EBM: misunderstood and misused

It is ironic that evidence-based medicine was introduced, not to eliminate variability, but to ensure that variability was both present and appropriate.  The intent was to ensure that physicians varied what they did based on the nuances of the evidence and incorporating patient values and preferences. 

The problem was not variability but a lack of variability.  Evidence-based medicine was not an attempt to reduce variability by individual physicians, it was an attempt to INCREASE variability by individual physicians.

This has been misunderstood - and EBM has been misused - because it was geographic variability that was the first clue to inappropriate lack of variability on the part of physicians. Physicians in one community would do a high number of tonsillectomies or hysterectomies, while physicians in a different community would do a much lower number.  There was unexplained variability between the two communities, but this was not the issue. This was a clue to a deeper problem: the individual physicians in these communities were NOT varying their treatment approaches based on either evidence or patient characteristics. They were invariably doing what they were most comfortable with.

The goal was not to eliminate variability, but to replace irrational geographic variability with rational and appropriate individual variability. Instead of taking the tonsils out on every child with strep throat, the approach should be to use the evidence about tonsillectomies, the child's history, and the family's preferences in order to determine one's approach based on these individual VARIABLES.

To use a mundane and more modern example, the goal of evidence-based medicine is not to mandate that all patients with a given LDL be treated with the same dose of the same medication, though this is the way many agencies and institutions have misinterpreted it. The goal is to encourage physicians to find and use the data that applies best to a specific patient in a specific circumstance. Guidelines are not evidence. They are nothing more than opinions of small groups of experts, often self-anointed and sometimes with significant conflicts of interest, and are intended to explain how they would use the evidence. 

Previous lipid guidelines listed numeric thresholds and targets for treatment. In part because of new evidence, but in large degree as an expressed and explicit response to the recognized MISuse of guidelines to support hard targets, the most recent lipid guidelines move strongly in the direction of assessing individual risk and then making individual treatment decisions based on that. Instead of treating everyone with an LDL of 180 with a statin and adjusting the drug and dose to get their LDL under 100, the approach is to use the evidence to assess the patient's 10 year risk of cardiovascular disease, the risks and benefits of treatment versus non-treatment,  and the patient's values and preferences to determine the best course for each unique individual.

Institutions will be slow to adjust their approach and reluctant to give up the old paradigm of evidence-based recipes to drive care and evaluate quality.  It isn’t hard to understand why. For one thing, it means they have to admit that they do not know better than the clinicians. For another, it makes it much harder to define and measure quality. The biggest barrier to adopting a more appropriate (individualized and patient-centric) use of evidence, however, is that there is considerable money on the table for quality, and it is much harder (and less certain) to work on actually improving quality to reach quality targets (and get paid) than it is to continue pretending that eliminating individual clinical variability and enforcing clinically inappropriate behavior is the answer.




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