November 26, 2017

Down, Down, Down

         The most important recent development affecting older patients, without a doubt, is the issuance of new guidelines for the diagnosis and treatment of high blood pressure. The Wall Street Journal proclaimed “Nearly Half of US Adults Have High Blood Pressure Under New Guidelines,” and venerable health columnist Gina Kolata of the NY Times wrote: “The nation’s leading heart experts on Monday issued new guidelines for high blood pressure that mean tens of millions more Americans will meet the criteria for the condition, and will need to change their lifestyles or take medicines to treat it.The report, which took me a while to track down and read since most of the references are to summaries of the report or commentaries on the report but not to the actual document, is 175 pages. It was issued or endorsed by eleven organizations, whose initials actually form part of the name of the report: its full name is the “2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPCNMA/PCNA Guidelines for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults.” The subtitle is: “A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines.” Now that I’ve had a chance to digest this—what should we make of it?
         I remember the day in 1991 when JAMA published the results of the “SHEP” trial, a study of the treatment of isolated systolic hypertension in the elderly that upended what I’d been taught in medical school. Gone was the belief that high blood pressure was good for older people because they needed greater force to push blood through their stiff arteries; suddenly, there was compelling evidence that high blood pressure was dangerous—it caused strokes and heart attacks. Keeping the systolic blood pressure below 160 reduced the risk of stroke by 36 percent and the risk of a cardiac event by 27 percent. Overnight, the practice of medicine changed.
         To be sure, there were skeptics. Wouldn’t lowering the blood pressure cause older people to become dizzy and to faint? Just how far were we supposed to lower blood pressure anyway? But to me and many others, the choice was clear. Stroke was one of the worst fates that could befall older patients: sometimes it killed them, but more often, it left them impaired, often profoundly, significantly diminishing the quality of life.
         But I also remember a book by physician and historian of science, Jeremy Greene, published in 2008 and called Prescribing by Numbers: Drugs and the Definition of Disease. Greene argued persuasively that the pharmaceutical industry has a vested interest in lowering the cut-off for treatment of a variety of chronic conditions, such as hypertension, high cholesterol, and diabetes. Defining “pre-diabetes” as a real condition warranting treatment or repeatedly dropping the threshold for treating cholesterol with statins had clear implications for the drug companies: they would sell more pills. More volume, more revenue, more profits. So are the new guidelines just another instance of “diagnosis creep,” a way for Pharma to make more money?
         It’s important to realize that what tipped the scales for the guideline writers, what’s different now from the last time they wrote a guideline, three years ago, is the 2015 “SPRINT” study (Systolic Blood Pressure Intervention Trial), a randomized trial of high risk patients over 50 to either a systolic blood pressure target of 140 or 120. The study, which was reported in the New England Journal of Medicine, found a 25 percent reduction in cardiovascular events (such as stroke or heart attacks) when physicians tried to reduce the blood pressure to the lower value.
         As Gilbert Welch of the Dartmouth Institute, co-author of Overdiagnosed: Making People Sick in the Pursuit of Health (2012) and Less Medicine, More Health (2016), commented, that 25 percent sounds pretty good, but it’s the relative risk reduction. In fact, the rate of cardiac events fell from 8 percent in one group to 6 percent in the other—an absolute difference of only 2 percent. Or, looked at differently, 92 percent of people in one group and 94 percent of people in the other group did just fine. Suddenly, the impressive results don’t look quite so impressive. Moreover, all these patients were already at increased risk of cardiovascular disease because of other factors such as cigarette smoking or diabetes. Presumably, had the same study been carried out in people of average or lower risk, the benefits would have been correspondingly smaller.
         So if the new guidelines are based predominantly on the findings from one study, and the one study isn’t quite as compelling as it seemed at first glance, what should we make of the new recommendations? Should we really treat everyone with a systolic blood pressure over 120 who has at least a 10 percent risk of cardiac disease in the next decade? 
         The answer, I think, is yes, but with caveats. First, the guideline writers are at great pains to insist that blood pressure be measured the way it was measured in the SPRINT trial—in a way that it’s almost never measured in the doctor’s office, namely after sitting quietly for five minutes and averaged over three readings. They also advocate use of home monitoring to confirm (or refute) the diagnosis of high blood pressure, as well as to guide medication adjustment once treatment is started. Next, physicians need to be prudent about what medications to use if they’re going to embark on pharmacologic treatment. We have ample numbers of cheap, effective medicines that have been around for years, such as diuretics and beta blockers, and these should be tried before pricier medicines. Finally, both physicians and patients need to be vigilant about medication side effects, which means doctors need to tell their patients what to look for, patients need to report their symptoms, and doctors need to change course if symptoms develop. In addition, non-pharmacologic treatment should be attempted, including exercise, weight loss, and a low salt diet. If we follow all these steps, we can be confident we will be changing how we deal with blood pressure because it’s what’s best for patients, not because it’s what’s best for the pharmaceutical industry.

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