Primary aldosteronism – a neglected cause of high blood pressure
You might already know it’s important to maintain a normal blood pressure to reduce your risk of having a heart attack or stroke. You might have even had your blood pressure checked recently as part of a Heart Health Check with your GP.
And if you have high blood pressure, chances are your GP has already told you about some of the things you can do to manage it, like stopping smoking, cutting down on alcohol, and reducing your intake of salty foods. But did you know there are some other less common causes of high blood pressure that often go undetected?
A person’s blood pressure is controlled by a whole range of different mechanisms working together, including your heart, nervous system, kidneys, and certain hormones. One of these hormones is called aldosterone.
Aldosterone is produced by the adrenal glands, which sit on top of each kidney. Its main role is to maintain the salt (sodium) and water balance of the body; it helps the body absorb sodium via the kidneys. This in turn ensures the body can maintain normal blood pressure. For example, if your blood pressure is low, aldosterone will make the body hold onto sodium, which in turn causes the body to retain water. This will help your blood pressure increase back up to a normal level.
Primary aldosteronism is a condition where the adrenal glands produce too much aldosterone, even when the body does not need it. This causes the body to hold onto too much sodium and water, which leads to high blood pressure – which leads to high blood pressure. In addition, aldosterone excess causes a higher risk of stroke and heart attack compared to just high blood pressure alone.
Dr Jun Yang is Head of the Endocrine Hypertension Group at the Hudson Institute of Medical Research and a Senior Research Fellow in the School of Clinical Sciences at Monash University. She is a Heart Foundation Alumni who received a 2017 Vanguard Grant for her research project, Finding a curable cause of high blood pressure.
A number of studies from overseas indicated that primary aldosteronism is quite common among patients with hypertension. However, very few doctors actually look for the disease. Without a screening blood test, primary aldosteronism can easily go undetected.”
My research project, partly funded by the Heart Foundation, was the first one in Australia to explore how many patients may be diagnosed with primary aldosteronism if their GPs proactively screened for the disease.” says Dr Yang.
Her research found that primary aldosteronism is much more common than previously thought in clinical practice. A survey of general practitioners, completed at the start of the research project, found that less than 0.1% (1 out of 1000) of people with high blood pressure were diagnosed with primary aldosteronism. After screening new patients with a blood test, a much higher proportion were found to have primary aldosteronism.
Dr Yang and her team found that in a staggering 14% of people with high blood pressure who were screened by their GP, the cause was too much aldosterone.
People aren’t aware, and neither is their GP. This means there are potentially hundreds of thousands of Australians in the community with this condition, which can be diagnosed with a simple blood test,” explains Dr Yang
The good news is there are already treatments available for primary aldosteronism - either with medicine to block aldosterone, or in some cases, surgery to remove the overactive adrenal gland.
These findings are important because they demonstrate how we can identify and treat more people with high blood pressure effectively, and potentially save more lives from the devastating impacts of heart attack and stroke,” says Dr Yang
Dr Yang was also a Chief Investigator on a Heart Foundation 2018 Vanguard Grant investigating the levels of aldosterone in adolescents and young adults.
So far, we have been able to establish a link between blood pressure and aldosterone levels even from an early age. There are also clear differences between the sexes. Down the track, this may help us to understand how we might need to tailor our diagnostic tests and treatment to young women and men,” explains Dr Yang.
Dr Yang is currently working on establishing the prevalence of primary aldosteronism in a larger community-based population and identifying biomarkers to detect the condition as early as possible. She is also evaluating how cardiovascular disease risk is affected by primary aldosteronism, especially in relation to existing cardiovascular disease risk calculators (like the Heart Age Calculator).
Primary aldosteronism appears to be a condition that is flying under our radar. It’s not a new disease and the good news is effective medicines are already available to treat it. Primary aldosteronism is very simple to test for and relatively inexpensive to treat. We just need to put better systems in place to look for it.”
Last updated13 May 2021