Who can participate?

• 18 years or older.
• Have high blood pressure (>140/90mmHg) or are taking one or two high blood pressure medications.
• Have low renin (a hormone measured with a simple blood test through your family doctor).
• Able to attend the Endocrine Hypertension clinic at Monash Health for seven visits in a year.
  Clinic location: Department of Endocrinology, on Level 3, Block E, Monash Medical Centre, Clayton.

What are the benefits of participating?

1. Free blood pressure medication.
2. Comprehensive medical examinations and monitoring.
3. May improve blood pressure control, and heart and kidney health with less medication. 
4. The results of this trial will guide doctors in the optimal treatment for your condition (low-renin hypertension).
5. Free parking for longer appointments (first and last trial appointments).

What will the trial involve?

This trial aims to find out whether measuring the hormone renin with a blood test can identify people who will benefit from early treatment with a blood pressure-lowering medication called aldosterone blockers. The team will do this by randomly assigning individuals to either aldosterone blockers or standard blood pressure-lowering medications and following up for 12 months.

Your medical examinations will include blood pressure measurements, blood tests, urine tests, heart ultrasound, an assessment of the health of your blood vessels and a quality-of-life questionnaire. If you are already on blood pressure-lowering medication, this will be stopped before the trial medications are started.  All the medications used in this trial are safe and have been used in large numbers of people for many decades in many countries.  

At the end of the trial, the team will compare individuals who received aldosterone blockers with standard blood pressure-lowering medications to see if there is a difference in blood pressure control, and the amount of medication needed to control the blood pressure and heart and kidney health.

Would like to particpate? Next steps

• Ask your family doctor for a blood test to measure your renin and aldosterone levels.
• If your renin is <10 mU/L, you may be eligible for the trial.  Your doctor can fax a referral to the Endocrine Hypertension Clinic to (03) 9594 3558 or email to endocrinehypertensionclinic@monashhealth.org.
• Further information on the trial for your family doctor is available here.

Background

High blood pressure is a major cause of death worldwide and affects more than 6 million Australians. Many people with high blood pressure do not achieve good blood pressure control, even with medication. Research suggests that this may be due to undiagnosed hormonal causes of hypertension.

Patients who produce too much of a salt-retaining hormone called aldosterone are diagnosed with a condition called primary aldosteronism. Aldosterone is produced in the adrenal glands and too much of this hormone can lead to high blood pressure and heart disease.

The hallmark of primary aldosteronism is high aldosterone and low renin levels in the blood. This affects one in ten people with hypertension and has treatment options of either aldosterone blockers or adrenal surgery that are quite different to standard high blood pressure treatments.

Some patients do not meet the criteria for diagnosis of primary aldosteronism, but still have low renin levels with either normal or borderline-high aldosterone levels in their blood. This is called hypertension with low renin or low-renin hypertension. Research suggests that up to one in four people with high blood pressure may be classified as having low-renin hypertension. At present, doctors do not know what the best treatment for this group of patients is. The results of this trial will help guide doctors on the best treatment for low-renin hypertension.

Lead researchers

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