Making Sense of Blood Pressure Guidelines — What Happened in the 1930s Should Stay There

Christopher Labos, MD CM, MSc, makes sense of nearly 100 years of blood pressure recommendations.
www.medscape.com/viewarticle/second-thought-making…

-- TRANSCRIPT --
Blood pressure. If you're a primary care provider trying to do right by your patients, you might be understandably confused by the current mishmash of guidelines with different blood pressure targets. But as chaotic as things are, at least it's not the 1930s, when you might hear John Hay give a lecture to the British Medical Association and say, "The greatest danger to a man with high blood pressure lies in its discovery, because then some fool is certain to try and reduce it."

Yeah, he said that. But what happened in the 1930s stays in the 1930s. And now we can at least agree that we should be treating high blood pressure. But what's the goal we should be aiming for? This is On Second Thought.

We've come a long way since FDR was recording blood pressures of 200 and his doctor prescribed him barbiturates and massage therapy.

That s#$# don't fly no more. Over the past hundred years, we have become much more aggressive in treating blood pressure. Remember the Oslo study? It defined mild hypertension as a blood pressure between 150 and 180 mm Hg. Now, those numbers send people screaming to the emergency room. So, let's acknowledge that things are substantially better than they once were. Let's agree on that and we can start to heal this nation again.

Before we get into the numbers, when we're treating blood pressure, let's make a few points about measuring it. Obviously, to treat something, you have to measure it properly. Two recent trials have illustrated that these details matter a lot.

The Cuff(SZ) randomized crossover trial — and it took me a minute to realize that Cuff(SZ) meant cuff size, so bravo, Ishigami et al — showed that picking the wrong cuff size could affect BP measurements by 4.5 points if you were one size off. If you were two sizes too small, you overestimated BP by almost 20 points.

Add on here another recent study, the ARMS crossover randomized clinical trial, looking at how arm position affected BP measures. If the arm was resting on your lap or hanging by your side, that overestimated blood pressure by 4 and 6.5 points. So sometimes you have to remember the fundamentals: cuff size, arm position — it might make the difference between increasing or maintaining the patient's meds.

But on to the main show. What numbers should we be aiming for? We no longer live in the "BP 200, the president's going to have a stroke" world of the 1940s, and even a BP of 150 is considered quite high these days. Studies like the MRC trial, INVEST, and SPRINT have pushed BP targets ever lower. SPRINT, in particular, randomized patients to a blood pressure target under 120 systolic vs under 140 systolic, and the under-120 arm won out with fewer cardiovascular events and lower all-cause mortality.

Pretty definitive slam dunk. But the more intensive treatment came with more hypotension, syncope, and kidney injury, because there is no free lunch in medicine. And ditto with BPROAD, just published in The New England Journal of Medicine and presented at the American Heart Association annual meeting. A diabetic population randomized to 120 vs 140 as a BP target showed that more aggressive treatment was better.

Fewer cardiovascular events, like stroke, but no mortality difference, and more hypotension. So a cardiovascular benefit at the cost of more side effects. Now, like all cardiologists, my motto is "Save the heart and screw the kidney." But if you do care about the other organs in this meat sack that we call a human body, the question you need to wrestle with is, how much do you value cardiovascular protection vs how willing are you to tolerate side effects?

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www.medscape.com/viewarticle/second-thought-making…