Evidence-Based Medicine

Robin Hanson and Free Exchange have recently focused attention on this amusing paper satirizing Evidence-Based Medicine - the über-strict drug licensing approach that has been a major factor in the exorbitant cost of bringing new drugs to market.
A couple of snippets from the paper:
Smith GCS, Pell JP. (2003). Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials. BMJ, 327(7429), 1459-1461.


Results We were unable to identify any randomised controlled trials of parachute intervention.

Conclusions As with many interventions intended to prevent ill health, the effectiveness of parachutes has not been subjected to rigorous evaluation by using randomised controlled trials. Advocates of evidence based medicine have criticised the adoption of interventions evaluated by using only observational data. We think that everyone might benefit if the most radical protagonists of evidence based medicine organised and participated in a double blind, randomised, placebo controlled, crossover trial of the parachute.


One of the major weaknesses of observational data is the possibility of bias, including selection bias and reporting bias, which can be obviated largely by using randomised controlled trials. The relevance to parachute use is that individuals jumping from aircraft without the help of a parachute are likely to have a high prevalence of pre-existing psychiatric morbidity. Individuals who use parachutes are likely to have less psychiatric morbidity and may also differ in key demographic factors, such as income and cigarette use. It follows, therefore, that the apparent protective effect of parachutes may be merely an example of the "healthy cohort" effect. Observational studies typically use multivariate analytical approaches, using maximum likelihood based modelling methods to try to adjust estimates of relative risk for these biases. Distasteful as these statistical adjustments are for the cognoscenti of evidence based medicine, no such analyses exist for assessing the presumed effects of the parachute.


Only two options exist. The first is that we accept that, under exceptional circumstances, common sense might be applied when considering the potential risks and benefits of interventions. The second is that we continue our quest for the holy grail of exclusively evidence based interventions and preclude parachute use outside the context of a properly conducted trial. The dependency we have created in our population may make recruitment of the unenlightened masses to such a trial difficult. If so, we feel assured that those who advocate evidence based medicine and criticise use of interventions that lack an evidence base will not hesitate to demonstrate their commitment by volunteering for a double blind, randomised, placebo controlled, crossover trial.
A commenter (CPT4ICD9) explains:
EBM is something that on the surface makes absolute sense. Of course we want to see that the device or drug we are using has passed the highest level of scrutiny by the experts and authorities. The reality is that it is simply not ethical or practical to create or operate the trials necessary to meet the EBM requirements of the insurance companies and government. It is also prohibitively expensive to do for virtually every startup technology company and the reason why it now costs $1billion to develop a new drug. Just as we have computer simulation developing most of our movies these days, we need the industry to focus on the development of computer simulations and models that will allow the scientists and physicians to accurately assess the impact of the new technologies and drugs on humans WITHOUT having to wait ten years or longer to have the results prove out what we empirically already knew would happen. The challenge is to do so without missing a hidden element as was done with NSAIDS and many other devices and drugs beginning with DES. It took two complete generations before the problems inherent in DES were discovered. New drugs and technologies should not be denied to patients in need while we wait 20 years to see if anyone dies from them. The scientific community needs to develop models to assess their impact on patients with varying degrees of illness and injury. The healthcare system needs to eliminate the liability involved as long as someone signs a waiver when taking a drug or using a device. The insurance companies need to compensate physicians and facilities using the drugs or devices in a fair and consistent manner even if the evidence is being developed. Without such changes we will see a tremendous decline in medical advances outside of the university setting.

No comments: