Thursday, November 3, 2011

Is an Ounce of Prevention Worth a Pound of Cure?

True or false:   
Earlier disease diagnosis leads to more effective treatment and better outcomes.  
Most of us wouldn’t hesitate in responding true and yet maybe we should.  Early diagnosis can carry risks as well as benefits.   During the Bicknell Lectureship in Public Health at the BU School of Public Health, Dr. H.Gilbert Welch, a professor of medicine, practicing clinician and director of the Center for Medicine and Media at the Dartmouth Institute for Health Policy and Clinical Practice, was joined by a panel of health care professionals to discuss whether we need to reevaluate the value of diagnostic screening.
How early is too early?  
Today, Dr. Welch noted, patients are often diagnosed long before they become symptomatic.  Fueled by improvements in test sensitivity and the availability of new therapies, the diagnostic threshold for many diseases has been lowered, increasing the number of people who are classified as needing treatment. The problem with early diagnosis is that there may be a significant number of these “patients” who may not actually develop health problems. For this group significant harm can result from unnecessary treatment.  These patients, according to Dr. Welch, are overdiagnosed.  
The popularity paradox  
Many of us can probably point to a friend or family member whose life has been saved by early diagnosis and intervention. However, survivor stories, focusing only on benefits, can lead to a popularity paradox, making screening appear more valuable according to Dr. Welch.  He pointed out that it’s also important to look at screening value from a global perspective. Epidemiologists have suggested that even if a screening test correctly identifies people with preclinical disease, its effectiveness is measured by its ability to reduce disease related morbidity and mortality. (1) Yet, according to data presented by Dr. Welch, the increased incidence of many diseases, such as thyroid cancer, has been associated with stable death rates. We may be suffering from a diagnosis epidemic not a disease related one. 
In October 2011 the US Preventive Services Task Force (USPSTF) proposed new  recommendations on PSA screening,  advising against its use in healthy men.   Prostate cancer screening is often cited as a prime example of the problems associated with overdiagnosis.  Writing in the New England Journal of Medicine, Richard Ablin, developer of the prostate specific antigen test (PSA), noted that several studies have found prostate screening did not reduce the death rate in men over the long term.  Ablin urged the medical community to rethink the use of PSA screening to “rescue millions of men from unnecessary, debilitating treatments.”  Putting this in perspective, Dr. Welch presented data on prostate cancer that found for every life due to screening, 30 to 100 patients are overdiagnosed.   
It’s about better care, not denying care
Dr. Kenneth Lin, a practicing clinician, Assistant Professor of Clinical Family Medicine at Georgetown University School of Medicine and former medical officer for the USPSTF, echoed Dr. Welch. He emphasized that individual patients and emotional experience cannot be discounted in formulating screening recommendations; however, this must be countered with evidence that people can experience harm from overdiagnosis.  It’s about striking a balance, he said, between science and emotion.  
Dr. Deborah Bowen, Chair of the Department of Community Health Sciences at the Boston University School of Public Health, spoke about genetic screening tests.  She observed that patients may have difficulty understanding what genetic test results, such “at risk”, mean.   She cited numerous studies which have shown that patient misunderstanding can lead to anxiety, decreased quality of life, false assurance and poor choices.   In these cases, she concluded, screening can create more harm than good.  
Dr. John Fallon, Senior Vice President and Chief Physician Executive at Blue Cross Blue Shield of Massachusetts, explained that employers want to be fair in determining what screening tests to cover but they also want to see evidence that screening has value.   Furthermore, he emphasized that we need to have the courage to change course when scientific data suggests clinical practices are not helpful. 
Time to shift priorities?
Dr. Welch and the panelists agreed that more thoughtful consideration of the risks and benefits of screening is essential to providing better care for individual patients.  As Dr. Welch noted, it’s important to tell both sides of the story. He added that we may also need to rethink our health care priorities, focusing more on health promotion versus early diagnosis. Early diagnosis focuses on looking more closely for health problems, while health promotion focuses on good preventive maintenance:  eating healthier foods, exercising regularly, using alcohol in moderation and smoking cessation. 

In other words, "is an ounce of health promotion worth a pound of cure?"
You can read more about overdiagnosis in Dr. Welch's book, Overdiagnosed: Making People Sick in the Pursuit of Health.  Profits from the book are donated to charity. 
(1) Aschengrau, Ann and George R Seage III. Essentials of Epidemiology in Public Health. Sudbury: Jones and Bartlett, 2008.

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