ACE Inhibitors During the COVID-19 Pandemic

Using ACE Inhibitors During the COVID-19 Pandemic

Inhibitors of the renin-angiotensin-aldosterone system are commonly used in the clinic (e.g. ACE inhibitors have been shown to be effective against hypertension). SARS-CoV2 also interacts with the renin-angiotensin-aldosterone system via the angiotensin-converting enzyme 2 (ACE2), and this interaction may determine how infectious the virus may be. Because of this physiological interaction, DOI: 10.1056/NEJMsr2005760 that ACE inhibitors should not be used during the COVID-19 pandemic, lest they make patients more susceptible to SARS-CoV2.

However, many people who take ACE inhibitors are also older, which puts them at higher risk for COVID-19 as well. In this problem set, we will explore whether age is a confounder of the association between ACE inhibitor use and COVID-19 susceptibility, using hypothetical data.

Using the following table, calculate (showing your work!) and interpret:

Age group

ACE inhibitor use

Total number of people

Number of COVID-19 cases

60 or older

Yes

4,000

1,500

No

20,000

12,500

<60 years of age

Yes

3,500

850

No

37,250

15,000

A. The cumulative incidence ratio (i.e. risk ratio) associated with ACE inhibitor use in the 60 and older age group. For this and all other calculations, only round during the last step. We will accept any reasonable, mathematically correct rounding.

B. The risk ratio associated with ACE inhibitor use in the <60 age group.

C. The risk ratio associated with ACE inhibitor use in the overall population (for that, you will need to do some extra math!)

2) Based on your answers to 1), does potential confounding by age result in an over- or under-estimate of the true association, assuming no other biases? 

3) Does age meet the definition of a confounder? Why or why not? Be sure to address all three criteria. 

Extra credit: what is this method of adjusting for confounding called? Describe, in detail, two other methods you could use to adjust for age as a potential confounder in this study (either in the design phase or in the analysis phase). 

https://www.nejm.org/doi/10.1056/NEJMsr2005760