Gabor Szendi:
About high blood pressure and the benefits of screening

Medicine, the media, and the average person convinced by them, stubbornly believe in the usefulness of screening. However screening is a double-edged weapon because it can reveal something that needs to be treated - partly because the doctor says so, and partly for the patient's peace of mind. Who can live with a diagnosis that works like the sword of Damocles?

 

 

The white coat effect

Take blood pressure measurement as an example. In the case of blood pressure measured in medical clinics and hospitals the so-called white coat effect should always be taken into account. The phenomenon was recognized by Scipione Riva-Rocci, who in 1896 further developed the blood pressure monitor (Brunström and Carlberg, 2018). In the 1980s, researchers proved that the appearance of a doctor raises blood pressure and heart rate significantly. This has serious consequences. One study showed that 30-40% of patients treated with hypertension have normal blood pressure if not measured by a doctor (Mancia et al, 2011). That is, many patients took unnecessary antihypertensive drugs in this study. In another, 37% of those diagnosed with persistent hypertension were found to have been treated for hypertension due to a white coat effect (Muxfeldt et al, 2005). Some studies suggest that more anxious people become so because they are easily tense in emotionally stressful situations, but others studies find that many white coat reactions are specific to the physician, and in other situations, such people do not respond with hypertension. Many people's blood pressure increases upon measurement because they are expecting to have high blood pressure. I remember a male patient who was so afraid of the results of his blood pressure measurement that he already had extreme results when he measured it alone at home. Fearing the consequences of the examination, he hid from the occupational doctor for years, and then came to me when the next examination seemed inevitable. It's a real, paradoxical situation: how to measure someone's true blood pressure, if it always goes up, approached with a blood pressure monitor? I suggested I taught him how to relax, and in order to perform well in the doctor's office later, put a blood pressure monitor on him, to get used to it. After a couple of times I suggested that I measure his blood pressure in a relaxed state, but of course I wasn't going to tell him. Of course I told him it was normal. We do not know in how many such cases it is found that the patient has "high blood pressure," and treatment is started. I understand, of course, that in a medical office, you can't get the right result out of a patient through relaxation stratagem, but the problem still remains and questions the usefulness of blood pressure screening.

Home measurements also mislead many. People usually measure by stopping what they were doing, picking up their blood pressure cuffs and starting measurement. I have tested many times that if I sit still and calmly after the first measurement, thinking of nothing, and then take my measurement for a second time, I get a value lower by 10-15 mmHg, because that is the value measured in the true resting state, and blood pressure flexibly follows not only physical activity but also emotional and mental changes. In itself, tension can raise blood pressure.

However, there is real hypertension

But of course, many people have higher blood pressure than the recommended targets, even if we exclude the white coat effect. According to the latest recommendations of the American Cardiology Society, blood pressure should be below 120/80 at rest, this is the "normal" value. These values are derived from decades of follow-up studies. According to a large study of 1.2 million people in 2014, for example, normal blood pressure reduces the risk of bleeding strokes by 10% in relation to the general population, however, hypertension increases it by 30%. The difference is a 40% risk, but this is a relative risk! If we count it as an absolute risk, we find that with normal blood pressure (in this study), 7 out of 10,000 people had a bleeding stroke, and with hypertension 9 had a bleeding stroke. So the risk difference is actually 0.02% a year. People with hypertension have a 50% greater chance of sudden cardiac death, but in absolute terms this is again a 0.02% risk difference. Of course, when comparing people with very high blood pressure at different ages to those with low blood pressure, coarser numbers come out (Rapsomaniki et al, 2014). At the same time, it is food for thought as to what extent high blood pressure is responsible for these risks, and to what extent those factors, among others, can cause high blood pressure. For example, in a large study, people with normal blood pressure who were not affected by any other risk factors (smoking, diabetes, and high cholesterol) also had a high chance (40% men, 30% women) of cardiovascular disease or death (Wilkins et al, 2012). This can be contrasted with people having all risks: by the age of 85, there is a 60% and 56% chance of having a cardiovascular patient die through this type of death. If we look at it this way, the difference is not that big. So the person who has all the risk factors according to cardiology, and burns the candle at both ends, is only 20% more likely to have heart disease? Then these risk factors explain only a fraction of the risk, and yet they are the focus of medicine.

Is high blood pressure disease a symptom, or what?

It all depends on who we ask. Doctors say it's a disease. When we ask a physiologist, then this is a symptom that can have many causes, from stress through hardened blood vessels to narrowing of the renal artery. According to Ray Moynihan and Alan Cassels, the authors of "Selling sickness," this is a risk factor sold as a disease (Moynihan and Cassels, 2005). What is the risk factor for hypertension? Heart disease and cardiac death, kidney damage, cerebral hemorrhage, vascular dementia, retinal damage, etcetera. However, there may already be some uncertainty about what causes what. In part, that which causes hypertension, is explained by hypertension. For example, hardening of blood vessels is one of the causes of high blood pressure, which can then rupture stiffened blood vessels. And if we only treat one of the risk factors, high blood pressure, , what can we get away with? How much does the risk of the listed consequences decrease? As I quoted above, people with normal blood pressure may have heart disease or stroke. That is, a little self-deceptive - but a good deal - because lowering blood pressure does not solve the real problem.

Absolute and relative risk

Let's get to know the most primitive pharmaceutical trick we run into every day, but don't know about. Let's say 2 out of 1,000 people die of a disease in 5 years. The pharmaceutical industry comes up with a drug it claims will reduce disease-related death by 50%. In reality, this means that only 1 in 1,000 people will die. The 50% relative risk reduction is the ad text. But what is the absolute risk reduction? That is 0.001%. So as not to merely theorize, let's take the protective effects of aspirin. A 2009 study found that taking aspirin reduces the risk of major cardiovascular events (infarction, thrombosis) by 12%. In absolute numbers, it reduced the number of events from 0.23% to 0.18% per year. That is, the 12% risk reduction is 0.05% in reality: from 10,000 people who take aspirin, the number of adverse cardiovascular events is lessened by five (Baigent et al, 2009). The risk of aspirin-induced internal bleeding is about the same, meaning neither protection nor risk is too serious. The bigger problem is that aspirin users think they are protected and may not do anything for better protection.

About lowering blood pressure

While not questioning the dangers of hypertension, the benefit of taking antihypertensive drugs is questionable.

Erica Wallis et al. compared two imaginary patients. Both have a blood pressure of 150/96. Any doctor would immediately prescribe an antihypertensive. But one patient is a 35-year-old woman with no risk factors, and the other is a 65-year-old man who smokes. The first patient has a 2.5% chance of having heart disease in 10 years, the latter has a 50% chance. Medication results in a 25% reduction in relative risk for both. However, the absolute risk reduction is only 0.6% for the first patient and 12.8% for the second patient (Wallis et al, 2002). That is, it is questionable whether it is worth giving the first patient medication, or exposing her to its side effects.

Let's look at the benefits of lowering blood pressure in general, based on a meta-analysis of 74 studies published in 2018 (Brunström and Carlberg, 2018). With systolic blood pressure greater than 160 mmHg, the risk of cardiac death was reduced by 15% as a result of antihypertensive therapy. We could have expected better if blood pressure was really the main problem. But just this slight improvement shows that lowering blood pressure has not changed much in the state of people with heart disease. But you could justifiably say that we should also appreciate this small decrease. However, if we calculate the actual risk reduction in absolute terms, in reality it is even smaller: compared to 1.57% of untreated people's deaths due to heart disease, 1.35% of people treated with antihypertensive drugs died. That is, taking antihypertensive drugs reduced the risk of cardiac death by 0.22%. For stroke, the absolute risk difference between treated and untreated hypertensive people is 0.26%, at the expense of untreated people. If I take only people with a blood pressure higher than 160 mmHg, there is a 31% reduction in risk due to medication, but this is only 0.44% in absolute risk.

Is it worth taking antihypertensives?

I premise that these pages are not medical advice, and I do not want someone's tombstone to say, "Szendi told me not to take it." We are just thinking here, and then everyone must draws their own conclusions about risk.

First, over the age of 80, it has been shown that high blood pressure significantly reduces the risk of dementia. This is obviously because of the better blood supply to the brain (Corrada et al, 2017).

As we have seen, lowering blood pressure generally has a modest benefit. The question is, what about the side effects of the drugs used? Are they doing more harm than good?

Common symptoms of antihypertensives include dizziness, headache, diarrhea, frequent urination (calcium channel blockers (CCB), diuretics), dry cough (angiotensin converting enzyme inhibitor (ACEI)) (Olowofela and Isah, 2017). These are "just" unpleasant symptoms, but beta-blockers and thiazide diuretics increase the risk of diabetes by 20-50% (Marino, 2009) Although rarely ACEIs can cause kidney failure, inflammation of the pancreas, decrease in white blood cells, and after 10 years of use, increase the risk of lung cancer by 30% (Hicks et al, 2018). Angiotensin receptor blockers (ATB) increase the risk of heart attack by 19% -36% and the risk of stroke by 13% -48% (Verma and Strauss, 2004). In one study, CCBs increased the risk of infarction by 60% (Psaty et al, 1995), and the risk of stroke by 230% (Klungel et al, 2001). Based on a meta-analysis of 16 studies, Lindholm et al recommend cessation of beta-blockers in blood pressure management (Lindholm et al, 2005), as they increase the risk of stroke from 12% to 228%, to varying degrees in different studies. They estimate that 125,000 strokes in 5.5 years could have been prevented in the old European 15 Member States if beta-blockers were discontinued in primary hypertension. Because a drug normalizes only blood pressure in a fraction of patients, they often combine more than one. Diuretic-combined CCBs doubled the risk of myocardial infarction (Boger-Megiddo et al, 2010).

However, no one should throw their medication down the toilet, partly because fish will lower their blood pressure, and partly because sudden withdrawal can cause great trouble.

Anyway, it's a difficult task to estimate which is the bigger problem: hypertension, or how to treat it. The way out of the dilemma is that the paleo diet, for example, lowered blood pressure by 9/5 mmHg in two weeks, and I know from daily practice that many people have had their blood pressure normalized by switching to paleo. The paleo or lowcarb diet does not actually "treat" blood pressure, but slims and reduces inflammation in the body, thereby widening blood vessels, and improving heart function. This should be promoted by medicine, God knows why Doctors only believe in more drugs. Lifestyle sicknesses should be cured by lifestyle changes.

 

References

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Boger-Megiddo I, Heckbert SR, Weiss NS, McKnight B, Furberg CD, Wiggins KL, et al. Myocardial infarction and stroke associated with diuretic based two drug antihypertensive regimens: population based case-control study. BMJ. 2010;340:c103

Brunström M, Carlberg B. Association of Blood Pressure Lowering With Mortality and Cardiovascular Disease Across Blood Pressure Levels: A Systematic Review and Meta-analysis. JAMA Intern Med. 2018 Jan 1;178(1):28-36.

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Marino, MT: Drugs that can worsen diabetes control. Diabetesselfmanagement.com 2009

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