Boners, Blindness and Evidence Based Medicine

or "Your Erection is purely anecdotal"

Not sure why this article on the possible connection between erectile dysfunction medications and adverse ocular events caught my eye. I think it’s the cock-sureness of the Evidence Based Medicine crowd just kinda chaps my backside. The smug assurance around RCT’s can rub me the wrong way as these folks seem to think that science happens in some kind of purely, first principles process. Nothing could be further from reality.

Science starts with an observation. Then a hypothesis forms around the observation. Then experimentation, informed by the hypothesis. Then (usually) some kind of updating of the model: rinse, lather repeat. Slowly, our ability to accurately describe the world and predict what will happen under various circumstances improves.

Some key points from the article:

These ocular adverse events have previously been reported with use of PDE5Is, but mostly in the form of anecdotal studies that produced inexact estimates for these risks. "Results of this study suggest that individuals who regularly use PDE5Is should be cognizant of ocular adverse events associated with these drugs and alert their physicians if they experience any visual deficits,"

The emphasis above is mine. The funny thing about this is this class of drugs was developed initially to treat angina. The thought was improving nitric oxide release would open coronary arteries, reducing discomfort and perhaps even save some lives. It was an OBSERVATION (also called an anecdote) that men receiving the medication would oftentimes develop an erection.

I can see the Evidence Based Horde brow-beating these poor chaps:

Patient:

“Doc, I’m here for a study looking at heart disease, but I’ve had an erection for 6 hours!”

Doctor:

“Nonsense! That’s purely anecdotal”

Patient:

You may think I’m being silly, but I’m really not. A remarkable number of folks in science and medicine have adopted this oddly non-scientific approach to navigating the world. No, we do not ascribe end-stage scientific weight to anecdote, but it’s also ridiculous to dismiss it out of hand (trying to fit in as many erection related quips as I can…) A reasonable response might be “well, that’s interesting, let’s look more closely at that…”

Anyway, back to the article, this is an important outtake:

"this study also had a weakness that has plagued previous inquiries into the ocular adverse events related to PDE5I use."

Many of the risk factors for the indications for using PDE5Is -- hypertension, diabetes, and coronary artery disease -- are also risk factors for SRD, RVO, and ION, they added, and the prevalence of these risk factors in this study was substantially higher among cases versus controls.

So, the things that would normally leave one needing ED meds (diabetes, obesity, hypertension etc) are also things that would predispose one to adverse ocular events.

And this brings us to the wacky reality that science never really stops and asking one question oftentimes spawns many more. Here are just a few possible scenarios that may describe what’s happening:

-This negative effect occurs only in otherwise unhealthy people.

-This negative effect occurs only in otherwise healthy people.

-There is actually no effect here, it’s an artifact of the type of sampling done and this really is “just anecdotal,” nothing to see here, move along.

-Something else.

Nothing earthshaking with this piece, just a reminder that science starts with OBSERVATION. When folks really grock that the weird internet pettiness and priggishness seems to diminish if not resolve entirely. All that is replaced with something a lot more functional: curiosity.