Wednesday, July 13, 2011

High-Cost Decision Making: More Than Just "Defensive Medicine"

Last month (June 11) I wrote about defensive medicine and how it drives up health care costs.  I also said there was more to the story and promised to return to that subject, so here it is.

As explained in that essay, concern about the risk of becoming a defendant in a medical negligence lawsuit may drive a physician to order or recommend tests or treatments that clinical judgment suggests are not really necessary.  Instead, those interventions are pursued in order to show that the physician was extra diligent, careful, and thorough in evaluating and treating the patient.  In the event of a bad outcome - and those sometimes occur even in the context of excellent care on the part of a physician - a review of the record will show the physician did "everything possible" and should, therefore, not be blamed.

So "defensive medicine" is all about building a case for the defense, in advance, to protect the physician should there be a bad outcome.  But there are other reasons doctors order or recommend tests or treatments that are arguably unnecessary.

The first steps in the evaluation of a patient, taught to every medical student (usually in the second year of medical school) are described as a "History & Physical" or "H&P."  This means interviewing the patient to obtain a detailed account of the problem about which the patient is consulting a doctor (and sometimes, depending on the context, a much more extensive account of the patient's entire medical history, which is what medical students are taught to do). The history is followed by a physical examination.  This, again, is "problem focused" in ordinary circumstances, but medical students are taught a thorough, head-to-toe approach to encompass every body part and organ system.

Once the H&P is done, a doctor formulates something called a differential diagnosis: a list of possible causes of the patient's symptoms (from the history) and signs (findings on physical examination).  This list is usually made in order of probability, with the most likely cause at the top.

Depending on the nature and complexity of the case, a doctor may be highly confident that the cause is the one listed at the top of the differential diagnosis (at the "simple" end of the spectrum) or may have little or no idea which of numerous possibilities explains the clinical picture (at the "complex" end).  In the latter instance, in fact, the list of possibilities may be constructed not in order of probability, in the physician's judgment, but simply in order of how common the diseases are.

In the former situation, the doctor likely will order no testing of any sort but proceed directly to inform the patient of the apparent diagnosis and make recommendations for treatment.  In the latter circumstance, by contrast, there may be a great deal of diagnostic investigation.  Much of the time, of course, the approach is somewhere in between, with a few possibilities vying for the top spot and only one or a very few tests needed to sort them out.

Judicious ordering of tests requires the use of clinical judgment.  Often there is a question of how much to do in the pursuit of diagnostic certainty.  It may be that, after the H&P, the doctor is 90% certain of the diagnosis.  Should testing be done to raise that to 97%?  (Of course, we are doctors, not engineers, and while we sometimes have real numbers from the published scientific literature in what we call "evidence-based medicine," more often such numbers are very rough estimates.)

As I have already said, fear of litigation is a commonly cited motivation in the pursuit of diagnostic certainty.  But it is not the only one.  In their education (medical school) and training (residency programs after medical school leading to specialty certification) doctors are taught that diagnostic error is unacceptable. No one puts it quite that way, and we all know that there is an irreducible error rate in everything we do in life as human beings.  But we are constantly called to account for every error, and that experience is commonly unpleasant and uncomfortable.  The implicit message conveyed, over and over, is that diligence, care, and thoroughness in pursuit of diagnostic certainty are good things. There is typically far less emphasis placed on balancing the risks associated with our interventions with the benefits.  And there is, in my view, far too little emphasis placed on the practice of cost-effective medicine.  Sure, we can improve our diagnostic certainty by ordering more tests, but is that worth the price tag?  Some tests are quite expensive.  Far too often there is no discussion, between doctor and patient, of these considerations when ordering tests: is the additional information worth the risk and the expense?

And that brings me to the third major driver of "unnecessary" ordering of tests and treatments: customer satisfaction.  This is a hot topic in medical circles, especially among those of us who were trained back in the days when no one called patients customers and few of us thought of our profession as a business or trade.  (Yes, running a medical practice has always been a business, but we thought of our profession chiefly as applied science with an overlay of humanistic arts.)

Now, it seems, everyone (especially managers and administrators) is passionately interested in customer satisfaction: how we can measure it, how we can improve it, and how we can market it when our numbers look good.  I could write a whole series of essays on customer satisfaction, but others have already done that, and I'll make my contributions to the profusion of opinion out there in the blogosphere little by little.  For now, I will just say this.  There has been a great deal published on how to improve customer satisfaction in health care.  Some of it is good science, and some of it is rubbish.  But doctors are human beings and tend to approach many things intuitively.  The intuitive approach is very simple.  If your goal is to have a satisfied customer, give him what he wants.  So doctors figure out what the patients want and give it to them.  Patients who want tests they don't really need tend to get them.  Patients who want antibiotics for colds usually walk out of the doctor's office with a prescription.

A recent study provided an excellent illustration.  Patients visiting an emergency department with abdominal pain were asked about their confidence in the physician's evaluation.  If that evaluation consisted of H&P alone, the level of confidence was only 20%.  It increased dramatically as tests were added, reaching 90% if the evaluation included a CAT scan.

This study only confirms what doctors already know intuitively: patients like tests. If you want satisfied customers, order lots of tests.

That is the wrong conclusion.  Doctors, don't order lots of tests.  Patients, don't go to the doctor wanting or expecting lots of tests.  Instead, after the H&P, talk about the differential diagnosis and diagnostic certainty, and give fair consideration to the benefits, risks, and expense associated with testing.  This is more easily said than done, given that doctors are seeing more and more patients in a day that has only so many hours, and thoughtful discussions are time-consuming.  But give it a try.  Although you may sacrifice a little bit of diagnostic certainty, there is quite often little risk in that.  You may avoid tests that have their own inherent risks, and you may save yourself, and the health care system, lots of money.

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