Getting the Diagnosis Wrong

by Danielle Ofri
New York Times

Last week a middle-aged woman came to my office because she had abdominal pain. This is a daily occurrence for doctors who work in general medicine, emergency departments or urgent care centers. There are days when the presence of abdominal pain seems as ubiquitous as the presence of oxygen, and this ubiquity can sometimes dull the sense of urgency. But every doctor knows that the list of possible causes of abdominal pain — what’s called the differential diagnosis — is as extensive as it is varied. It includes the common (acid reflux) and the rare (porphyria), and the benign (constipation) as well as the life-threatening (a tear in the aorta or intestine).

As I talked with my patient and examined her abdomen, my mind ran through this list, prioritizing what diagnoses seemed more likely while trying to keep in mind the more serious conditions that I couldn’t afford to miss. But the question remained in my head: Would I get the diagnosis correct?

Diagnostic accuracy is fiendishly difficult to measure precisely, but it is estimated that doctors get it wrong in one out of 10 to one out of 20 cases. Up until now, the focus of the patient safety movement has been on errors of medical treatment — incorrect medications or dosages, postoperative complications, hospital-acquired infections. But diagnostic errors — incorrect or delayed diagnoses — may be more common and potentially more deadly. The Institute of Medicine has taken up the subject, and its new report offers the chilling observation that nearly everyone will experience at least one diagnostic error in their lifetimes.

Refreshingly, the report did not simply point the finger at the incompetence of individual physicians, as both lawsuits and popular news media tend to do. Rather, it described a Borgesian health care system that seemed designed to stymie the diagnostic thought process. It noted that our reimbursement system favors procedures over discussing and thinking about a case. That is, more money would be paid out if I ordered a magnetic resonance imaging exam for my patient with abdominal pain than if I spent extra time talking with her and sorting out the details.

If I called a colleague to get extra input on the case, or spent time with the nurse who knows the patient, or called a radiologist to discuss whether I actually needed that M.R.I. or could get by with a less expensive ultrasound — none of that would be reimbursed in our current system. Nor would additional phone calls or emails with patients and families, who are arguably the true experts on the case.

Talking about reimbursement may reinforce the stereotype that doctors only care about money. But in reality, if something is not reimbursed, it is hard to get done because there are only so many hours in the day. As a time-pressed clinician, it would be faster, easier and more lucrative for me to simply order the M.R.I. than to actually think about my patient’s case.

So bravo to the Institute of Medicine for recognizing that diagnosis is often a team sport, and that time spent analyzing a case is as critically important as tests and procedures. They have thrown down the gauntlet by explicitly pressing insurance companies to reimburse for the cognitive side of medicine and to eliminate the financial distortion that overwhelmingly favors procedures.

OLYMPUS DIGITAL CAMERAThere are sometimes situations in which getting the exact right answer is not necessary. Just corralling the differential diagnosis into categories of serious versus non-serious is often sufficient. For some patients with abdominal pain, for example, a specific diagnosis may not be needed. If we are able to separate those patients who have serious, urgent conditions, we can often simply observe the others and hold off on expensive tests. For those patients without concerning symptoms, it can often be reasonable to proceed with a treatment even without a specific diagnosis. An acid-blocker, for example, can treat both acid reflux and gastritis, so it may not be necessary to do the tests to distinguish between them. And, of course, many patients will get better with just the tincture of time.

However, it is important to follow up with the patient to see if you were right. One thing that the report pointed out is that many doctors never know of their diagnostic errors because they never learn the outcome of the case. Patients often go to different places for their continuing care, so doctors never learn what happened. A system that allows for feedback so that mistakes can be identified is critical.

Additionally, there needs to be a mechanism for doctors to report the errors they do know about without fear of getting sued or reprimanded. Near misses — errors that almost happen, or errors that do not result in bad outcomes — represent perhaps the largest trove of information for improving health care. Yet medical professionals tend to keep quiet about them, both from liability fears and also from the personal shame that accompanies such errors.

Diagnostic error is much more difficult to tackle than medication errors or procedural errors. The sheer number of possible diagnoses multiplied by infinite human variability makes it much less amenable to the checklist approach that works so well with procedures. Nevertheless, as the Institute of Medicine report has pointed out, there are concrete steps that can make the medical environment more conducive to diagnostic accuracy. We should not hesitate to begin implementing them.

The adage that 90 percent of diagnoses are made just by taking a patient’s history probably is not 100 percent accurate, but it is pretty close. Focusing on increased communications with the patient and between medical professionals easily offers the most bang for the buck in terms of preventing diagnostic errors. The other adage worth remembering is that the most important part of the stethoscope is the part between the earpieces. So before I ordered an M.R.I. for my patient, I asked her to tell me the entire story again. I needed to get a certain part of my stethoscope in gear.  (from the New York Times)