High blood pressure: When drugs do more harm than good

Having high blood pressure is a big deal. According to the massive, long-running and ongoing Global Burden of Disease study, hypertension – the medical term for elevated blood pressure – is the leading risk factor contributing to the burden of disease in the world, across both developed and developing countries.

High blood pressure also kills: it’s the leading cause of death in the world.

And the definition of ‘high blood pressure’ might surprise you: your risk of cardiovascular disease starts rising once your systolic pressure gets above 115 mmHg, or your diastolic above 75 mmHg.

So it’s no surprise that blood pressure-lowering medications, or antihypertensives, are one of the most commonly-prescribed drugs in Australia, and indeed in most Westernised countries, and that doctors are quick to prescribe them when they identify high blood pressure in their patients.

But a study published in JAMA Internal Medicine in October 2018 confirms previous research that informs clinical practice guidelines in the UK: people with mild hypertension (untreated blood pressure of 140/90-159/99 mm Hg) who don’t have other risk factors for cardiovascular disease, do not benefit from taking blood pressure-lowering medication, and are at risk of being harmed by it.

The study followed over 19 000 people with mild (also known as Stage 1) hypertension and no history of cardiovascular disease (CVD) or CVD risk factors for an average of 5.8 years. The researchers did not find any evidence that blood pressure-lowering medications reduced the risk of developing cardiovascular disease, or of dying.

On the other hand, the drugs resulted in a range of adverse reactions (‘side effects’) including excessively low blood pressure (hypotension), syncope (fainting, which can lead to head injury and bone fractures), electrolyte abnormalities and acute kidney injury.

The researchers calculated the risk of suffering these side effects using an extremely useful measure called ‘number needed to harm’, or NNH. NNH essentially describes how many people have to take the drug for one person to suffer the specified side effect. For example, an NNH of 100 means that for every 100 people taking the drug, one will experience the adverse reaction.

NNHs at 10 years for antihypertensive drugs in this low-risk group of mild hypertensives were:

• Hypotension – ₄₁
• Syncope – 35
• Electrolyte abnormalities – 111
• Acute kidney injury – 91.

That’s a lot of people suffering dizziness, fainting, messed-up blood chemistry and kidney damage, for no good reason.

The study describes one type of harm – an increased risk of adverse reaction. Borrowing from Catholic theology, I call this a ‘sin of commission’ – an action taken by a medical profession that causes harm to the patient. However, there is a second type of harm which results from prescribing drugs for a condition that is mostly caused by lifestyle factors – a ‘sin of omission’ in which the professional fails to disclose vital information to the patient.

A bit of background. I come from a family of hypertensives. Both my late father and my mother (now 86) were on blood pressure-lowering medications from quite an early age; my mother was first prescribed antihypertensives in her late 30s, and my father was in his 40s.

Over the years, I watched both my parents’ various and sundry doctors fiddle with their medications – adding additional drugs, increasing dosages, swapping one drug for another – without ever bringing the blood pressure of either one into a normal, healthy range.

What was the outcome of this intensive drugging? My father developed type 2 diabetes – a condition which two of the blood pressure drugs that he took, thiazide diuretics and beta blockers, are suspected to raise the risk of – and died of a heart attack. My mother’s blood pressure averages an eye-popping 180/100, despite her religiously taking three antihypertensive medications.

But in the nearly 5 decades since my mother was first prescribed blood pressure-lowering medications, and in the 3 decades that my father lived after his first antihypertensive prescription, not a single doctor ever sat either of them down and explained the real causes of high blood pressure to my parents, and what they could do about them.

My parents were not told that their Western-style diet, high in animal flesh and dairy products, was impairing their endothelial function and hence, raising their blood pressure and cardiovascular risk.

Although my mother was counselled to lower her salt intake, she wasn’t told that 80 per cent of the sodium consumed by Australians is contained in processed foods, rather than added during cooking or at the dinner table; she wrongly believed that throwing away the salt shaker would protect her from excess sodium.

Neither of my parents was told about the benefits of exercise or mindfulness/meditation practices for lowering blood pressure.

My mother, a chronic insomniac, was never told just how badly sleep deprivation impacts on blood pressure, nor was she given effective advice on improving her sleep quality.

Instead of accurate and empowering information about their condition and the daily lifestyle choices they could make to ameliorate it, they were given the usual explanations for their condition, which in my opinion are simply excuses: high blood pressure is genetic (twin studies show that only 30-50 per cent of the variance in blood pressure readings is related to our genetic inheritance, with environmental factors – chiefly lifestyle choices – accounting for the remainder); it’s normal for blood pressure to go up with age (it’s not – in cultures in which salt intake is low, such as Papua highlanders and Yanomamo Indians, hypertension is non-existent and the blood pressure of elders is the same as in the young).

And of course, they were told that they would have to take their blood pressure drugs for the rest of their lives.

This kind of prescribing amounts to writing a permission slip – a free pass for sick people to continue the diet and lifestyle habits that made them sick in the first place, while perpetuating the myth that artificially lowering blood pressure using drugs that interfere with various regulatory mechanisms in the body, provides the same protection against cardiovascular disease that people with naturally low blood pressure enjoy.

The study in JAMA Internal Medicine clearly demonstrates that people with blood pressure up to 160/100 but without other cardiovascular risk factors do not benefit from being on blood pressure medication. While those with severe hypertension (160/100 or above) do experience some reduction in cardiovascular disease and overall mortality risk, they would obviously benefit even more from a comprehensive Lifestyle Medicine approach incorporating diet, exercise, sleep and mindfulness practices.

Do you have high blood pressure? Worried that you might be taking drugs that incur more risks than benefits? Apply for a Roadmap to Optimal Health Consultation today, and let’s take the pressure down!