A hypothesis published in a medical journal has raised speculation blood pressure and heart medication could make Covid-19 worse.

Don’t stop taking your meds, is the advice from experts following a letter published in The Lancet medical journal suggesting some medications might make you sicker if you get Covid-19.

Since the letter was published, speculation has been rife on social media, driving several organisations to make statements pointing out there is no evidence to back the hypothesis and that stopping medication could pose a danger.

The medications known as ACE inhibitors (angiotensin-converting-enzyme inhibitors) and ARBs (angiotensin receptor blockers) are often prescribed for people with heart conditions such as hypertension or diabetes.

The letter gives a hypothesis that the way these medications work could be linked to why people with these conditions end up in intensive care. It also lists ibuprofen as being of possible concern.

A hypothesis is not a study and there is no current evidence to back this one up. 

The hypothesis was based on three studies that listed underlying conditions of Covid-19 patients – which did not look at medication the patients were taking. It was formed because the three most common underlying conditions in the studies the letter authors looked at are often treated with ACE inhibitors.

Experts have been quick to point to the lack of evidence. University of Sheffield professor of cardiovascular medicine Tim Chico said:

“This letter does not report the results of a study; it simply raises a possible question about whether a type of blood pressure and heart disease medication called ACE inhibitors might increase the chances of severe Covid-19 infections. It does not give any evidence that confirms this, simply that it suggests such a relationship should be looked for.”

ACE inhibitors, ARBs and ACE2

The hypothesised relationship between the medication and Covid-19 is a bit complicated and acronyms abound. 

In simplified terms, this group of medication relaxes blood vessels and decreases blood volume. This helps lower high blood pressure. 

There’s a side effect though, people taking them tend to have a higher ACE2 (Angiotensin converting enzyme 2) expression. For people taking ARBs this can be two-fold to five-fold higher than in people not taking the medication.

This is what has some scientists worried. SARS and Covid-19 bind to ACE2. Taking medication that increases the amount of ACE2 in your system might be like smearing your front door with honey when ants are around.

The fear is that if there’s more ACE2, then you’re more susceptible to the Covid-19 and more likely to have a severe infection.

The Lancet letter says: “Consequently, the increased expression of ACE2 would facilitate infection with Covid-19. We therefore hypothesise that diabetes and hypertension treatment with ACE2-stimulating drugs increases the risk of developing severe and fatal Covid-19.”

A similar hypothesis was reached by another scientist. Australian-based Professor Murray Esler said he thought it odd Covid-19 was infecting people with hypertension. In the Journal of Hypertension he writes:

“We understand that hypertension increases the severity of Covid-19 illness. This is surprising, on two counts. First, ACE2 expression typically is reduced in hypertension models, and second, hypertension does not appear to impact other infections. One of us (M.E.), a cardiologist with more than four decades of hypertension tertiary care experience, cannot recall one of his patients ever dying from an infection. Infection predisposition in diabetes is evident, but not in hypertension.”

He hypothesises ARBs could “perhaps be harmful” in the Covid-19 pandemic.

Esler declined to be interviewed for this story but said data out of Italy would soon be available.

“What is needed now is the testing of hypotheses.”

Keep taking your medicine

The advice not to do anything drastic when it comes to heart medication has come swiftly and from several quarters. 

Professor Chico’s advice is clear: stopping medication while health services might be stretched is not a good idea.

“I strongly advise anyone on heart medications not to stop or change these without discussion with their doctor.

“If a patient stops their medication and worsens to the point of requiring admission to hospital at the same time as we are dealing with an increase in Covid-19 cases, that would pose the patient a considerable risk and put further strain on the healthcare services.”

Imperial College London Dr Dipender Gill echoes the sentiment.

“Evidence is currently lacking … Furthermore, the acute implications of stopping such medications in relation to effects on risk or severity of Covid-19 infection are not known.”

The British Cardiovascular Society (BCS) together with the British Society for Heart Failure (BSH) also issued a statement: “There is no evidence to support this assertion and that both organisations share the view of the European Society of Hypertension and the Renal Association that patients should continue treatment with ACEi and ARB unless specifically advised to stop by their medical team.”

The European Society of Cardiology has a similar stance.

“This speculation about the safety of ACE-i or ARB treatment in relation to Covid-19 does not have a sound scientific basis or evidence to support it. Indeed, there is evidence from studies in animals suggesting that these medications might be rather protective against serious lung complications in patients with Covid-19 infection, but to date there is no data in humans.”

In New Zealand the following medications are commonly-used ARBs and ACE inhibitors: Candesartan, Losartan, Irbesartan. Captopril (Capoten), Cilazapril (Zapril, Apo-Cilazapri), Eenalapril (Enalapril Ethics, Renitec M), Lisinopril, Perindopril and Quinapril (Arrow-Quinapril, Accupril).

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