Originally posted by loam
From my perspective, when there is substantial evidence that something is likely, it is still not proven. There is a material difference between
making a despositive determination about something and a probable one. Moreover, I'm surprised a physician would be so willing to speak in terms of
absolutes. (Perhaps, I shouldn't be. But we can save that discussion for another thread.)
As I said, proving something has an effect doesn't make it immune from other studies.
For example, aspirin has fantastic anti-inflammatory and anti-coagulant properties. We know this for a fact, is is proven
. After the drug came
into common use as an everyday anticoagulant, studies found that it can also contribute to stomach ulcers.
So, does proving aspirin has a negative effect take anything away from the proven positive effect? Absolutely not, it's simply two proven facts about
a single entity.
That being said, there are statistical values (namely, power, significance, number-needed-to-treat and number-needed-to-harm) that allow us to look a
a given study about a drug and decide if the study represents proof or suggestion that drug X has effect Y. Just because a study comes out of some
powerhouse university about a drug having some new effect doesn't mean it's proven. All of us, as physicians (as well as the governing boards of
each field) will look at that study, and any performed in the past, and evaluate it on those statistical ground to determine just how strong of a
study it is.
There's a LOT more to proving a drug's effect than you're giving credit for. We don't just run quick, 10-15 patient clinical trials and then start
using a drug for a new treatment.
Medicine is filled with imperfect or erroneous understandings about disease and body function.
Imperfect, certainly. Erroneous, I don't think that's true. There are plenty of disease processes and pathologies that are still poorly understood,
but we don't put bad science in as a placeholder for that knowledge. I am more than willing to admit that I just don't know how the beta protein in
Alzheimer's originates. Is it partially genetic or totally genetic? Is there an environmental factor or not? We just don't know, and I would never
tell a patient (nor would the vast majority of physicians) that Alzheimer's is **definitely** caused through X or Y route.
. Moreover, these "facts" are often riddled with assumptions of benefit that later prove untrue.
I think you need to qualify your use of "often" with examples. If it happens as often as you say, you should be able to find plenty of example in
the last 5 years of medical literature.
For example, NSAIDs do not decrease all types of inflammation, such as in the case of Alzheimer's, which also involves inflammation. Until
recently, NSAIDs were also believed to be beneficial to those with cardio vascular disease on the same 'reduces inflammation' theory, but in fact
turns out to increase the risk of heart attack- particularly for those patients with previous history of heart attack or pre-existing cardio vascular
You're cherry picking. Taking two VERY specific subgroups (cardio patients, but only those with prior heart attack) and then claiming that NSAIDs are
NEVER good for cardio health is being disingenuous. The use of NSAIDs as a daily anti-coagulant/anti-inflammatory is HIGHLY associated with decreased
risk of cardiac event.
Although statin use is associated with decreased mortality after pneumonia, this effect weakens in important subgroups. Only a randomized
controlled study can fully explore the link between statins and pneumonia mortality.
Again, you've picked ONE subgroup out of the larger patient population. Not every therapy will work for ALL patients, but in the general patient
population, statins ARE associated with decreased mortality from pneumonia. If you honestly expect me to put a blackbox warning about the tiny
segments of populations who shouldn't use a given therapy in a conspiracy theory board post, you're nuts.