Wednesday 22 March 2017

An RCT of Single Dose Dexamethasone vs. 5 days of Prednisone for Acute Adult Asthma... making life simple

Many emergency doctors have traditionally given a 5 day course of prednisone (prednisolone) for acute asthma. However, can the long duration of action (up to 72 hours) of dexamethasone replace a course of prednisone in a single dose? Certainly this would lead to less prescriptions and greater compliance.

The authors from Oakland, California enrolled 376 patients in a single ED with mild to moderate asthma. This was essentially defined as well enough to go home. They were randomized to either a single dose of dexamethasone 12mg or five days of prednisone 60m.

The primary outcome was “relapse” defined as an unscheduled return visit to a health care provider for asthma within 14 days. This was determined by telephone interview.

It was powered to a non-inferiority margin of 8%. In other words, if the results of the two treatment arms were within 8% then they were considered to be equivalent.  Why 8% you ask...? Ok, it’s a bit arbitrary.


So close...

Relapse rate for dex was 12% and pred was 10%. The absolute difference 2.3%. BUT the 95% confidence interval just scraped above 8%. Therefore this was a statistical fail.

But hold your horses.

There is one important point to emphasize... The study investigators gave the patients the prednisone tablets (or placebo) to take home from the ED. This nullified the prescription filling issue and certainly increased compliance. This biased the study to the prednisone arm.

I think the results are compelling and provide us with ongoing evidence that a single dose of dexamethasone is probably sufficient to treat mild to moderate asthma. This is on the back of numerous similar studies in the pediatric literature. Consistency is a powerful message.

For me, dexamethasone is close enough.