The Curious Impact of Overdiagnosis
There is a very curious aspect to the process of diagnosis. It's called overdiagnosis, but it should be called causing more harm than good. Overdiagnosis is defined as correctly identifying a problem or disease is present, but finding this out provides no benefit to the person, and may cause harm.
This is not misdiagnosis where one is told they have a condition when in fact they do not have that condition. And, it is not the same as overtreatment where excess medication is prescribed or excess procedures are done whether the diagnosis is correct or not. (Coon, et al, Overdiagnosis: How Our Compulsion for Diagnosis May be Harming Our Children, Pediatrics, Nov. 2014, pp. 1013-1023)
The problem of overdiagnosis is mostly discussed when it comes to some very prominent illnesses seen in adults, in particular three common cancers, prostrate, breast, and thyroid; but, is seen in a variety of pediatric conditions, some rare, but some common, as noted in the Pediatrics reference above.
An Example from the Adult World
A lot of adults will develop a lump in their thyroid gland sometime in their life. The advent of imaging has allowed us to detect many more such lumps and so the rate of them being removed has gone up dramatically. Often these lumps will contain a few cells that fit the definition of cancer. Some call these micro-cancers. They almost never spread, and it appears if they were not detect, no harm would happen. But because of the advent of imaging and biopsing, the incidence of thyroid cancer in the US has tripled. In South Korea, every adult is screened with a thyroid ultrasound, so there the incidence of thyroid cancer has gone up 15-fold, and there thyroid cancer is now the #1 most common cancer. But, both in the US and South Korea, the chance of dying from thyroid cancer has not dropped, at all.
Think about that for a moment. In two nations, millions of people have been screened for thyroid cancer, and many, many more people than before have had their thyroid cancer long before it has spread anywhere. And yet, despite early detection, and early intervention, no benefit materialized.
Even worse, the fact that no lives were saved means that those thousands and thousands of people told they had cancer would have been fine not finding out. The incidence of permanent complications from thyroid surgery in South Korea has gone up dramatically.
So, not only was no benefit delivered, but great harm has been done.
This is the essence of overdiagnosis.
A great summary of this example, and of this subject overall is found in the May 11,2015 essay by the great Dr. Atul Gawande, originally from Youngstown, but now a major leader in re-thinking medical care at Harvard Medical School: http://www.newyorker.com/magazine/2015/05/11/overkill-atul-gawande
How Overdiagnosis shows up in Children
The review cited above in Pediatrics lists 11 illnesses that children can experience in which significant overdiagnosis may be happening. The conditions range from gallstones in adolescents (which often are seen on a scan but turn out to be harmless 95% of the time), to jaundice in the newborn period (very, very common, but typically harmless), to hypercholestrolemia (new screening guidelines for 9-11 year olds could commit 200,000 children to drug therapy for no clear proof that it will help them).
A striking example involves the diagnosis of low oxygen levels in babies with bad respiratory infections. Since the invention of oxygen monitoring devices, the chance a baby with a bad cold will get admitted to the hospital and placed on oxygen pending the level returning to normal, has jumped dramatically. But despite all the extra oxygen and hospital care, the chance of a bad outcome with a bad cold in infancy has not changed at all over the last decade or two. Here is a case where getting the diagnosis (in this case, your oxygen level is low) is correct, but not helpful.
A common example includes food allergies. There are three tests for food allergies- a skin test, a blood test, and a what-happens-if-you-eat-it test. The only one that really matters is seeing what happens if you eat the food. It turns out that blood testing finds antibodies in the blood that might lead to allergic reaction, but it turns out that antibodies to a food are found about 7 times more often than actual reactions occur. So a blood test can give you a diagnosis of food allergy, and does in about 17% of children, but a true allergic reaction only occurs in 2.5% of children.
- Diagnosis is all about getting it right.
- But errors lurk in so many directions- one can say you have an illness or condition when you do not, or one can have the illness but still not need any intervention.
- Overdiagnosis is the error of being correct that someone has a problem, but finding that out offers them no benefit, and may cause serious problems from the unnecessary intervention.
- The best protection against overdiagnosis, misdiagnosis, and overtreatment, is accuracy in the diagnostic process. That requires tremendous vigilance to details on how medical care is given, to avoid both overdoing and underdoing a level of investigation.
At Advanced Pediatrics, we are committed to thinking very carefully about how to not only be accurate in making diagnoses, but making sure doing so will actually translate into real benefit.
To your health,
Dr. Arthur Lavin
One more reference is a great book on this subject by H. Gilbert Welch and his team at Dartmouth:
Over-Diagnosed, Making People Sick in the Pursuit of Health (2011, Beacon Press)
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