Oh... this would make life simpler, so I hope it works.
Dexamethasone has a duration of action up to 72 hours.
Therefore several researchers have considered it as a potential agent to
streamline the treatment of asthma.
This was a triple blind “non-inferiority” trial looked at
single dose of dexamethasone 12mg
vs. the usual five days of prednisone
(prednisolone can be considered the same).
Included patients were adults with mild to moderate asthma discharged home from
the ED.
The primary outcome measure was relapse as defined by an unscheduled return to a health care
provider within 14 days. (Ok... this
outcome measure is not perfect but probably represented a pragmatic compromise
in the design of the study.)
It was powered to an 8% difference between groups.
Why 8%?
Yes, it’s fairly arbitrary.
And they provided some nebulous justification.
Results?
They kind-of, sort-of, almost met inferiority. There was a
2.3% (95% CI -4.1% to 8.6%) absolute difference in the primary outcome of relapse at 14 days, but the
confidence interval just barely crossed their pre-specified arbitrary margin of
non-inferiority.
So this officially is a negative study. But I don’t really
think so. Nor do the study investigators.
I’ll bet the authors are kicking themselves for not ensuring
the proper statistical power in order to narrow down their confidence interval.
Statistically speaking, the probability of the truth is always closer to the
point estimate.
I also bet the authors are disappointed they didn’t pick a non-inferiority margin higher than 8%!
Either way, I think this is more evidence to suggest that a
single dose of dexamethasone is probably
just as good as the usual course of prednisone. As we get more evidence, we
will surely get a better idea of the true efficacy.
For now, stock up on the dex!
Covering:
Rehrer MW, Liu B, Rodriguez M, et al. A Randomized
Controlled Noninferiority Trial of Single Dose of Oral Dexamethasone Versus 5
Days of Oral Prednisone in Acute Adult Asthma. Ann Emerg Med. 2016;67:593-601.
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