Converting ratios to percentage change

How does this all play out in Medicine?

Video published on 9 June 2016 by H. Gilbert Welch.

Listen to Dr. H. Gilbert Welch‘s explanations for converting common medical ratios (relative risks, relative rates, hazard ratios) into percentage change (30% lower, 50% higher).

Related information

Absolute v. Relative Change : Two Different Ways of Saying the Same Thing

Relative measures tend to exaggerate effects (perception of risk, benefit)

Video published on 12 Sep 2015 by H. Gilbert Welch.

Dr. H. Gilbert Welch explains why the general public has exaggerated perceptions of the health risks they face – as well as exaggerated expectations of the benefit of medical care.

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Breast-Cancer Tumor Size, Overdiagnosis, and Mammography Screening Effectiveness

NEJM Screening Mammograms, Analysis by Dr. H. Gilbert Welch

Dr. H. Gilbert Welch gives us a brief explanation of the findings of the New England Journal of Medicine article “Breast Cancer Tumor Size, Overdiagnosis, and Mammography Screening Effectiveness“, October 13, 2016.

Study Abstract

BACKGROUND
The goal of screening mammography is to detect small malignant tumors before they grow large enough to cause symptoms. Effective screening should therefore lead to the detection of a greater number of small tumors, followed by fewer large tumors over time.

METHODS
We used data from the Surveillance, Epidemiology, and End Results (SEER) program, 1975 through 2012, to calculate the tumor-size distribution and size-specific incidence of breast cancer among women 40 years of age or older. We then calculated the size-specific cancer case fatality rate for two time periods: a baseline period before the implementation of widespread screening mammography (1975 through 1979) and a period encompassing the most recent years for which 10 years of follow-up data were available (2000 through 2002).

RESULTS
After the advent of screening mammography, the proportion of detected breast tumors that were small (invasive tumors measuring

CONCLUSIONS
Although the rate of detection of large tumors fell after the introduction of screening mammography, the more favorable size distribution was primarily the result of the additional detection of small tumors. Women were more likely to have breast cancer that was overdiagnosed than to have earlier detection of a tumor that was destined to become large. The reduction in breast cancer mortality after the implementation of screening mammography was predominantly the result of improved systemic therapy.

Less Medicine, More Health

7 Assumptions that drive Too Much Medical Care

Less-Medicine book cover image
Less Medicine, More Health pushes against established wisdom and suggests that medical care can be too aggressive.

The author of the highly acclaimed Overdiagnosed describes seven widespread assumptions that encourage excessive, often ineffective, and sometimes harmful medical care.

You might think the biggest problem in medical care is that it costs too much. Or that health insurance is too expensive, too uneven, too complicated—and gives you too many forms to fill out. But the central problem is that too much medical care has too little value.

Dr. H. Gilbert Welch is worried about too much medical care. It’s not to deny that some people get too little medical care, rather that the conventional concern about “too little” needs to be balanced with a concern about “too much”: too many people being made to worry about diseases they don’t have—and are at only average risk to get; too many people being tested and exposed to the harmful effects of the testing process; too many people being subjected to treatments they don’t need—or can’t benefit from.

The American public has been sold the idea that seeking medical care is one of the most important steps to maintain wellness. Surprisingly, medical care is not, in fact, well correlated with good health. So more medicine does not equal more health; in reality the opposite may be true.

The general public harbors assumptions about medical care that encourage overuse, assumptions like it’s always better to fix the problem, sooner (or newer) is always better, or it never hurts to get more information. Less Medicine, More Health pushes against established wisdom and suggests that medical care can be too aggressive. Drawing on his twenty-five years of medical practice and research, Dr. Welch notes that while economics and lawyers contribute to the excesses of American medicine, the problem is essentially created when the general public clings to these powerful assumptions about the value of tests and treatments—a number of which are just plain wrong.

By telling fascinating (and occasionally amusing) stories backed by reliable data, Dr. Welch challenges patients and the health-care establishment to rethink some very fundamental practices. His provocative prescriptions hold the potential to save money and, more important, improve health outcomes for us all.

More information

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Seven widely held assumptions about the value of medical care

Less Medicine, More Health from Dr. Gilbert Welch

Dr. H. Gilbert Welch is an academic physician, a professor at Dartmouth Medical School, and a nationally recognized expert on the effects of medical testing. He sees the value of medical care, particularly in those who are acutely ill or injured. But in many other settings, we have exaggerated the benefits of medical care and understated its harms. In this video, Dr. Welch examines seven widely held assumptions about the value of medical care.

Assumptions covered
  1. All risks can be lowered
  2. It’s always better to fix the problem
  3. Sooner detection is always better
  4. It never hurts to get more information
  5. Action is always better than inaction
  6. Newer is always better
  7. It’s all about avoiding death
More information
  • Video published on 16 Mar 2015 by Beacon Press.
  • 7 Assumptions That Drive Too Much Medical Care, beacon.
  • Watch more research videos on @DES_Journal YT channel.

Overdiagnosis triggers overtreatment, and all of our treatments carry some harm

Overdiagnosis: Bad for You, Good for Business

Boston-University in the snow image
The decision about whether or not to look for something to be wrong is not a “no-brainer.” Early detection has two sides: while it may help you, it may also hurt you.

Likelihood that a woman with screen-detected breast cancer has had her “life saved” by that screening

2011 Study Abstract

BACKGROUND:
Perhaps the most persuasive messages promoting screening mammography come from women who argue that the test “saved my life.” Because other possibilities exist, we sought to determine how often lives were actually saved by mammography screening.

METHODS:
We created a simple method to estimate the probability that a woman with screen-detected breast cancer has had her life saved because of screening. We used DevCan, the National Cancer Institute’s software for analyzing Surveillance Epidemiology and End Results (SEER) data, to estimate the 10-year risk of diagnosis and the 20-year risk of death–a time horizon long enough to capture the downstream benefits of screening. Using a range of estimates on the ability of screening mammography to reduce breast cancer mortality (relative risk reduction [RRR], 5%-25%), we estimated the risk of dying from breast cancer in the presence and absence of mammography in women of various ages (ages 40, 50, 60, and 70 years).

RESULTS:
We found that for a 50-year-old woman, the estimated risk of having a screen-detected breast cancer in the next 10 years is 1910 per 100,000. Her observed 20-year risk of breast cancer death is 990 per 100,000. Assuming that mammography has already reduced this risk by 20%, the risk of death in the absence of screening would be 1240 per 100,000, which suggests that the mortality benefit accrued to 250 per 100,000. Thus, the probability that a woman with screen-detected breast cancer avoids a breast cancer death because of mammography is 13% (250/1910). This number falls to 3% if screening mammography reduces breast cancer mortality by 5%. Similar analyses of women of different ages all yield probability estimates below 25%.

CONCLUSIONS:
Most women with screen-detected breast cancer have not had their life saved by screening. They are instead either diagnosed early (with no effect on their mortality) or overdiagnosed.

  • What is overdiagnosis?
  • What’s the problem with wanting to know if there’s a cancer or disease lurking in our bodies?
  • What’s the harm?
  • Can you give an example of testing that leads to overdiagnosis and overtreatment?
  • You’ve talked about health conditions defined by numbers, or benchmarks—like high blood pressure, high cholesterol, diabetes, and osteoporosis—numbers that distinguish between who’s healthy and who’s sick. Aren’t those numbers based on sound science?
  • Who benefits from overdiagnosis?
  • Why has there been so much emphasis on screening? Do you think it’s been driven by what the public wants—early warnings—or what the medical profession has imposed?
  • Would you advise patients who are offered testing for various conditions, based on family history or other indicators, to refuse the tests?

Read Overdiagnosis: Bad for You, Good for Business, BU Today, 10.26.2011
with H. G. Welch, professor of medicine, lecturer in Public Health, author of Overdiagnosed: Making People Sick in the Pursuit of Health.

Sources: Likelihood that a woman with screen-detected breast cancer has had her “life saved” by that screening, NCBI PMID: 22025097, 2011 Dec, full study PDF.

Overdiagnosed: Making People Sick in the Pursuit of Health

From a nationally recognized expert, an exposé of the worst excesses of our zeal for medical testing

Overdiagnosed book cover image
Drawing on 25 years of medical practice and research, Dr. H. Gilbert Welch makes a reasoned call for change that would save us from countless unneeded surgeries, debilitating anxiety, and exorbitant costs.

After the criteria used to define osteoporosis were altered, seven million American women were turned into patients—literally overnight. The proliferation of fetal monitoring in the 1970s was associated with a 66 percent increase in the number of women told they needed emergency C-sections, but it did not affect how often babies needed intensive care—or the frequency of infant death. The introduction of prostate cancer screening resulted in over a million additional American men being told they have prostate cancer, and while studies disagree on the question of whether a few have been helped—there’s no disagreement that most have been treated for a disease that was never going to bother them. As a society consumed by technological advances and scientific breakthroughs, we have narrowed the definition of normal and increasingly are turning more and more people into patients. Diagnoses of a great many conditions, including high blood pressure, osteoporosis, diabetes, and even cancer, have skyrocketed over the last few decades, while the number of deaths from those diseases has been largely unaffected.

Drawing on twenty-five years of medical practice and research, Dr. H. Gilbert Welch and his colleagues, Dr. Lisa M. Schwartz and Dr. Steven Woloshin, have studied the effects of screenings and presumed preventative measures for disease and “pre-disease.” Welch argues that while many Americans believe that more diagnosis is always better, the medical, social, and economic ramifications of unnecessary diagnoses are in fact seriously detrimental. Unnecessary surgeries, medication side effects, debilitating anxiety, and the overwhelming price tag on health care are only a few of the potential harms of overdiagnosis.

Through the stories of his patients and colleagues, and drawing from popular media, Dr. Welch illustrates how overdiagnosis occurs and the pitfalls of routine tests in healthy individuals. We are introduced to patients such as Michael, who had a slight pain in his back. Despite soon feeling fine, a questionable abnormal chest X-ray led to a sophisticated scan that detected a tiny clot in his lung. Because it could not be explained, his doctors suggested that it could be a sign of cancer. Michael did not have cancer, but he now sees a psychiatrist to deal with his anxiety about cancer.

According to Dr. Welch, a complex web of factors has created the phenomenon of overdiagnosis: the popular media promotes fear of disease and perpetuates the myth that early, aggressive treatment is always best; in an attempt to avoid lawsuits, doctors have begun to leave no test undone, no abnormality—no matter how incidental—overlooked; and, inevitably, profits are being made from screenings, a wide array of medical procedures, and, of course, pharmaceuticals.

Examining the social, medical, and economic ramifications of a health care system that unnecessarily diagnoses and treats patients, Welch makes a reasoned call for change that would save us from countless unneeded surgeries, debilitating anxiety, and exorbitant costs.
Read book reviews.

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Overdiagnosis: is looking hard for things to be wrong a good way to promote health?

It’s easier to transform people into new patients than it is to treat the truly sick

If You Feel O.K., Maybe You Are O.K.
It’s easier to transform people into new patients than it is to treat the truly sick.

Early diagnosis has become one of the most fundamental precepts of modern medicine. It goes something like this: The best way to keep people healthy is to find out if they have (pick one) heart disease, autism, glaucoma, diabetes, vascular problems, osteoporosis or, of course, cancer — early. And the way to find these conditions early is through screening. ”

Continue reading If You Feel O.K., Maybe You Are O.K., by H. GILBERT WELCH, NewYorkTimes, 27 Feb 2012.