By Dr. Claire Steves

We have seen reports emerging from China and other countries showing that people with high blood pressure (hypertension), type 2 diabetes or heart disease are more at risk from COVID-19. It has also been suggested that commonly-prescribed drugs for these conditions, known as ACE inhibitors and ARBs, might increase the chances of coronavirus infection.

Nearly 7 million people in the UK were prescribed ACE inhibitors (angiotensin converting enzyme inhibitors) or ARBs (angiotensin receptor blockers) in 2019. 

Are all these people at increased risk of catching COVID-19, becoming seriously ill or even dying from the disease? And what should people do if they are already taking these drugs?‍

The first thing to know is this: large-scale clinical trials have proved that ACE inhibitors and ARBs save lives. Never stop taking any prescribed medication without talking it through with your doctor first.

People who are prescribed ACE inhibitors or ARBs for hypertension, diabetes or heart disease are also at increased risk of becoming seriously ill or dying from these conditions if they stop taking their medication. So there is a balance of risks to be struck.

Thanks to the millions of users of the COVID Symptom Tracker app across the UK, our research team at King’s College London and ZOE have been able to look in more detail at the links between these drugs and COVID-19 to see what might be going on. 

We’ve submitted our findings to a scientific journal and they’re currently being peer-reviewed. There’s a pre-print version of the paper available online here.

What’s the connection between COVID-19 and ACE inhibitors or ARBs?

Scientists have become interested in the connection between coronavirus and these drugs because they might trigger an increase in the levels of a molecule called ACE2. 

ACE2 is a kind of molecular ‘portal’ that sits on the surface of cells lining the lungs and other organs and acts as the gateway through which SARS-CoV-2 (the virus responsible for COVID-19) gets in.

So it makes sense that increasing the number of ACE2 gateways might make it easier for more coronaviruses to get inside cells and set up a serious infection. But we don’t have enough data from large-scale studies to know whether this is really true.

To make things even more confusing, a small number of animal studies have suggested that ACE inhibitors or ARB may even have a protective effect by reducing lung damage in severe cases of COVID-19. Although this hasn’t yet been proven in humans, there are a few small clinical trials currently underway.

Is there an increased risk of COVID-19 with blood pressure medication?

To find out whether there is a link between ACE inhibitors or ARBs and COVID-19, our team looked at data from more than 2.2 million people across the UK who have been using the COVID Symptom Tracker app to report on their health. 

As well as checking in every day to say whether they are feeling physically normal or have any new symptoms, we also ask participants a few questions about their general health and medications.

The app asks three questions about blood pressure medications:

• "Do you take blood pressure medications the name of which ends in ‘-pril’?" (these are ACE inhibitors)
• "Do you take blood pressure medications the name of which ends in ‘-artan’?" (these are ARBs) 
• “Do you take any blood pressure medications?” (this is for people who take other types of blood pressure drugs)
  

We also know from the app whether people are likely to have COVID-19 based on either a positive test, self-reporting classic symptoms such as a fever or persistent cough, or having a cluster of several less common symptoms that indicate they are highly likely to be infected (something we’ve also figured out from the app data). 

After adjusting for other known coronavirus risk factors like age, BMI and sex, we were able to see whether people taking ACE inhibitors or ARBs were more likely to have symptoms of COVID-19 than those who were on different types of drugs or weren’t taking any blood pressure medication at all.

In our dataset, we found that people taking ACE inhibitors and ARBs were twice as likely to report having symptoms of COVID-19 than those who weren’t taking any blood pressure medications, while those taking other types of drug for blood pressure were actually half as likely to show any symptoms.

But - and it’s a big but - we didn’t see the same relationship when it came to people who had actually had a test for COVID-19. In this case, people taking blood pressure medications were just as likely to have a positive test results than those who weren’t. 

This may be because there is relatively limited coronavirus testing in the UK, with tests mostly reserved for people who are directly and frequently exposed to the virus, such as healthcare workers, and seriously ill patients who have been hospitalised. So we can’t be sure what’s going on in the wider population for people who have less intense exposure or less serious disease.

What’s going on?

Frustratingly, these results don’t provide a clear answer at the moment. 

We urgently need to do more research to understand whether blood pressure drugs like ACE inhibitors or ARBs increase the chances of catching coronavirus or becoming seriously ill. This also needs to be balanced against the life-saving protective health benefits these drugs bring for people with high blood pressure, type 2 diabetes or heart disease.

We also need to confirm whether other types of blood pressure drugs have a protective effect against COVID-19, as it may be beneficial for patients to switch as long as there is no increased risk to their health by changing their medication. 

These findings are just one more piece of the big puzzle that researchers all over the world are putting together as we race to understand this deadly new disease. 

We are working as hard as we can to analyse the data from all the millions of reports coming in from our app users every day, so we can generate the evidence that we need to make the best decisions for everyone’s health.