The war over the new blood pressure guideline is not a fake war or a childish dispute. It is a real war over genuine differences in how we should think about health and disease and prevention.

The publication last November of the new US blood pressure guideline sparked a vigorous and important debate. A central part of this debate is whether the new guideline went too far, since millions of people who were deemed to have “normal” blood pressure were labelled as “hypertensive.”

All at once the number of US adults  labelled as “hypertensive” jumped from 72 million to 103 million, which translates to an increase from 31.9% to 45.6%, according to one reasonable estimate.

In a recent blog post one clinical trial expert, Milton Packer, sensibly pointed out that “the whole idea of a numerical threshold was silly. The risk associated with hypertension is not binary.

It does not become real when you exceed a certain number, and it does not fully subside when you are below it. The risk is continuous; the higher the number, the higher the risk.”

He further observed that the new guideline relies on data from the highly controversial SPRINT trial, “but no one really understands the blood pressures in that study” and the new guideline “applies its recommendations to people who were not even represented in the SPRINT trial.”

Packer then focused on one part of the guideline debate. On one side two medical specialty groups, the American Heart Association and the American College of Cardiology, (who developed the new guideline) broadly endorsed the new guideline.

On the other side, two primary care groups, the American Academy of Family Physicians (AAFP) and the American College of Physicians (ACP), refused to accept the new guideline. Instead, the AAFP and ACP published their own guideline for adults over age 60 recommending that physicians start treatment only in patients with systolic blood pressure of 150 mm Hg or above.

In a statement the AAFP explained that the AHA/ACC guideline was not based on a rigorous systematic review of the evidence. They also expressed concern about the strong reliance on the SPRINT trial and conflicts of interest among the committee members of the AHA/ACC guideline.

By way of explaining this divergence Packer notes, undoubtedly correctly, that “primary care physicians really dislike it when specialists tell them what to do.”

But Packer misses why this is not a trivial debate. He says that he is “entertained” by the claims that the war is “fake” “since there is no magic number that describes the risk associated with high blood pressure, there has been nothing to fight about.”

He asks: “Why do children get into mud fights?” His answer: “Because they enjoy acting like children.”

I agree with Packer that there is no one simple answer to this question. There will never be a “magic number” that is proven to be “right” by science. Any threshold inevitably involves tradeoffs and compromises.

But I couldn’t disagree more that this is a silly mud fight between children. I think this dispute is deadly serious and is packed with meaning.

On the one hand, the specialist view represented by the AHA/ACC guideline weaponizes the medical system to seek and destroy disease. High blood pressure, in this view, is an enemy that must be wiped out at any cost. But this view fails to sufficiently account for the inevitable collateral damage.

It downplays the adverse side effects of treatment (or overtreatment), and it almost never takes into account the adverse effect of telling an otherwise healthy people that they have a serious disease. It focuses on the reduction of relative risk and brushes off the small reduction in absolute risk. This is why the NNT (number-needed-to-treat) increases as the absolute level of risk goes down.

For specialists these limitations are not a big deal, since they are focused on the disease and not the entire patient. (Of course I am aware that the vast majority of specialists are not insensitive brutes, but this is also an inescapable element of specialisation.) Paternalism is ubiquitous in medicine, and specialists are far more susceptible than primary care doctors.

On the other hand, the primary care physicians look at blood pressure within the larger perspective of the whole patient and the public health context. This doesn’t mean that primary care doctors aren’t aware of the relationship between blood pressure and risk, or that they are uninterested in cardiovascular risk prevention.

But this is not their exclusive interest, and they are finely attuned to the adverse effects of overtreatment, since they are the ones who will deal with the patients who fall when their blood pressure drops too far or who mix up all the pills they nearly invariably take as they grow older.

From a primary care perspective it is crazy to think that nearly half the adult population has a disease that needs to be treated. In case you haven’t been looking, our healthcare system is already bigger by far (by percentage of GDP) than any other healthcare system in the world. Does it really need to grow larger? Is this what we want to do, turn everyone into a patient?

Furthermore, there is a far more urgent blood pressure problem that is not being adequately addressed, even by the standards of the American Heart Association. According to the AHA’s own recently released statistics, only 84.1% of people with hypertension (under the old definition) were aware of their condition, only 76% were under current treatment, and barely half (54.4%) had their hypertension under control.

Why focus on bringing in even more and lower risk people into the “hypertension” diagnosis when there are still so many higher risk people who are being inadequately identified and treated?

There is a another important perspective that needs to be considered here. This perspective is not about specialty versus primary care but is instead about medical care (primary or specialty care) versus public health.

From the public health perspective it is inevitably a losing proposition and a rearguard action for doctors to treat mildly elevated blood pressures with medicine or even individual lifestyle advice.

Instead we need broad public health measures to help bring about a culture that encourages and steers people toward lifestyles that incorporate healthful food and exercise habits. In this case the focus is on doing something positive and healthy, rather than fighting a disease.

As I’ve asked before, do we really want to turn the entire world into a hospital? No matter how it is dispensed, taking a pill is not a positive experience. By contrast, cycling to work, to take a favorite example of mine, can be a life-affirming experience for many.