Blog | Monday, December 1, 2014

The absence of evidence is not the same as evidence against

We have a huge dilemma in this era of evidence-based medicine. We expect an evidence review to help us make clinical decisions. But sometimes the evidence does not exist. We always have new clinical situations that we must address, before anyone has accumulated evidence.

Of course the example that I use is the approach to possible Fusobacterium necrophorum pharyngitis. In a paper we published a few years ago we established clearly that some patients with F. necrophorum pharyngitis develop bacteremia. We know that around 80% of Lemierre's syndrome results from that bacterium.

Yet many experts opine that we should withhold antibiotics in adolescents (redefined for this post as around 15 to around 30) with significant pharyngitis. In a paper I published 5 years, I provided the evidence that Lemierre's syndrome occurs more frequently than acute rheumatic fever. Yet the newest pharyngitis guidelines continue to exclude prevention of Lemierre's syndrome from consideration because we have no evidence that treating pharyngitis would prevent this severely morbid and occasionally mortal syndrome.

If we believe the germ theory (to be read with a note of sarcasm), then how could we believe that antibiotic treatment of Fusobacterium pharyngitis would not decrease the possibility of Lemierre's syndrome and also the possibility of a peritonsillar abscess.

What evidence do we need to address this serious infection in adolescents?

Of course I have only given 1 example, but I am certain that our creative readers could suggest more such examples. When we have no evidence then we must use the best logic we can muster. If new evidence arrives then we should modify our thought process, but until then …

db is the nickname for Robert M. Centor, MD, FACP. db stands both for Dr. Bob and da boss. He is an academic general internist at the University of Alabama School of Medicine, and is the Regional Associate Dean for the Huntsville Regional Medical Campus of UASOM. He still makes inpatient rounds over 100 days each year. This post originally appeared at his blog, db's Medical Rants.