Blood pressure drugs could protect against type 2 diabetes

Blood pressure drugs could protect against type 2 diabetes
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Using blood pressure drugs is an effective way to reduce a person’s risk of developing type 2 diabetes in the future, according to new research by the British Heart Foundation.

Doctors already prescribe blood pressure drugs to reduce a person’s chance of having a life-threatening heart attack or stroke, but whether these drugs can help to stave-off diabetes have been unknown.

After much uncertainty, this study reveals that their protective effects are wider-reaching than previously assumed and could potentially directly reduce an individual’s risk of type 2 diabetes – a condition that 13.6 million people in the UK are now estimated to be at high risk of developing.

Reducing type 2 diabetes with blood pressure drugs

In the largest trial to date, using over 145,000 people from 19 randomised clinical trials across the world, researchers at the Universities of Oxford and Bristol found that a 5mmHg reduction in systolic blood pressure is achievable using blood pressure drugs or lifestyle changes. However, it reduced the risk of type 2 diabetes by 11%, and after an average of 4.5 years, only 9,883 participants had developed type 2 diabetes.

This risk reduction was confirmed using a genetic data analysis approach called Mendelian randomisation, which uses naturally occurring genetic differences to randomly divide participants into groups, mimicking the effects of running a clinical trial. People with genetically influenced lower blood pressure levels had a 12% lower risk of type 2 diabetes than those without genetic associations.

Professor Kazem Rahimi and his team investigated the effects of five major types of blood pressure drugs from 22 clinical trials compared to a placebo. They found angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor-II blockers (ARBs) had the strongest protective effect, both reducing a person’s relative risk of developing diabetes by 16%.

Further research found other blood pressure drugs were not protective. Calcium channel blockers had no effect on diabetes risk, while beta-blockers and thiazide diuretics increased the risk of diabetes. The opposing effect of different types of drugs on diabetes risk is most likely due to the way they act in the human body, independent of their ability to lower blood pressure.

These results from clinical trials and genetic studies show that lowering blood pressure can prevent type 2 diabetes at a similar scale already known in order to avoid major cardiovascular disease.

Preventing diabetes in high-risk individuals

Keeping a healthy weight and maintaining a healthy lifestyle is currently recommended to reduce the risk of diabetes; however, this may not be sufficient for those at high risk of developing type 2 diabetes. Researchers now claim that existing drugs such as ACE inhibitors and ARBs (blood pressure drugs) should be considered as part of a treatment plan. Further research into other interventions to prevent diabetes will also be a priority.

Professor Kazem Rahimi, lead researcher of the study at the University of Oxford and consultant cardiologist, said: “Current clinical guidelines do not provide clear recommendations on lowering blood pressure as a strategy to prevent type 2 diabetes. Our research provides clear evidence that giving ACE inhibitors or ARBs, which are widely available and affordable worldwide, to patients at high risk could curb the growing burden of type 2 diabetes.”

Blood pressure and diabetes

Professor Sir Nilesh Samani, the British Heart Foundation Medical Director, said: “Diabetes and high blood pressure are two important and growing problems which increase a person’s chance of developing an array of other serious health complications, including heart attacks and strokes. This research shows that the two are inter-connected and that lowering blood pressure could be a powerful way to reduce the risk of developing diabetes.

“It also shows that different commonly used drugs for lowering blood pressure have very different effects on risk of diabetes. Doctors should therefore consider the patient’s risk of developing diabetes when they are choosing an anti-hypertensive drug to lower their blood pressure.”

The research was also funded by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre and the Oxford Martin School.

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