shortage of recent guidance on statin use for the primary prevention of cardiovascular disease (CVD). The American College of Cardiology / American Heart Association and the U.S. Preventive Services Task Force (USPSTF) disagree about the appropriate 10-year CVD event risk threshold at which clinicians should recommend statins - 7.5% and 10%, respectively - but both agree that the benefits significantly outweigh the harms. So what should clinicians make of the Medicine By the Numbers in the Nov. 1 issue of AFP, which gave a Red (no benefits) rating to statins in persons at low (less than 20% 10-year) risk of cardiovascular disease?

Dr. John Abramson calculated the numbers needed to treat (NNT) to benefit and harm based on data from the 2012 Cholesterol Treatment Trialists (CTT) meta-analysis and the USPSTF's 2016 systematic review. Excluding patients with existing cardiovascular disease or a greater than 20% 10-year CVD event risk, the results showed no statistically significant mortality benefit, but 1 in 217 persons avoided a nonfatal myocardial infarction and 1 in 313 avoided a nonfatal stroke. On the harms side of the scale, 1 in 21 persons experienced pain from muscle damage, and 1 in 204 developed diabetes mellitus as a result of taking statins. Dr. Abramson acknowledged that his conclusion of "no benefit" relied on value judgments about the importance of these harms compared with cardiovascular events prevented:

In summary, studies have found no significant overall mortality benefit with statin therapy in low-risk patients, as well as no reduction in the risk of serious illness overall and very small benefits for nonfatal heart attack and stroke. Statins also appear to cause diabetes. Although this is uncommon, diabetes may occur more often than the prevention of a heart attack or stroke in patients taking statins. ... With no mortality benefit, no reduction in serious illness, an approximately 1% chance of avoiding a nonfatal heart attack or stroke, a similar or greater chance of developing diabetes, and a one in 21 chance of muscle damage, it seems wiser to focus on lifestyle changes (such as adopting a Mediterranean diet, exercising, and not smoking) instead of cholesterol drugs in low-risk patients.

These findings are broadly consistent with a 2011 Cochrane for Clinicians that noted that because "most trials included large numbers of persons with known CVD, ... clear evidence of the effectiveness of statins to prevent a first cardiovascular event is lacking." Other Cochrane reviews have found that statins reduce all-cause mortality in patients with non-dialysis chronic kidney disease, but do not prevent dementia or cognitive decline. A previous AFP article summarized considerations for safe use of statins, which should be part of shared decision making discussions with patients when the benefits and harms are so closely balanced.