Preventive medicine may not always help patients

If there’s one thing everyone agrees on, it’s that preventive care is always a good thing. Well, I’m a doctor and I’m afraid of preventive medicine.

The theory behind preventive medicine is sound. It is better to treat prevent disease than to treat it. It is better to refrain from smoking and never get lung cancer than it is to treat lung cancer. It is better to refrain from alcohol abuse than to treat alcoholic cirrhosis of the liver. In each of those cases, avoiding a behavior known to cause the disease is highly effective in reducing the incidence of the disease.

But not all preventive medicine is about avoiding behaviors known to cause diseases. Preventive medicine has held out the possibility of avoiding naturally occurring diseases by correcting hormone, mineral or other imbalances through eating specific foods, taking supplements or using medication. Many of these preventive efforts have not only been unsuccessful, they have created problems of their own, sometimes the very problems they were meant to prevent.

The paradigmatic example is estrogen replacement therapy. Menopause, characterized by a lack of estrogen, is associated with increased risk of a variety of health problems including heart disease and osteoporosis. The reasoning behind estrogen replacement therapy was that if heart disease or osteoporosis are associated with decreased estrogen, replacing that estrogen will reduce heart disease and osteoporosis. There was some experimental evidence supporting that theory, but not a lot. Nonetheless, estrogen replacement therapy became the standard of care well before large scale, long term studies could be completed. It was preventive therapy; how could it cause any harm?

Merely replacing a missing hormone is not as simple as it sounds. Hormones, like many other substances in the body, are involved in more than one system. Indeed, lots of substances play multiple roles in multiple systems. Adding back the missing hormone can have an impact far beyond the system it was designed to protect and that impact can be harmful. The data is not final, but it appears that adding back estrogen increases the risk of breast cancer. And while estrogen replacement did have a beneficial effect on bone health, large scale, long term studies have not delivered the promised benefit of reducing the risk of heart disease. Routine postmenopausal estrogen replacement is no longer the standard of care; it is reserved only for specific situations in which the benefit is judged to be worth the risk.

With routine estrogen therapy contraindicated, the search continued for non-hormonal methods of preventing osteoporosis. Biphosphonates appeared to promote bone health without the side effects of estrogen. Again, large scale, long term studies were lacking, but it was preventive therapy; how could it cause any harm? Unfortunately, it has turned out that biphosphonates may not promote bone health, but may weaken bones. The biophosphonate Fosamax has already been linked to osteonecrosis (bone destruction) of the jaw, and now it appears that long term use of Fosamax may result in severe weakening of the femur bone (the thigh bone) leading to fractures that during activities as simple as walking.

Reversal of deficiencies associated with aging is not the only place where preventive medicine has gone wrong. Preventive medicine also rests on the premise that early diagnosis is better than late diagnosis, and that anything that increases the likelihood of early diagnosis must be beneficial. The most spectacular example of that faulty reasoning is the PSA (prostate specific antigen) test. Since increased PSA is associated with prostate cancer, doctors began recommending routine PSA screening, despite the fact that there were no large scale, long term studies demonstrating benefit. It was preventive medicine; how could it cause any harm?

Listen to what the test’s inventor, Dr. Richard Ablin, has to say about its use: “I never dreamed that my discovery four decades ago would lead to such a profit-driven public health disaster.”

According to Dr. Ablin:

… [T]he test is hardly more effective than a coin toss. As I’ve been trying to make clear for many years now, P.S.A. testing can’t detect prostate cancer and, more important, it can’t distinguish between the two types of prostate cancer — the one that will kill you and the one that won’t.

Instead, the test simply reveals how much of the prostate antigen a man has in his blood. Infections, over-the-counter drugs like ibuprofen, and benign swelling of the prostate can all elevate a man’s P.S.A. levels, but none of these factors signals cancer. Men with low readings might still harbor dangerous cancers, while those with high readings might be completely healthy.

Millions of men have been subjected to unnecessary biopsies, and harmful treatments, and billions of dollars have been wasted on this failed exercise in preventive care.

What can we learn from these and other similar debacles? We need to reexamine the basic premises of preventive medicine. Sure it is better to prevent disease than to treat it, but that does not mean that reversing the metabolic changes that accompany a disease will prevent it or will prevent it without causing serious unforeseen complications. Sure it is better to treat early stage cancer than late stage cancer, but a screening test that makes lots of mistakes can be worse than no screening test at all.

Most importantly, we must never forget that preventive medicine is a branch of medicine, in the exact same way that cardiology and neurology are branches of medicine. As such preventive medicine must be held to the same standards; any treatment, even a preventive treatment, must be tested in large scale, long term studies before being put into routine clinical use. Preventive medicine, like other branches of medicine, has the power to harm as well as to help. We ignore that fact at our own peril.

Amy Tuteur is an obstetrician-gynecologist who blogs at The Skeptical OB.

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  • http://twitter.com/Camsbridge Camsbridge

    Surely this more of a criticism of a lack of evidence based decision making rather than preventative medicine itself?

  • http://www.skepticalob.com Amy Tuteur, MD

    “We docs get fooled repeatedly by using surrogate endpoints (bone density, prostate cancer detection) instead of medically important endpoints (fractures, death from prostate cancer) in studies.”

    Exactly.

    In addition, we often confuse correlation with causation. Finding a low level of a micnonutrient in association with a certain form of cancer (or any other disease) does not mean that the deficiency caused the cancer. We rush to recommend supplements without bothering to do the long term studies necessary to establish that the supplement prevents the disease in question.

  • jsmith

    Good post. We docs get fooled repeatedly by using surrogate endpoints (bone density, prostate cancer detection) instead of medically important endpoints (fractures, death from prostate cancer) in studies. Of course the imperative to do something (even if that something might turn out to be wrong) is a big factor here. Doubt this will change much in the near future, Obamacare nothwithstanding.

  • http://www.kevinmd.com/blog/2010/03/mammogram-screening-divides-doctors-patients.html DrLemmon

    I enjoyed your post, good points.

    I noticed that the Reclast study in NEJM showed a NNT of 91 to prevent 1 hip fracture over 3 years. Number needed to harm was 125 (serious A-fib) and mortality was actually slightly higher in the Reclast group. Cost to prevent that 1 hip fracture, over $310,000.

    Not only did the Woman’s Health Initiative show that HRT was not beneficial, it also showed a high fiber, low fat diet with 5 servings of fruits and vegetables was of no benefit. http://junkfoodscience.blogspot.com/2007/10/junkfood-science-exclusive-big-one.html

    Yet we push ineffective costly drugs onto patients all the time and hit them with guilt trips over dietary habits that are irrelevant.

  • http://www.morethancarrots.com Cheftometrist

    Perhaps it makes sense to categorize preventation efforts as interventional vs. non-interventional. Smoking cessation, dietary modification, exercise, etc are non-interventional in my mind (ie lifestyle changes), where there’s potential benefit with much less potential risk. However, interventional prevention, like HRT or Fosamax, depends much more on the quality of the evidence that is used to support it because it carries greater potential for risk.

  • Marc Gorayeb, MD

    I agree with the thrust of your argument in principle. However, I think the issue is far more complicated that what you suggest.

    First, although there are sound arguments that the PSA test is being used inappropriately, it may also be the ‘hook’ that is ultimately responsible for the lower prostate cancer death rate in the US compared with the UK, for example. Although many more men in the US may be suffering from iatrogenic impotence and/or incontinence, they are also surviving prostate cancer at a higher rate.
    I wouldn’t be too quick to throw out the PSA test. And recommending linking PSA tests with ‘counseling’ is a loaded concept. Is the ‘counseling’ designed to prevent a patient from getting the test? Or is it to assist the patient in interpreting the result? If it’s the former, then we risk seeing a resurgence in the prostate cancer death rate.

    Second, in many cases, it is simply not practical to study a treatment’s effect on medically important endpoints, such as survival. Use of surrogate endpoints, when based on sound scientific reasoning, is a perfectly valid way to draw at least some important conclusions about the benefit of a treatment. The danger of insisting on “large scale, long term studies” using “medically important endpoints” is that potentially life-saving or life-extending innovations will either be long-delayed, or may never even see the light of day.

  • Jadedmd

    You’re being so hard on fosamax, which actually has been shown to prevent fractures in studies, not just increase bone density. I do think you have overemphasized the risk

  • http://www.skepticalob.com Amy Tuteur, MD

    “it may also be the ‘hook’ that is ultimately responsible for the lower prostate cancer death rate in the US compared with the UK, for example.”

    But the scientific evidence shows that is not the case. Large studies have made it clear that cancers diagnosed by PSA do not have a lower death rate as compared to those diagnosed by other methods such as physical exam.

  • http://www.musclerepairshop.com Butch Phelps

    I liked your article, however, throwing in all preventative care into one pile is wrong. The diseases you are speaking of, as well many diseases people suffer every day, are the accumulative effect of their entire lifestyle. I agree that preventative care cannot reverse in a short period of time, what a person has done to themselves over their whole life. Preventative measures must start at a young age. We must teach, and practice, healthy nutrition in our elementary schools. We must increase the activities in our children’s lives so they will remain active through out their lives. What is wrong with preventative care is we are trying to solve in a test tube a defiency caused by the lack of education in our society. I also believe that training for personal trainers, many massage therapist, and physical therapist are either too short or too inaccurate. I see many patients who has gone through months of physical therapy with no improvement because the program still uses antiquated techniques. Most personal trainers are certified in 1 day. Mnay massage therapist are trained in 6 months without a full grasp of the muscles of the human body. This is dangerous to the public as well. Until we take preventative care seriously, nothing will change.

  • http://www.closerlook.com DaveO

    Amy,

    I wish you had spent more time going down the path of suggesting where “preventative medicine is great in theory” is great in practice rather than just revisiting the problems with HRT and the PSA test. Are we limited to simply reacting to patient endpoints when they need expensive treatment? It seems the only way to significantly reduce healthcare costs in this country is to increase wellness.

    I like cheftometrist’s differentiation between intervention and non-intervention, but even the non-intervention requires some serious behavioral change coaching.

    Where is prevention working?

  • http://www.musclerepairshop.com Butch Phelps

    By promoting behavorial changes earlier in a person’s life, there will not be a need for so many HRT and PSA test. Having said that, it is a community problem and not just a doctor problem. Medicine tends to be more reactive mainly due to the overwhelming amount of people who are sick. As a community we need to stress more training for trainers, therapists, nutritionists, and better food quality in our schools.

  • R Lee Smith

    Dr. Ablin may have invented the PSA test but that doesn’t make him an authority on using it. I would recommend all men who care about their health discuss PSA testing with their urologists. PSA and mammograms are under attack right now, but there are hundreds of thousands of us who aren’t statistics and who have had early stage cancers detected with these screening tools and then investigated and made informed decisions about what to do next. As far as saving lives, the European studies reveal a 30% reduction in death from Prostate Cancer because of PSA testing. You conveniently (for your article) forgot to report that.

  • http://www.musclerepairshop.com Butch Phelps

    I would agree that the PSA test and mammogram should be kept. I am afraid that when most people read that a 30%reduction in the death is due to the test, is a false assumption. The test may have detected the cancer early enough to save the lives, but the European diet and lifestyle is contributes heavily to the reduction as well. Prostate and breast cancer could be greatly reduced by reducing obesity, improving the activities people have in their lives. The best cure for cancer is to spend your life eating and living a lifestyle that is conducive to cancer free living. Let’s be more proactive and not settle for reactive.

  • R Lee Smith

    Butch Phelps comments are well taken — is may well be the PSA and mammography screening are most effective in collaboration with the appropriate life style and that would certainly be a valuable interaction to study. In addition what most of the massive surveys seem to ignore is the type of follow up that occurs once a red flag is raised by screening. In this regard the recent studies are all already out of date as specialists in treating prostate and breast cancer have been making advances year after year and long term studies can only look at the past and are at best of historical interest. In other words, it would seem foolish for someone to wait for certainty but rather all should gather the best info that they can about there prostate via PSA and breasts via mammography. We are not statistics but individuals, and many many individuals have benefited from screening knowledge and follow up.