Antihypertensives may benefit people with normal blood pressure

Evelyn Lewin

4/05/2021 12:29:52 PM

But experts worry about the potential real-world benefits and harms of putting ‘millions more’ people on these drugs.

Doctor taking blood pressure
Study authors say the findings show the need to steer guidance on antihypertensives away from basing the decision solely on blood pressure levels.

The benefits of commencing an antihypertensives in patients with hypertension are well documented.
But patients with normal or high-normal blood pressure may also experience cardiovascular benefits in taking these medications.
Such are the findings of new research published in The Lancet.
The study included almost 345,000 people from 48 randomised clinical trials of varying pharmacological blood-pressure-lowering medications.
For the meta-analysis, participants were separated into two groups: those with a prior diagnosis of cardiovascular disease, and those without.
These were then subdivided into seven groups based on systolic blood pressure levels, ranging from less than 120 mmHg to 170 mmHg and above.
Over an average of four years’ follow-up, 42,324 participants had at least one major cardiovascular event (heart attack, stroke, heart failure, or death from cardiovascular disease).
‘On average, a 5 mmHg reduction of systolic blood pressure reduced the risk of a major cardiovascular event by about 10%; the corresponding proportional risk reductions for stroke, heart failure, ischaemic heart disease, and cardiovascular death were 13%, 13%, 8% and 5%, respectively,’ the authors wrote.
They say the 10% reduction in risk of major cardiovascular events occurred ‘irrespective of previous diagnoses of cardiovascular disease, and even at normal or high-normal blood pressure values’.
‘These findings suggest that a fixed degree of pharmacological blood-pressure-lowering is similarly effective for primary and secondary prevention of major cardiovascular disease, even at blood pressure levels currently not considered for treatment,’ the authors wrote.
Co-author Zeinab Bidel from the University of Oxford says this finding shows the need to steer guidance on taking antihypertensives away from basing the decision purely on blood pressure levels.
‘It is important that people are considered for blood-pressure-lowering treatment based on their cardiovascular risk, rather than focusing on blood pressure itself as a qualifying factor for or target of treatment,’ Dr Bidel said.
‘We must provide well-rounded guidelines to lower risks for cardiovascular disease that include exercise, nutrition, smoking cessation and, where appropriate, medication.’
The study’s lead author, Professor Kazem Rahimi from the University of Oxford, echoes that sentiment.
‘This new and best-available evidence tells us that decisions to prescribe blood pressure medication should not be based simply on a prior diagnosis of cardiovascular disease or an individual’s blood pressure level,’ Professor Rahimi said.
‘Instead, medication should be viewed as an effective tool for preventing cardiovascular disease in people at increased risk of developing heart disease or stroke.
‘Clinical guidelines should be changed to reflect these findings.’

Professor Rahimi does not wish to be prescriptive, however.
‘We’re not saying that everyone must begin treatment,’ Professor Rahimi said.
‘The decision will depend on an individual’s risk factors for developing cardiovascular disease, the potential for side effects and patient choice.’

Even people with normal or high-normal blood pressure may benefit from taking antihypertensive drugs, according to the research.

The authors note the study had limitations, and that it did not specifically examine potential side effects of treatment.
Professor Nicholas Zwar, a GP and member of the National Heart Foundation of Australia’s National Blood Pressure and Vascular Disease Advisory Committee, raised concerns about a number of issues.
He told newsGP the fact the authors did not measure a range of other outcomes may prove problematic when applying this advice clinically.
‘They’ve measured all-cause cardiovascular death, they’ve measured cardiovascular events like coronary artery disease, stroke, et cetera, but they haven’t looked at other diseases,’ he said.
‘And we know from other research that if people, particularly older people, are put on antihypertensive medicines and you seek out a lower [blood pressure] target, you will get some people who will have acute kidney injury and some people will have more falls.’
Professor Zwar also questions the reduction in mortality risk.
‘If you look at all-cause mortality, it crosses no effect,’ he said.
‘So though the cardiovascular risk seems to decrease in both people with [and without] previous cardiovascular disease … the all-cause mortality is not significantly lower.
‘And even the cardiovascular disease mortality isn’t lower in everybody; it’s lower in some age groups, but not all age groups.’
Professor Zwar believes that needs to be taken into consideration when analysing the data.
‘If you’re not actually reducing deaths, that’s to be borne in mind as well; you can be reducing the thing you’re interested in – cardiovascular disease – but if you’re not actually having an overall benefit on mortality, you’ve got to keep that in mind as well,’ he said.
Professor Zwar is also concerned about promoting the idea that the only way to lower blood pressure is through medication.
‘There’s a tendency to think that the only treatment for high blood pressure is antihypertensive drugs,’ he said.
‘But there are other ways to reduce your blood pressure: by losing weight, drinking less alcohol, having less salt in your diet. It’s something to remember when looking at trying to lower blood pressure.
‘It’s not all about the drugs.’
While patients may be advised to make lifestyle changes to reduce their blood pressure, such advice can also lead to other positive health effects.
‘If someone is exercising and isn’t drinking alcohol to [the same] extent, that has a range of other health benefits that certainly is good for cardiovascular disease risk, but for other risks too, [such as] for cancer and reducing your risk of getting dementia, type 2 diabetes, et cetera,’ Professor Zwar said.
Professor Zwar is keen to note he is not saying the research was not thorough, nor is he questioning the validity of the findings, but he is unsure of the benefit of clinically applying those findings.
‘What would the real-world effects be of … having potentially millions more people taking antihypertensive medicines?’ he said.
‘Would that have these benefits? Maybe.
‘But would it also have more harms, and harms that this study hasn’t actually captured?
Professor Zwar says the study did find conclusive evidence that having lower blood pressure reduces your cardiovascular risk.
‘That’s not new,’ he said.
‘But whether that means you would get benefits from overall real-world benefits if a whole lot more people were taking blood pressure medicines, I’m not so sure.’
Log in below to join the conversation.

blood pressure cardiovascular disease heart disease

newsGP weekly poll What areas of healthcare were you hoping would get more funding in this year's Federal Budget?

newsGP weekly poll What areas of healthcare were you hoping would get more funding in this year's Federal Budget?



Login to comment

Dr Edward Thomas Wu   5/05/2021 1:23:48 PM

Useful insight to keep in mind but important "common sense" balanced view from the real world of primary care/general practice from Prof Zwar.