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Shop Talk: Dexamethasone for COVID-19

July 16, 2020 • Health Care News • Sheila Schindler-Ivens

Shop Talk is a newsletter published by The Evidence Workshop, LLC.  
It helps clinicians integrate the best, available research evidence into front-line practice. 


It’s high time for some good news, which is why we’re reporting on a recent finding suggesting that dexamethasone reduces death in people with COVID-19. Our goal is to leverage this upbeat story to lure you into appreciating the concept of number needed to treat (NNT).

Dexamethasone for COVID-19

On June 16, 2020 researchers from University of Oxford issued a press release indicating that dexamethasone reduces death in patients with COVID-19. The study has not been published in a scientific journal. But a committee overseeing the randomized controlled trial determined that enrollment was sufficient to establish benefit. Investigators indicated that dexamethasone should become a standard of care for patients with COVID-19. Conclusions were drawn in part from NNT.

What’s NNT? 

NNT is the number of people you must treat to prevent 1 bad outcome.

A bad outcome is anything we would rather not have happen, e.g. an illness, injury, fall, or flair-up.

In the Oxford dexamethasone study, the bad outcome was death due to COVID-19.

The question researchers posed was, “How many patients must be treated with dexamethasone to prevent 1 death due to COVID-19?” The answer was 8 for patients who were ventilated and 25 for patients requiring oxygen.

What does NNT mean? 

These values mean that if you use dexamethasone to treat 8 ventilated patients with COVID-19, you will prevent 1 death. You can also prevent 1 death if you use dexamethasone to treat 25 COVID-19 patients receiving oxygen.

Of interest, dexamethasone did not reduce deaths in individuals not receiving respiratory intervention. Thankfully, this group had a lower baseline risk of death than the other two groups. Without dexamethasone, the 28-day mortality from COVID-19 was 41% for patients who needed ventilation, 25% for those needing oxygen, and 13% for those who required neither ventilation nor oxygen.

How can I learn more? 

You can read the full press release at

For information about NNT (including calculations), visit to the Oxford Center for Evidence Based Medicine at

Sheila Schindler-Ivens

Dr. Sheila Schindler-Ivens is a licensed physical therapist who earned her PhD in Rehabilitation Science from the University of Iowa and completed a postdoctoral fellowship at the Feinberg School of Medicine at Northwestern University. Dr. Schindler-Ivens joined the faculty in the Dept. of Physical Therapy at Marquette University in 2005. She directs an independent research...

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