Factors for decision making

Discussion and limitations of the evidence

The studies included in this evidence review are observational studies, which can be subject to bias and confounding and have many limitations affecting their application to clinical practice. Retrospective observational studies are subject to data being recorded accurately, completely and consistently. This type of study cannot reliably answer the research questions: the results can only be considered hypothesis generating and cannot support any definitive conclusions.

As SARS-CoV-2 (the virus that causes COVID-19) is a novel virus and new data are emerging every day, the search was expanded to include indirect evidence to inform the background. In addition to the 2 studies presented, this summary reviews letters published in peer-reviewed journals on the biological plausibility of the role of ACEIs and ARBs in COVID-19.

The conclusions of these letters were primarily based on data from in-vitro and animal models. Furthermore, the correspondence is conflicting and puts forward arguments for both stopping and using ACEIs and ARBs in COVID-19. Some letters also referenced epidemiological data in which conditions commonly treated with ACEIs or ARBs, (such as hypertension, diabetes and coronary heart disease), were shown to be associated with an increased risk of COVID-19 and more severe COVID-19. Such extrapolation is subject to bias and there are many known confounders associated with ACEI and ARB prescribing, developing COVID-19 and severity of COVID-19 (such as age, diabetes, hypertension, obesity and smoking).


Despite biological plausibility for the role of ACEIs and ARBs in both increasing and decreasing the risk of COVID-19 and its complications, this evidence review has not found any observational or experimental data to support these hypotheses. However, the risks of stopping treatment with an ACEI or an ARB, such as worsening heart failure or hypertension, are well understood.

See the full evidence review for more information.

Commissioned by NHS England

ISBN: 978-1-4731-3764-6