Knowing your blood pressure could save your life

“I feel fine,” she says, brushing the crumbs off her top. “What’s the fuss for?”
I have dashed to my patient’s bedside after being summoned about her blood pressure of 220/105 mm Hg, thrice checked. In my head, I am running through a list of catastrophic consequences, including a brain haemorrhage, that could destroy her life in an instant.
The hospital doesn’t have an intensive care unit. How and where will I evacuate her? If a medication patch doesn’t work, can we run an infusion? At 82, she looks a decade younger but has she written an advance care directive in case she cannot make decisions for herself?
While the nurse and I act, the patient happily says at her age no one cares about blood pressure. Having seen a friend survive a hypertensive brain haemorrhage but left with lifelong disability, I disagree.
But her blithe response reminds me of the relevance of guidelines issued by the National Hypertension Taskforce of Australia.
Hypertension, defined as a blood pressure over 140/90, is by far the leading risk factor for preventable deaths. About 10 million people around the world, 25,000 of them in Australia and 75,000 in the UK, die annually from hypertension-related conditions such as stroke, heart and kidney disease and vascular dementia.
High blood pressure is common enough to have entered the vernacular – as in “this person raises my blood pressure”. But of the one in three Australians that has hypertension, half don’t even know it. Of the ones who do, just a third are treated effectively, matching rates in the UK and the United States but faring worse than South Korea and Canada.
We ignore hypertension at our peril because it is a silent killer. Unlike many other chronic conditions, hypertension seldom causes symptoms, afflicts young and old, and is highly treatable. Indeed, for a lethal condition, its image as a benign bystander poses a major public health dilemma.
If you are hypertensive, chances are you don’t even know it. And if you know you are hypertensive, chances are you don’t know if it’s well controlled.
Here are some key messages worth heeding.
When a friend recently reported palpitations, I wanted to know her usual blood pressure. She guessed one number was 110 and hesitantly asked if that might be the “top or bottom” reading. Either, I rued, with very different consequences. Luckily, an ambulance arrived in time to treat her impending stroke.
Nearly 90% of the population sees a GP at least once a year. Other settings including pharmacy, allied health and community health centres provide ready opportunities to check blood pressure. I advise all my patients to keep a record of their ECGs and blood pressure readings because the trend is more useful to doctors than a spot measure.
Like most of my patients, my parents have difficulty remembering their blood pressure. “Usually OK” is too vague a reassurance, so I decided one fix was to get them a home-monitoring device before noticing that it rarely left its box.
I was surprised to read that four out of five automated devices sold online are not validated, meaning they have not been properly tested for accuracy. Even the stamp of health regulatory authorities may not be enough. Cuffless wearable devices are popular but not yet recommended until their accuracy has been confirmed.
Use an online resource to check that your device fits the bill.
Note that home monitoring works best after getting the diagnosis right, either via high-quality office measurement or the gold standard method of 24-hour ambulatory monitoring, which is especially useful for those who experience “white coat hypertension”.
Most people diagnosed with hypertension will have it despite lifestyle changes and thus should be prescribed medication alongside diet and exercise. It is a rite of passage for young doctors to be dismayed at how a “perfect” blood pressure reading in the hospital evaporates in the community, thus setting up a revolving door of complications.
A common example involves diuretics, a cheap and remarkably effective class of medication to treat hypertension. The problem with diuretics is that young people often don’t like them because of the urge to urinate frequently and the elderly reject them because they are rendered incontinent or at risk of falls when rushing to the bathroom. Other antihypertensive drugs are associated with side effects including dizziness, insomnia, sexual dysfunction, cough and nausea.
No wonder between a quarter to half of people simply ignore their prescription. With over 100 different drug preparations, treating high blood pressure is a skill that involves trial and error and an understanding of the individual.
While most people are well-managed in primary care, patients with refractory (hard to treat) hypertension warrant a specialist referral because a substantial proportion may have treatable adrenal gland pathology, an unappreciated and hence, untreated problem.
Compared with cancer screening and flu vaccination, modelling in the United States indicates that effective treatment of hypertension would prevent the greatest number of deaths. It is astonishing to think that if the prevalence of hypertension were reduced by just 25%, and if all those diagnosed were effectively treated, the savings would exceed $90bn in GDP.
The Hypertension Taskforce aims to achieve a 70% blood pressure control rate in Australia within this decade. This is an ambitious task but not unachievable. Population screening, value-based medical care, and community awareness all matter but there is an important question for every individual: if you had high blood pressure, would you even know it?
It is the case with many diseases to hear the lament “if only I’d known”. If knowledge is power, knowing your blood pressure is the kind of knowledge that could save your life.