135 of 137 people found the following review helpful
5.0 out of 5 stars Good Insights -
Conventional wisdom is that more diagnosis, especially early diagnosis, means better medical care. Reality, says Dr. Gilbert Welch - author of "Overdiagnosed," is that more diagnosis leads to excessive treatment that can harm patients, make healthy people feel less so and even cause depression, and add to escalating health care costs. In fact, physician Welch believes...
Published on January 22, 2011 by Loyd E. Eskildson
23 of 34 people found the following review helpful
3.0 out of 5 stars We May Not Need an Intervention: Take Your Medicine and Read It
I learned a lot from this book and recommend it.
The book's thesis is that Big Medicine responds to a number of inputs, and that the response to those inputs, fear, anxiety, and a desire to "do something" leads to tests and procedures that are at best unnecessary and at worst dangerous. These "unnecessary" procedures waste billions of dollars that could be...
Published 24 months ago by Nona
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135 of 137 people found the following review helpful
5.0 out of 5 stars Good Insights -,
This review is from: Overdiagnosed: Making People Sick in the Pursuit of Health (Hardcover)Conventional wisdom is that more diagnosis, especially early diagnosis, means better medical care. Reality, says Dr. Gilbert Welch - author of "Overdiagnosed," is that more diagnosis leads to excessive treatment that can harm patients, make healthy people feel less so and even cause depression, and add to escalating health care costs. In fact, physician Welch believes overdiagnosis is the biggest problem for modern medicine, and relevant to almost all medical conditions. Welch devotes most of his book to documenting his concerns via examples of early diagnosis efforts for hypertension, prostate cancer, breast cancer, etc. that caused patient problems.
Welch provides readers with four important and generalizable points. The first is that, while target guidelines are set by panels of experts, those experts bring with them biases and sometimes even monetary incentives from drug-makers, etc. Over the past decades many target levels have been changed (eg. blood pressure, cholesterol levels, PSA levels), dramatically increasing the number classified as having a particular condition. (Welch adds that prostate cancer can be found at any PSA level - about 8% for those with a PSA level of 1 or less, over 30% for those with a level exceeding 4; most are benign.)
The second is that treating those with eg. severe hypertension benefits those patients much more than treating those with very mild hypertension or 'prehypertension;' the result is treating those with lesser 'symptoms' can easily cause new problems that outweigh the value of the hypertension treatment.
The third is that Welch believes it is usually more important to treat those with disease symptoms (eg. pain) than those without. For example, almost 70% of men 60-69 have prostate cancer, as well as about 10% of those aged 20-29 - a large number are better left untreated because their particular cases involve a very slow-growing form and the side-effects of treatment outweigh the benefits. Welch also reports that a study of over 1,000 symptom-free people that underwent total-body CT screens found 86% had at least one detected abnormality, with an average of 2.8. Many of these abnormalities later disappear (some cancers disappear), while others grow very slowly, if at all. Providing unneeded treatment subjects patients to unneeded pain, risk of adverse outcomes (including death), and unneeded expense.
Examples: Welch cites the example of a mildly hypertensive older man that he treated; unfortunately, while shoveling snow the individual passed out from a combination of sweating and the diuretic prescribed for his high blood pressure. Welch discontinued the man's medication. Similarly, Dr. Welch treated a patient with mild diabetes - the result was she fainted from low blood sugar (the level fluctuates around a mean) while driving just after a meal and was severely injured in an accident. Dr. Welch discontinued her medication as well.
Meanwhile, at the same time that a number of target guidelines have been tightened, the availability and capability of scanning and other detection devices to find abnormalities has also increased. For example, since the early 1990s, Welch tells us that the Medicare per capita use of head scans has doubled, the rates of abdominal scans have tripled, chest scans quintupled, brain MRI rates quadrupled, etc. New biopsy methods for detecting prostate cancer (eg. sampling from 18 points rather than 12 or fewer) also increase the number of benign 'false-positive' diagnoses, probably much more so than true positives.
Why is there so much testing? Dr. Welch attributes it to well-meaning disease advocacy groups, testimonials (eg. ex-Senator Dole regarding his prostate cancer), quality-improvement efforts that include testing as one of their criteria, malpractice awards, hospital/specialist/drug company marketing (beware of these, says Welch), and honest disagreement over its value. He's also concerned about what lower-cost DNA testing will add to the overdiagnosis problem, contending that everyone's genes will reveal heightened susceptibility to some ailments and diseases, with little that can be done despite the knowledge. The author would probably also be concerned about new Medicare requirements to provide a battery of up to 45 medical tests ("The Wall Street Journal" - 1/18/2011). That article also reports that a "New England Journal of Medicine" review of hundreds of preventive-care studies showed that fewer than 20% saved money.
Bottom-Line: Dr. Welch raises an important topic for improving health care while reducing costs. His main recommendation, more data from clinical trials showing the outcomes of choosing one diagnosing standard/method over another, is important and appropriate.
54 of 55 people found the following review helpful
5.0 out of 5 stars Very Important Read,
This review is from: Overdiagnosed: Making People Sick in the Pursuit of Health (Hardcover)Dr. Welch's book is important and a good read. He explains concepts clearly and thoroughly, and the topic is timely and important for Americans, both from a public health (and personal misery) standpoint, as well as a skyrocketing national medical costs standpoint.
I have worked in the medical field off and on over the years, and even worked on a prostate cancer project, so I already knew a fair bit about the prostate cancer screening/treatment debate. I learned even more from Dr. Welch.
One question that I have had for years, and that has never been answered to my satisfaction is:
If a person is being treated for cancer, and they die from the treatment (on the operating table, from the drugs/radiation, etc.), do they count in the "deaths from cancer" statistic? I personally have known many more people who died from the treatment itself than who died from the cancer, and yet that particular topic does not get addressed. Are death rates from prostate cancer (for instance) holding steady because the treatments don't work, or because men are dying from unnecessary treatment and that offsets the successful treatments? (I did notice that the death rates for prostate cancer went *up* with an increase in detection in the figure on page 56.)
Statistics are smoky, and it really helps to know more about the study design. Dr. Welch does a very good job of describing the various studies, and their flaws and strengths. I'm sure it is a huge hot potato to discuss death rates from treatment, but I would be very interested in seeing those numbers broken out.
49 of 51 people found the following review helpful
5.0 out of 5 stars Buy one copy for yourself and another for your doctor,
This review is from: Overdiagnosed: Making People Sick in the Pursuit of Health (Hardcover)I read Overdiagnosed this morning, and I strongly urge you to read it, too. If you've ever wondered why our country's healthcare costs are skyrocketing even though our health outcomes lag behind the rest of the industrialized world, this book has the answers. We are overtested, overdiagnosed and overtreated. But sadly and paradoxically, this intensive use of "preventive" medicine has not improved our physical health or sense of well being -- it has diminished it.
Dr. Welch builds a strong case that Americans are overdiagnosed in a clear, concise and compelling way. He provides anecdotal accounts of people who were seriously harmed by the overzealous use of modern, high tech testing. And he backs these stories up with findings from landmark medical research studies. As we move from chapter to chapter and disease to disease, we see the same patterns emerge: thresholds for "illness" are lowered and suddenly tens of millions of people are diagnosed and treated for mild or nonexistent "diseases" that never would have harmed them.
Dr. Welch identifies the key players who brought American medicine to this sorry state -- big pharma and medical products manufacturers hungry to increase profits, doctors who order unnecessary tests to avoid malpractice lawsuits, and overzealous patient advocacy groups who press for action in the absence of any scientific evidence of improved outcomes.
Dr. Welch explains key concepts like "lag time bias" and "overtreatment bias" that enable you to see why the benefits of aggressive preventive medicine are far less than you have been led to believe. Once you understand terms like these, you will never again be swayed by misleading advertising or public health campaigns. Instead, you will be able to make decisions about your own health care in a rational, intelligent, and informed way.
In short, if you read one health related book this year, it should be "Overdiagnosed." Buy one copy for yourself and another for your doctor.
24 of 25 people found the following review helpful
4.0 out of 5 stars Why Looking for Diseases in Seemingly Healthy People Often Doesn't Benefit Patients,
This review is from: Overdiagnosed: Making People Sick in the Pursuit of Health (Hardcover)Dr. H. Gilbert Welch challenges the standard practice of preventative testing that most patients would never think to question. He disputes the current belief that it's always desirable and beneficial to obsessively screen healthy people for potential illnesses and describes how actively pursuing illness can actually be harmful to the patient being tested.
Just why is it bad to discover that people have diseases they don't know about and that have yet to create any symptoms? A few reasons discussed in this book are:
1) The medical-industrial complex continually lowers the numbers to give people more diseases.
2) Treating patients on the mild or borderline end of the disease spectrum often causes more harm than good.
3) The side effects of the treatments for patients with mild to moderate forms of a disease can be worse (and cause more discomfort and disruption) than the actual disease especially if they are asymptomatic.
4) Most people have "abnormalities" that would never cause them problems and are only diagnosed thanks to advanced medical imagining.
5) There is the very real risk of false positives, causing patients to be treated for things such as prostate and thyroid cancer that they never actually had. This is not only expensive but can cause lasting harm in addition to the negative effects of the treatment.
6) Some abnormalities that are technically classified as cancers are genetically destined never to progress or cause a person symptoms.
7) Due a patient's age or other medical conditions, s/he will die of something else for the cancer progressed enough to cause symptoms or discomfort. So, diagnosing and treating them will not benefit the patient. In fact, it will only harm them emotionally, financially, and physically.
8) Rapid growing cancers that are also often resistant to treatment frequently are not caught by annual (or continual) preventive screenings because they develop so rapidly and can appear between screenings.
9) Actively searching for disease in asymptomatic patients further strains an already overburdened medical system.
10) The discovery of pre-existing conditions can result in the loss of medical insurance and the refusal for insurance companies to cover the costs of treatment.
11) The potential benefit of treatment commonly falls short of the actual benefit by a significant amount.
12) Many of the motives behind the push for preventative screens are not altruistic (i.e. motivating factors include profit and fear of lawsuits).
13) Patients are often encouraged to seek preventative screenings based on personal anecdotes rather than solid medical facts.
And the list goes on . . .
The author's conclusion is not to avoid screening and medical treatments resulting from a positive test. Instead he councils patients to weigh the negative outcomes against any potential benefits before choosing to be screened. He also encourages patients to give careful consideration before consenting to treatment for any asymptomatic "abnormality" discovered when testing for other complaints.
Chapter 1 discusses high blood pressure.
Chapter 2 discusses diabetes, high cholesterol, and osteoporosis.
Chapter 3 discusses medical imaging and the myriad of conditions such as bulging discs, blood clots, abdominal aortic aneurysms, damaged cartilage and gallstones that are often discovered when testing for other conditions.
Chapter 4 discusses prostate cancer, including the author's own reasons behind opting out of screening for it.
Chapter 5 discusses other cancers such as thyroid and colon cancer.
Chapter 6 discusses breast cancer.
Chapter 7 discusses "incidentalomas" that might or might not be cancerous.
Chapter 8 discusses other screenings such as cardiograms and ultrasounds.
Chapter 9 discusses genetic testing to determine if patients have elevated risks of developing certain diseases.
Chapter 10 is the author's conclusion.
The epidemic of overdiagnosis makes for an interesting albeit disturbing read. The statistics and charts occasionally make for dry reading, but overall the writing is accessible to all of us ordinary consumers of medical services.
22 of 23 people found the following review helpful
5.0 out of 5 stars Everyone who sees a doctor should read this book,
This review is from: Overdiagnosed: Making People Sick in the Pursuit of Health (Hardcover)I am a family physician. Recently I was told that I do not have enough time to explain risks and benefits of screening to my patients. I try to take the time, but many have been convinced by media and friends that 'good medicine' means 'early detection.' My risk and benefit speech is not what many want to hear. It's so much easier just to be told what to do. I hope Dr Welsh's insight spreads.
22 of 23 people found the following review helpful
5.0 out of 5 stars Don't bury your head in the sand,
This review is from: Overdiagnosed (Kindle Edition)« Overdiagnosed » turns the slogan "don't bury your head in the sand", used for promoting screening, against it. Living examples and hard facts provided by Dr Welch give evidence that the more you look for disease among healthy people, the more you find pseudodisease that would not have had any damagable consequences for your health. This happens for high blood pressure, diabetes, hypercholesterolemia, osteoporosis, gallstone, damaged knee cartilage, bulging discs, abdominal aortic aneurysms, blood clots, cancer, and much more ! I bet that pretty soon, all healthy readers will thank Dr Welch for his chapter « We confuse DNA with disease ; how genetic testing will give you almost anything ». Delightful examples including wrong dogmas in other fields enlight the demonstration. Drawbacks due to overdiagnosis are so convincing that you easily catch how dwelling on the diseases you may (or may not) develop actually poisons life. Anxiety leads to too much medical care that leads to overdiagnosis that leads in turn to side effects of overtreatment. Before reading this book, you may wrongly fear disease. After reading it, you wisely fear medical misappropriate care. Here is the conclusion : Enjoy living healthy to be strong enough for facing adversity when it (ever) comes.
20 of 21 people found the following review helpful
5.0 out of 5 stars The Fallacy of Early Detection,
This review is from: Overdiagnosed: Making People Sick in the Pursuit of Health (Paperback)This book will probably appeal to people like me, who have already been questioning the value of endless screening tests, but I hope others will read it as well. It is a large dose of sanity in the face of all the pressure from doctors, advocacy groups for various diseases, public service ads and commercials from companies offering screening tests who tell us we need to be screened because "early detection saves lives." Usually they throw in some stories of people who got screened, got treated and are still alive. They are all quoted saying "Early detection saved my life."
But did it? Or did it just turn them into patients years before their "disease" would have manifested itself? Worse yet, maybe that tiny growth detected on the X-ray would NEVER have turned into actual disease. In that case, they did not need any treatment and may have been harmed by the treatment they received. Dr. Welch calls this "overdiagnosis."
Dr. Welch points out that these "success" stories lead to more screening which leads to more useless treatment. Proponents often cite the increased "cure" rate of those who are screened versus those who are not. Logically, the time between diagnosis and the time when the patient is considered "cured" (say, five years with no recurrence) will be greater if a tumor was found several years before it would have manifested as symptoms. With or without screening, a tumor would grow (or not grow) at the same rate. Without screening, a tumor that grows will be discovered when the patient has symptoms. That's a later diagnosis, but the course of the disease is the same and early treatment might make no difference at all.
MY MAMMOGRAM STORY
I am in my middle 60s and had always resisted getting a mammogram until recently. I had changed doctors and my new doctor gave me a referral and I decided to do it this time. I think it was mostly out of curiosity and because Medicare would pay for it (a wrong reason, I know!). The screening was done at a huge hospital complex (Beaumont Hospital in Royal Oak Michigan). The procedure was fast and not too unpleasant, but I was surprised to get a phone call a few days later telling me I needed to make another appointment for more views. I asked why and got no real answer, other than the Radiologist wants more views. I said I needed more information before I would come back and they said to call my doctor. I did that, and his staff person had to search for any information about my mammogram, but finally found what the hospital had sent and it merely said that the results were inconclusive for the left breast. This does not tell me what was inconclusive. I then received a letter from the hospital, which said the initial findings showed "a need for additional imaging studies, such as additional mammographic views, ultrasound or MRI for a complete evaluation." This sounded to me like the start of a cascade of expensive and possibly invasive and dangerous services which I did not want. I got several more calls from the hospital urging me to make another appointment, but I was not satisfied with the lack of real information as to why I should do that. Finally another woman called me who would only say she was "Sharon," so I don't know her position, but she must have been a supervisor because she did tell me more (there was an "asymmetrical density " in the left breast), but would not name the Radiologist (I later got her name from my Medicare payment info online). Sharon said (in effect) I was likely called back because this was my first and only mammogram and they had nothing to compare it with. I subsequently received a certified letter from the hospital, which I take to be their "CYA" letter in case I turn up with cancer and sue them. I finally sent them my own certified letter explaining why I was not returning and asking for access to the images and notes from my mammogram. They have never responded.
I do breast self-exam and there are no lumps or any abnormality. I have no symptoms and I feel fine. I am more willing to trust my own instincts that I do not have brest cancer than I am willing to trust the people at the hospital. My only regret is getting the mammogram in the first place.
To hear all the hype about mammograms, you'd think they somehow PREVENTED cancer, whereas they do no such thing. They are X-rays of the breast and the "findings" are the opinion of a Radiologist who does not see you or examine you. I find Radiology a strange kind of medical specialty. It does not involve patient contact, but is based on a person (presumably the Radiologist) studying images and coming to a conclusion. In the book, Dr. Welch has a horrific story of a pregnant lady whose imaging screening could not image one of her baby's feet. The Radiologist decided the baby probably had a club foot. The poor mother-to-be drove herself crazy learning all about club feet and imagining what life would be like for her deformed child. When the baby was born, both feet were perfect. The point is, these images are often going to find anomalies that can't be definitively said to be deformity or disease. But the findings WILL lead to a lot more medical services.
I think Dr. Welch actually underestimates one of the consequences of this and that is the expense. Whether it's the patient paying (increasingly the case) or insurance or Medicare, screening leads to a lot of expensive services that are not needed and can do a lot of harm. Men treated for early signs of prostate cancer can become permanently impotent, and the worst of it is their prostate cancer may never have progressed to a point where they would have symptoms. Many men with prostate cancer eventually die of something else because the cancer is so slow growing, or may not grow at all. Particularly with prostate and breast cancers, studies involving autopsies show many people have small cancers they never knew they had and which never caused any symptoms.
Dr. Welch works for the VA, which is a single-payer government-funded system in which the doctors have no financial incentive for overtreating patients, but I think lots of doctors are biased in favor of treatment when it may not be needed because of the extra income it brings. Radiologists who don't even see the patient have every incentive to say they "need more views." The hospital has every incentive to encourage women to come for mammograms, then to do more imaging if anything at all is found on the screening X-rays.
Dr. Welch also barely mentions the fact that X-rays CAUSE cancer! Yes, we've all heard about how tiny and harmless those doses are in a mammogram or other X-ray, but the effect is cumulative. That is one reason I was not eager to "have more views" taken. When those dose amounts in a mammogram are mentioned, how many "views" are they based on? Why don't screening services release actual information of the dosage of each view? How do I know their machines are working properly or that their technicians are competent? Why should I trust these medical providers on this subject when they have so much incentive to encourage "more views?"
Too much worrying about our health and visiting doctors when we are not sick is adding to our bloated health care bill in the US. Maybe we should just accept our own mortality and not seek ever-more information from inside our bodies via screening. People talk about the supposed benefit of finding disease early, but never about the harm of pursuing tiny ambiguous anomalies leading to treatment that could be unnecessary and surely is expensive.
This book is very well-written, with clear explanations, nice graphs to help illustrate the points made, and plenty of eye-popping examples. Before you buy in to "early diagnosis" and give into the pressure to get screened, read this book and use your head. Dr. Welch makes his case.
18 of 19 people found the following review helpful
5.0 out of 5 stars Superb,
This review is from: Overdiagnosed (Kindle Edition)Overdiagnosed peers into the triad of interests that subject persons not at risk for serious illness to unneeded worry, testing, and potentially harmful intervention. The three are: (1) physicians who sustain at least parts of their practices by over-screening and over-diagnosing, (2) pharmaceutical and medical-device companies who reap the benefits of broad-range screening and early treatment for discovered "abnormalities" that may never (whether treated or not) develop beyond the phantom stage, and (3) the legal system's retrospectoscope that imposes liability on health-care professionals for the relatively rare missed diagnosis (this latter reality prompts even those physicians who do not directly benefit from over-screening and over-diagnosis to practice "defensive medicine," resulting in a multiplier effect that amplifies the costs to patents and to an already overburdened health-care system). Sadly, the media, which hardly ever looks at issues in depth, magnifies the problem because of their constant calls for more and more and earlier and earlier screening of folks who have no identifiable symptoms.
Simply put, as Dr. H. Gilbert Welch and his colleagues tell us in a lucidly written and well-supported examination of the problem, the over-diagnosers and those who benefit from over-diagnosis exploit (knowingly or unknowingly) the natural quest for perfect health and the concomitant rush to fix blame on others when things go wrong.
Overdiagnosed should be read by everyone: health-care and legal-system professionals, the media, and, of course, potential patients everywhere.
20 of 23 people found the following review helpful
5.0 out of 5 stars Excellent sequel to "Should I Be Tested for Cancer?",
This review is from: Overdiagnosed: Making People Sick in the Pursuit of Health (Hardcover)Welch is the author of the excellent Should I Be Tested for Cancer?: Maybe Not and Here's Why. This book extends the same question to all other tests. Welch has observed increasing overdiagnosing that has turned benign abnormalities into unnecessary treatments that do more harm than good.
The causes of overdiagnosing include: 1) health care providers economic incentives; 2) disease advocacy groups who truly believe early diagnosis is always better (it is not, the majority of aggressive cancers are uncurable whether diagnosed early or not); 3) doctor ratings that are based on the percentage of patients they test for various conditions; and 4) malpractice suit.
A couple of trends have exacerbated overdiagnosing. The first one is the reduction in disease diagnostic cut-off points. For instance, hypertension (high blood pressure) cut-offs have been reduced from 160/100 (systolic/diastolic pressure) to 140/90. The resulting US patient population has increased from 38 million to 52 million. The cut-offs for high cholesterol has been lowered from 240 down to 200. This has boosted the patient population from 49 million to 92 million. The experts who made those decisions invariably have financial ties to the drug companies who market the drugs treating those conditions. The milder your condition the more you will be a victim of overdiagnosing as you won't benefit from the treatment because you are fine; but, you will suffer the side effects.
The other trend exacerbating overdiagnosing is technology. MRI scans detect the minutest anomalies. MRIs will find knee meniscal damages in 40% of the healthy population. MRIs will detect bulging lumbar discs in 50% of healthy people. Those MRI scans result in overdiagnosing including harmful surgeries. The diagnostic technology has exacerbated the supposed prevalence of diseases. In table 3.1 on page 42, Welch shows that the findings of blood clots in lung and leg has increased between 3 to 5 fold vs traditional clinical exams. But, we are not 3 to 5 times sicker. The difference is finding smaller benign blood clots that have little health implications.
Overdiagnosing becomes embedded in the system when an entire population is motivated to get tested. This is true for many of the cancer screening tests (breast, prostate, colon). In chapter 4, Welch addresses the bad trade off associated with prostate cancer screening. The graph within figure 4.1 on page 48 is amazing regarding prostate cancer prevalence. You can turn it into a simple rule of thumb: your age (divided by a 100) is roughly equal to the probability someone your age has prostate cancer. So, if you are 50 the corresponding probability is 50%. Yet, only 3% of the male population dies from prostate cancer. And, this mortality rate is not affected whether one gets treated or not. Thus, most prostate cancer treatment qualifies as overdiagnosing-overtreating. And, the latter has dire consequences. The most common treatment is to remove the prostate; and 50% of patients will suffer impotence, 33% incontinence, and 0.2% death. As a result, the U.S. Preventive Services Task Force (USPSTF) does not recommend prostate screening.
Welch observes the same trends with thyroid cancer as for prostate cancer. It is extremely prevalent as we age. And, it is mostly benign (mortality rate is very low). Yet, it is much overdiagnosed. And, treatment (removing thyroid gland) has negative consequences (hoarse voice, trouble swallowing, disruption of calcium metabolism, and having to replace the thyroid hormone for the rest of one's life).
Welch reviews the trade-offs (benefits vs consequences of overdiagnosis) for many other cancers. He reaches similar conclusions based on objective arguments. On page 78, table 6.1 he shows who benefits from mammography for different age groups of women. And, only 0.05% to 0.2% benefit (depending on age). This means that over 99.8% of women will be exposed to overdiagnosing potentially leading to entire breast removal.
Breast cancer screening is the most politicized of cancer screening. In 1997, when a panel of experts from the National Cancer Institute (NCI) after reviewing all the data available at the time recommends that women in their 40s and 50s should not undergo mammography, it causes a political storm that culminates into a Senate vote. The latter voted 98 to 0, supporting breast cancer screening for women 40 and older. In 2009, Congressional hearings contemplate shutting down the USPSTF only because it recommended women starts screening at 50 instead of 40. Regarding medical policies politicians trump scientists!
Current cancer screening does not differentiate well between aggressive cancers and indolent ones. Welsh illustrates the scale of overdiagnosis for several different types of cancers. In each case, the graphs show a similar trend. The rate of new cancers diagnosed grows rapidly. Meanwhile, the mortality rate stays flat. The difference in the slope between the two lines captures the rate of overdiagnosis.
Welch is also concerned about the retail commercialization of genetic testing. You can get analysis of your genetic propensities from companies such as 23andMe or deCODEme. Welch thinks this is an extreme form of early diagnosis that will result in overdiagnosis. "Because everybody is at risk for something, it's a strategy that will make literally all of us sick." Welch makes a distinction between genotype (your genes) and phenotype (your physical properties). Your phenotype depends on your interaction with environmental and behavioral factors, your genes, and pure randomness. Thus, genotype is far from determining your phenotype which ultimately triggers your suffering certain diseases or not. For only a small minority of diseases are genes a strong predictor. For the majority of them, they are not. Even when a given gene suggests your risk of a certain disease is 3 times normal; it still does not mean anything if the prevalence of that disease is very low (ie. 3 x 0.1% prevalence = 0.3% personal risk). The latter underlies the difference between relative risk and absolute risk. In this last example, the person's relative risk was 300% normal level. But, that person's absolute risk was still very low. She had a probability of never getting that disease of 99.7%.
When you evaluate the benefits of screening, you should focus on what was the change in absolute mortality rates between test and controls. And, if this difference was material also focus on how many persons had to be overdiagnosed and harmed by overtreatment to achieve this improvement in mortality risk. We rarely have this information for many of the most common tests.
Welch recommends you don't get screened unless you have symptoms. By doing so, you will greatly eliminate overdiagnosing. Yet, you can still catch diseases early enough when your symptoms are mild.
If you find this subject interesting, I also strongly recommend the two excellent books by Norton Hadler: The Last Well Person: How to Stay Well Despite the Health-Care System and Worried Sick: A Prescription for Health in an Overtreated America (H. Eugene and Lillian Youngs Lehman).
9 of 9 people found the following review helpful
5.0 out of 5 stars Deserves Six (******) Stars,
This review is from: Overdiagnosed: Making People Sick in the Pursuit of Health (Hardcover)This paradigm-shifting book should be read by everyone, twice. And then, if you don't agree with the author, read it again.
Not only is the information important, but the writing is clear and occasionally funny.
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Overdiagnosed: Making People Sick in the Pursuit of Health by H. Gilbert Welch (Hardcover - January 18, 2011)
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