DB’s Medical Rants

"The good physician treats the disease; the great physician treats the patient who has the disease" - Sir William Osler

 I have previously criticized blind acceptance of EBM.  One of my good friends and previous colleagues, Roy Poses, recently engaged an interesting counterpoint to an op-ed criticizing EBM - ‘Evidence-based’ Rx miscues and What Influenced Derision of Evidence-Based Medicine as "One-Size-Fits-All?"

In reading their comments, I would note that they are making arguments about different things.  I hope in this rant to reframe the debate.

At the risk of insulting my religious readers, I will compare evidence based medicine with a belief in a religion, and EBM with a strict adherence to arbitrary rules of that religion.  I would argue that we all want to use the best evidence when we make medical decisions.  The true proponents of evidence based medicine recommend that we interpret the data in the context of our patients.  True evidence based medicine factors individual differences and multiple patient factors.

Unfortunately, too many groups have claimed that they are using "EBM" to make decisions.  These groups release prescriptive guidelines because of their interpretation of the evidence.

One need just compare guidelines that different groups make for the same problem.  The two that I would offer for your perusal are discussed previously in this blog - Guidelines not agreeing and When guidelines differ - prostate cancer.  In the  first example, we have 11 disparate guidelines addressing testing and management of pharyngitis.  These guidelines differ dramatically.  Similarly, the more recent discussion focuses on two camps in the prostate cancer screening debate.

Now in both examples, the guideline authors claim to use EBM to develop their recommendations.  How can we have such disparate recommendations?  As I have done many times, I refer the reader to Allan Detsky - Sources of bias for authors of clinical practice guidelines

In summary, the necessary human factor in making judgments based on multiple sources of data can result in biased recommendations. In the last few years, bodies that convene guideline processes have begun to recognize financial conflicts of interest. To improve the validity of their guidelines, they need to recognize all of the other sources of bias as well. In doing so, they will face the challenge of balancing the expertise of those with intimate knowledge, who are more likely to be subject to these forms of bias, with nonexperts who may have less knowledge but fewer of the influences that contribute to bias — no easy task. Although these other influences may be even more difficult to document and quantify than financial ties, they are no less important. Therefore, I recommend that guideline committees (and those who work on the methodologies they use) study the issue. Such action might further improve the rigour and transparency of the guideline process.

Guidelines are susceptible to many biases.  Dr. Detsky describes these biases clearly. 

The real debate should contrast the proper use of evidence with EBM.  The proper use of evidence focuses on the patient as Sir William Osler clearly reminds us.  We do have a problem when experts or insurers recommend disease standards based on evidence without regard to individual patient context.

We must value evidence and do our best to advance our knowledge of best care.  In contrast we should remain skeptical about EBM proclamations.

I hope this rant makes sense.  While Roy correctly points out one bias that may effect Peter Pitts’ commentary, I would argue that Pitts makes an interesting point.  His "straw man" is correct, albeit for a complex reason.

The theory behind evidence-based medicine is simple: If the government were to run clinical trials testing the effectiveness of drugs and medical technologies, and then use the results to determine what to cover, taxpayers would avoid paying for treatments that aren’t effective enough to justify their price tag.

We must be skeptical of all clinical trials.  Rarely should we let one trial totally change our practice.  As scientists we should critique all studies, and look for the sources of bias, obvious and subtle.

As one who values evidence, I can still fear EBM.  I fear it because too many now proclaim that their data or their analysis answers the question.  In my 30 years since finishing my residency, I have seen too many standards in medicine overthrown to become overexcited about any one study or one proclamation.  I provide the following examples of historical EBM:

1. Hormone replacement therapy to prevent coronary artery disease
2. Avoidance of beta blockers in heart failure
3. Avoid anticoagulation after myocardial infarction
4. Antiarrhythmics after myocardial infarction

I challenge the readers to provide more examples.