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Lower blood pressure targets in adults over 80 lowers risk of heart disease
Research shows that intensive blood pressure lowering in adults over 80 years old lowers the risk of heart disease but raises the risk of kidney damage
A new analysis of a study known as the SPRINT study has shown that intensive blood pressure lowering in adults over 80 lowers the risk of heart disease, but also reduces kidney function. The authors believe that on balance the effect is positive. This age group has not been studied extensively; this research is an important step in understanding this age group better, and could be helpful for doctors when making treatment decisions with their patients.
How was the study done?
The SPRINT (Systolic Blood Pressure Intervention Trial) study was an important 2016 study which clearly showed that bringing systolic blood pressure (the top number) down to a target of 120mmHg rather than the conventional target of 140mmHg lowers the risk of strokes, heart attacks and heart failure. This new analysis of the original data, published in December 2019, looks at intensive blood pressure lowering in people aged 80 years or older to see if there is a benefit to more intensive treatment in this age group.
In this study, 1167 older adults with raised blood pressure were divided into two groups at random. Some had their systolic blood pressure lowered to a target of 140mmHg and some to a target of 120mmHg. Blood pressure medicines brought their numbers down to 135.3mmHg and 123.9mmHg respectively.
What did the results show?
After approximately three to four years on average, the group with the lower target blood pressure had:
- lower risk of cardiovascular events (including heart attacks and strokes)
- lower risk of death from any cause during the study follow up
- higher rates of acute kidney injury and declines of kidney function of at least 30% (measured with glomerular filtration rate)
- no difference in the rate of falls that cause injury.
While the risk of kidney problems increased with intensive treatment, the authors noted that the problems tended to resolve with time and believe that on balance the intensive treatment had a positive effect on health.
The authors also looked at the cognitive function (brain function) of the participants and found that those with higher cognitive function benefited from the lower treatment target when it comes to heart health and risk of death, but those with lower scores had no benefit. This suggests intensive treatment is not helpful in people with lower cognitive function.
When the authors looked at walking speed – a marker for physical ability – they found this made no difference to the effect of treatment.
Researching blood pressure treatment in older adults
More and more people are living into their 80s and 90s, but ageing is often accompanied by the development of health problems. Blood pressure tends to rise along with stiffening of the arteries, raising the risk of heart disease and stroke, and other illnesses become more common. Decisions about treatment for high blood pressure can be complex because patients tend to have other health problems and are taking other medicines. For these reasons, high blood pressure in older adults is an important area of research.
In the UK, the NICE guidelines for treating high blood pressure suggest a target of 150mmHg in adults over 80, so this study explored a lower treatment target. The average blood pressure of people in this study was relatively low to start with at 142mmHg, just above the usual cut off for diagnosing high blood pressure of 140mmHg, and the results suggest a possible benefit of a lower target.
One area of debate around lowering blood pressure in older adults due to the risk of falls if blood pressure drops too low, so it is encouraging that this study didn’t find a higher risk of injuries due to falls.
Nirmala Markandu, Hypertension Nurse Specialist at Blood Pressure UK says: "Doctors treating older adults with high blood pressure need to consider many different areas of their patients’ health and well-being to decide on the best treatment, including the risk of falls, other health problems and other medicines, and how they all interact. As more people live into their 80s and 90s, we need more research into blood pressure management for older people, and although this study does not give clear cut answers, it’s an important step in the right direction, giving doctors more information to help them make decisions in blood pressure treatment."