Wednesday, June 07, 2006

Evidence Based Medicine

We all pride ourself in praactising evidence based medicine. That is what we have been taught and may also be what separates us from those practising alternative medicine and OTC supplements agencies/direct selling/MLM Pyramid type scams. I have always understood clinical trial results for drugs and devices in the light of my understanding of medicine. All clinical trial results must make medical sense, is what I usually tell students and doctors who ask.

The May 17 2006 issue of the Journal of the American Medical Association, carries an article by Dr Pau Ridker and Dr Joses Torres, both from Harvard, Boston. In an article entitled "Reported outcomes in major CVS clinical trials funded by for-profit and not-for-profit organisiations". they reviewed 324 consecutive superiority CVS trials published in JAMA, NEJM and Lancet between 1st Jan 2000 and 31st July 2005. In 104 trials funded by not-for- profit organisation, they were as likely to be positive as to be negative. Whereas, in those trials funded by for-profit organisiation, they were 67.2% more likely to be positive. In the 62 trials, jointly funded, the chance of being positive is about 56.4%. But in the devices studies, of the 39 studies reviewed, 50% of those who were funded by not-for-profit organisiation tended to be positive when compared to standard therapy, but those who were funded by for-profit organisations, 82.4% were positive, resulting in approval for the device.

It is, therefore, important to remember this fact whenever we look at clinical trial results of drug trials and also devices trials. Basically, there may be some bias in clinical trial especially when they are funded by the pharmas holding the patent. This is not surprising. Organisiations are unlikely to spend millions of dollars only to be negative (although some have, The Value trial - Novartis, and the Prove-it trial-BMS, quickly come to mind).

Remember, clinical trial results are important, but they must follow medical pathogenetic mechanism, and medical sense.

1 comment:

huajern said...

The difference may be due to publishing bias. The 'negative' studies may be downplayed, or not submitted for publication at all.