Blog | Tuesday, February 8, 2011

QD: News Every Day--Overdiagnosis and the potential for harming patients


Screening and diagnosing healthy, asymptomatic people with a barrage of tests has created a culture of illness, write three Dartmouth physicians and researchers in the book Overdiagnosed: Making People Sick in the Pursuit of Health.

In one interview with Kaiser Health News, co-author H. Gilbert Welch, MD, MPH, described the outcomes for 2,500 women who receive an annual mammography starting at age 50 for 10 years. One woman among that group will avoid dying from breast cancer. Nearly half will have an abnormal mammogram, causing needless worry. Half again will have a biopsy. Between five and 15 will be overdiagnosed and receive treatments for a non-problematic cancer.

Not all screening is bad, the authors acknowledge. "If a woman feels a new breast lump, she should come in to see her doctor--that’s not screening, that’s diagnosing," Dr. Welch told The Boston Globe.

The value of screening and preventive measures is constantly being examined. In the past year alone, studies large and small have looked at whether colonoscopy prevents colon cancer, whether screening for osteoarthritis prevents fractures (and is it effective for men), whether false positives from CT scans for lung cancer do more harm than good and does starting mammography too early have any value?

The book also questions the value of wellness programs that outline specific clinical values for blood pressure, cholesterol and blood sugar, as well as the wisdom of an annual physical. Dr. Welch hasn't had an annual exam since childhood, adding "The virtue of having a regular primary care physician is to establish a relationship and to establish the set of values that will guide your care."

For more on the need for an annual physical, see ACP Internist's cover story "Rethinking the value of the annual physical" from our January 2010 issue.

Screenings have become a consumer product to the degree that Consumer Reports has published a review on the matter. More than 8,000 people were asked whether they had received any of 10 heart-specific screening tests in the last five years. Nearly two-thirds of them, all between 40 and 60 years old, had seen a doctor in the last 12 months, and had no history or symptoms of any form of cardiovascular disease. Yet, they said they would definitely have a complete battery of heart-screening tests if they were free.

More importantly, many of the respondents already had: 50% had undergone an electrocardiogram; 21%, an exercise stress test; 7%, an ultrasound of the carotid arteries. Most of them did so without talking with a doctor about the accuracy of the tests, potential complications, or what they would need to do with the findings. 87% completely or somewhat agreed that it was "better to have a scare that turns out to be nothing than to not get tested at all."