Every time I think that the question of PSA testing has been laid to rest, another outcry arises, sometimes pro and sometimes con. I realize that what we are dealing with here is a medical belief system, and belief systems are notoriously impervious to data and facts. I can recall the brouhaha that arose when one group announced that a clinical study showed no benefit of mammograms to women in the 40 to 49 year old age group.
Let us begin again by realizing that no one argues about the speed of light, or whether or not Albany is the capital of New York State, or if 7 x 8 = 56. No one usually argues about agreed-upon facts that can be measured. The problem arises when two people try to fit the same data into two different heuristic structures, because your theoretical picture will frame and interpret the data you view, as all epistemologists acknowledge. There is even more argument when we try to interpret or predict the result of an intervention on human behavior: we still cannot agree on whether or not the data shows that teaching about sex education and contraception in high school encourages high school students to have sex. As a general rule, when the data does not lead to an immediately verifiable conclusion (viz. the question of global warming) there is a tremendous amount of heat generated in the argument/discussion with correspondingly little light.
The broadest discussion to date about the pros and cons of screening with the PSA is contained in this month's issue of the Annals of Internal Medicine (17 July, 2012) , vol. 157, no. 2. There are three articles: The USPSTF (U.S. Preventive Services Task Force) recommendation against PSA screening, with the proviso that the final decision should be one of "shared decision making" between the doctor and the patient (pp 120-134), a shorter review which concurs with the recommendation of the USPSTF (pp 135-136), and an equally short review that opposes the recommendations (pp 137-138). I will summarize the three articles from a strictly scientific point of view ---i.e. based on the data cited, and then try to illustrate where personal beliefs and projected feelings about the quality of life with and without treatment may have crept into the discussion. I will also carefully point out the unknowns in this decision making. And let us not forget that the USPSTF recommendations are only recommendations, and each patient will make a decision that is ego-syntonic with his own medical belief system.
First a caveat. In my practice I have never seen a wife permit her husband to do "watchful waiting" once a biopsy shows prostate cancer. So if you are a husband who would not agree to any treatment, then don't ever do the PSA test.
1) The only screening method referred to in all the studies is the serum PSA, and not a rectal exam.
2) More men die with prostate cancer that from prostate cancer. In the latest autopsy study, 70% of men in their 70's have microscopic foci of prostate cancer.
3) Some groups are at increased risk for prostate cancer: black men and men with first degree relatives who have or have had prostate cancer.
4) If we define "overdiagnosis" as the detection by PSA of a tumor that will not spread and cause symptoms in the patient's lifetime, then the two largest trials suggest overdiagnosis rates of 17% to 50%.
5) No study reported on the effect of screening on the development of metastatic disease.
6) In looking at all the studies, the chance of a non-screened man of dying from prostate cancer in 10 years is 5 in 1,000. The chance of a screened man dying is either 4 or 5 in 1,000, so the net benefit is between 0 and 1 man per 1,000 men screened.
7) NO study showed a reduction in all cause mortality(!) The one study that showed a slight decrease in mortality from prostate cancer showed an increase in deaths from other causes, usually cardiovascular, so there was no net extension of lifespan that resulted from PSA screening.
8) When the PSA cutoff is between 2.5 and 4.0, the false positive PSA rate is 80%.
9) Overdiagnosis makes screening appear to save lives when it does not do so.
10) The median follow-up time was 10 years.
11) Because of lead-time bias, patients diagnosed earlier by asymptomatic screening appear to live longer with cancer. This is a problem with all screening methodologies for all fatal diseases.
12) The American Cancer Society and the American Urological Society both recommend informed decision making rather than routine PSA screening.
13) Radiotherapy and surgery both cause urinary incontinence in 20% of those so treated and erectile dysfunction in 30% (on the average).
14) Radiotherapy can also cause chronic diarrhea and/or colonic irritability.
15) "We need to practice medicine on the basis of evidence and not on the basis of faith."
And again, despite all recommendations and readings, there is no substitute for a full discussion with your family doctor of your likes, your dislikes, your wishes, your fears, and your desires. You should never feel pressured into making a decision about your health with which you do not feel comfortable. It is your body and your mind, and you have to live comfortably with them both. And once you make a decision, please don't second-guess yourself. (You have enough well-meaning friends who will do that for you.)
Wednesday, July 18, 2012
Monday, July 16, 2012
Who Needs Vitamin D Supplements, and How Much?
Vitamin D seems to be the "hot" new supplement, whether it is our old friend contained in cod liver oil, or in calves' liver,or in pills of Vitamin D, or in the form of Vitamin D1, D2, or D3. There was a recent overview and critique of the many studies of this vitamin which was published in the New England Journal of Medicine by R.P. Heaney: NEJM vol 367, no. 1, pp 77-78 (July 5, 2012). I will try to summarize his article as well as to add some observations of my own, and I will make no statements that cannot be verified by reference to the scientific literature or that have not been validated by clinical studies and tests. (Standard disclaimer---I have no vested monetary interest in whether or not you buy and ingest any form of Vitamin D.)
You should all be made aware that Vitamin D is similar to Vitamin A and vitamin E in that it is fat-soluble and hence stored in your liver. Unlike the B vitamins or Vitamin C , it is not immediately excreted by your kidneys if ingested to excess, but rather the excess is stored in your liver. In fact so much Vitamin A and D can be stored in the liver of an animal that Eskimos have died from ingesting the liver of polar bears that they have killed. And we know from separate clinical studies that hypervitaminosis A can harm you, and that excess dietary supplements of Vitamin E can increase your risk of having a heart attack. So far the only demonstrated damage from prolonged ingestion of excessive amounts of Vitamin D is band keratopathy, or deposits in your cornea.
Vitamin D is needed, along with calcium and phosphorous, to form bones that are not thin and subject to fracture (osteoporosis) and that do not bend under the normal load of supporting the body (rickets). The process of normal bone formation is regulated by parathyroid hormone, which is secreted by four glands situated in your thyroid gland, usually two on each side. Vitamin D is not a true vitamin because unlike all the other vitamins it can be synthesized by your body from cholesterol and sunlight, which is not to say that we all have enough of it. When taking supplements we usually ingest Vitamin D2 or D3. The amount of dynamic Vitamin D that is available to you for bone synthesis and strength is determined by measuring your blood level of 25-OH (hydroxy) Vitamin D, and then taking Vitamin D supplements if your 25-OH level is low. With regard to sunlight, the latest studies indicate that after age 35 it is too late to reduce your risk of skin cancer by reducing the amount of UV sunlight that strikes your skin, and the majority of the damage has already been done by age 18.
It has never been shown that once you have a normal level of Vitamin D in your body that taking additional Vitamin D as a supplement has any positive effect. There is a meta-analysis showing that taking 800 IU of vitamin D was "somewhat favorable in preventing hip fracture", but "somewhat favorable" is a very imprecise scientific statement. In addition, I have shown elsewhere that all meta-analyses have inherent statistical weaknesses, and should only be used to generate a hypothesis which then should be tested by a properly constructed double-blind clinical study.
There are correlations of low levels of vitamin D with certain medical findings in addition to osteoporosis, but it has never been shown that taking vitamin D prevents or reverses these conditions. Some of these conditions are Alzheimer's Disease, immune response, and pre-eclampsia. Once again I must remind my readers that correlation is not causation, and that moving the arrow over the elevator door in the lobby of a building does not move the elevator.
You should all be made aware that Vitamin D is similar to Vitamin A and vitamin E in that it is fat-soluble and hence stored in your liver. Unlike the B vitamins or Vitamin C , it is not immediately excreted by your kidneys if ingested to excess, but rather the excess is stored in your liver. In fact so much Vitamin A and D can be stored in the liver of an animal that Eskimos have died from ingesting the liver of polar bears that they have killed. And we know from separate clinical studies that hypervitaminosis A can harm you, and that excess dietary supplements of Vitamin E can increase your risk of having a heart attack. So far the only demonstrated damage from prolonged ingestion of excessive amounts of Vitamin D is band keratopathy, or deposits in your cornea.
Vitamin D is needed, along with calcium and phosphorous, to form bones that are not thin and subject to fracture (osteoporosis) and that do not bend under the normal load of supporting the body (rickets). The process of normal bone formation is regulated by parathyroid hormone, which is secreted by four glands situated in your thyroid gland, usually two on each side. Vitamin D is not a true vitamin because unlike all the other vitamins it can be synthesized by your body from cholesterol and sunlight, which is not to say that we all have enough of it. When taking supplements we usually ingest Vitamin D2 or D3. The amount of dynamic Vitamin D that is available to you for bone synthesis and strength is determined by measuring your blood level of 25-OH (hydroxy) Vitamin D, and then taking Vitamin D supplements if your 25-OH level is low. With regard to sunlight, the latest studies indicate that after age 35 it is too late to reduce your risk of skin cancer by reducing the amount of UV sunlight that strikes your skin, and the majority of the damage has already been done by age 18.
It has never been shown that once you have a normal level of Vitamin D in your body that taking additional Vitamin D as a supplement has any positive effect. There is a meta-analysis showing that taking 800 IU of vitamin D was "somewhat favorable in preventing hip fracture", but "somewhat favorable" is a very imprecise scientific statement. In addition, I have shown elsewhere that all meta-analyses have inherent statistical weaknesses, and should only be used to generate a hypothesis which then should be tested by a properly constructed double-blind clinical study.
There are correlations of low levels of vitamin D with certain medical findings in addition to osteoporosis, but it has never been shown that taking vitamin D prevents or reverses these conditions. Some of these conditions are Alzheimer's Disease, immune response, and pre-eclampsia. Once again I must remind my readers that correlation is not causation, and that moving the arrow over the elevator door in the lobby of a building does not move the elevator.
Friday, July 13, 2012
How to Make Primary Care Financially Rewarding
I have noticed with deepening regret the diminishing numbers of medical students who choose to go into internal medicine and become providers of primary care. The problem is that the insurers reward doctors for doing, and not for thinking and diagnosing. This may be in part because thinking cannot be measured, but a biopsy is proof that the doctor did something. Now that many students graduate with massive load debts, it is even less financially attractive to go into primary care. And for those who are concerned, as they should be, with their quality of life, the hours required to make a living from a primary care practice seem expecially onerous.
There is something wrong with the financial reward system for physicians when the fee Medicare pays me for a rigid sigmoidoscopy, which takes 5 minutes to do and is easy to learn, is 3 times the fee they pay me for 15 contact minutes with the patient during which I diagnose and examine and apply my skill and art that is the product of 7 years of study and practice.
OTOH, dermatologists have a very nice and lucrative life, so much so that it is now the most competitive residency, with some programs looking back at the students' MCAT scores to help them pick future residents. This leads me to my plan to increase the income of primary care physicians. I was led to this in part by the many ads and faxes I get offering to train me in Botox injections and other dermatological procedures.
All fourth year medical students should have a mandatory month of dermatology. In the morning they would go to dermatology clinic. In the afternoon, they would be taught how to do simple skin and lesion biopsies, to inject Botox and Restalen, and to do other uncapped dermatology/plastic surgery procedures. Then when they open their practice of internal medicine, they could set aside each Friday for dermatological procedures. They would probably make as much in that one day as they did the rest of the week. They even have the most powerful selling line in the world: "I don't think that bump is cancerous, but let's biopsy it to make sure". In this manner they could easily double their incomes and afford to practice internal medicine.
There is something wrong with the financial reward system for physicians when the fee Medicare pays me for a rigid sigmoidoscopy, which takes 5 minutes to do and is easy to learn, is 3 times the fee they pay me for 15 contact minutes with the patient during which I diagnose and examine and apply my skill and art that is the product of 7 years of study and practice.
OTOH, dermatologists have a very nice and lucrative life, so much so that it is now the most competitive residency, with some programs looking back at the students' MCAT scores to help them pick future residents. This leads me to my plan to increase the income of primary care physicians. I was led to this in part by the many ads and faxes I get offering to train me in Botox injections and other dermatological procedures.
All fourth year medical students should have a mandatory month of dermatology. In the morning they would go to dermatology clinic. In the afternoon, they would be taught how to do simple skin and lesion biopsies, to inject Botox and Restalen, and to do other uncapped dermatology/plastic surgery procedures. Then when they open their practice of internal medicine, they could set aside each Friday for dermatological procedures. They would probably make as much in that one day as they did the rest of the week. They even have the most powerful selling line in the world: "I don't think that bump is cancerous, but let's biopsy it to make sure". In this manner they could easily double their incomes and afford to practice internal medicine.
Thursday, July 12, 2012
Does Azithromycin (Zithromax) cause Cardiac Deaths?
I was asked to address this subject by one of my more literate physician readers. I would like to remind everyone again that correlation does not equal causation. In particular, if patients with disease B have ingested A more often than those without disease B, we now have a hypothesis. The next scientific step would be to select a random group of matched individuals, have half of them ingest A, and then observe if they developed disease B in statistical excess of those who did not ingest A. It is extremely unlikely that such a clinical study would ever be undertaken. OTOH we have several retrospective studies which suggested that patients who ingested C had disease D less frequently, and then a forward, prospective, single-blind study was done to see if ingesting C prevented or reduced the incidence of disease D.
As a concrete example, several retrospective studies seemed to indicate that women with a low fat diet had a lower incidence of both breast and colon cancer. A five-year prospective study was then done, limiting women in the study group to a diet containing no more than 15% of its calories from fat. No decrease in the incidence of either cancer was noted. The organizers of the study therefore concluded that there was no evidence that a low-fat diet prevented colon or breast cancer. At the same time, the proponents of the benefits of a low-fat diet claimed that the % of fat in the diet should have been 5%, not 15%, while simultaneously admitting that such a diet was almost impossible to achieve in practice.
Now as to the case at hand. It was well known that macrolide antibiotics can lengthen the QT interval (on an electrocardiogram). It is also known that an electric cardiac phenomenon known as "R on T" can trigger ventricular tachycardia and thereby lead to sudden (cardiac) death. If the QT interval is increased, then there is a longer (by milliseconds) time interval in a cardiac cycle during which the "R on T" phenomenon can occur. In theory, therefore, any drug which lengthens the QT interval could pre-dispose the patient to sudden death. An increased incidence of ventricular tachycardia has been demonstrated in patients taking certain cardiac drugs that lengthen the QT interval, and such drugs are required to carry a "black box" warning because of this. Tricyclic antidepressants can also cause an increase in the QT interval, but usually the increase is not large enough to require a discontinuation of the drug.
An article was published recently in the New England Journal of Medicine (2012;366(20):1881-1890). It examined retrospectively the rate of cardiovascular (i.e. sudden) death of patients prescribed a five-day course of azithromycin (Zithromax)(Z-Pak) with those either taking no drug at all or taking amoxicillin, a different antibiotic. They found an excess of sudden death (called "cardiovascular deaths") in those taking azithromycin. The precise numbers were an additional 47 cardiovascular-related deaths per 1,000,000 courses of azithromycin in the patient population, and a further increase to 247 deaths per 1,000,000 in those at elevated risk for cardiovascular "adverse events".
This antibiotic and others of the macrolide class will now have an FDA-mandated warning. Again, this is a retrospective study, not a prospective one. I am just concerned that the study was of Medicaid patients, which means that they received generic Zithromax (i.e. azithromycin) and we have no way of knowing whether or not the brand name formulation is equally dangerous. If the result is a class effect, which it seems to be, then it should be equally dangerous, but no one knows for sure. I may or may not be splitting hairs here, and we will never find out.
As a concrete example, several retrospective studies seemed to indicate that women with a low fat diet had a lower incidence of both breast and colon cancer. A five-year prospective study was then done, limiting women in the study group to a diet containing no more than 15% of its calories from fat. No decrease in the incidence of either cancer was noted. The organizers of the study therefore concluded that there was no evidence that a low-fat diet prevented colon or breast cancer. At the same time, the proponents of the benefits of a low-fat diet claimed that the % of fat in the diet should have been 5%, not 15%, while simultaneously admitting that such a diet was almost impossible to achieve in practice.
Now as to the case at hand. It was well known that macrolide antibiotics can lengthen the QT interval (on an electrocardiogram). It is also known that an electric cardiac phenomenon known as "R on T" can trigger ventricular tachycardia and thereby lead to sudden (cardiac) death. If the QT interval is increased, then there is a longer (by milliseconds) time interval in a cardiac cycle during which the "R on T" phenomenon can occur. In theory, therefore, any drug which lengthens the QT interval could pre-dispose the patient to sudden death. An increased incidence of ventricular tachycardia has been demonstrated in patients taking certain cardiac drugs that lengthen the QT interval, and such drugs are required to carry a "black box" warning because of this. Tricyclic antidepressants can also cause an increase in the QT interval, but usually the increase is not large enough to require a discontinuation of the drug.
An article was published recently in the New England Journal of Medicine (2012;366(20):1881-1890). It examined retrospectively the rate of cardiovascular (i.e. sudden) death of patients prescribed a five-day course of azithromycin (Zithromax)(Z-Pak) with those either taking no drug at all or taking amoxicillin, a different antibiotic. They found an excess of sudden death (called "cardiovascular deaths") in those taking azithromycin. The precise numbers were an additional 47 cardiovascular-related deaths per 1,000,000 courses of azithromycin in the patient population, and a further increase to 247 deaths per 1,000,000 in those at elevated risk for cardiovascular "adverse events".
This antibiotic and others of the macrolide class will now have an FDA-mandated warning. Again, this is a retrospective study, not a prospective one. I am just concerned that the study was of Medicaid patients, which means that they received generic Zithromax (i.e. azithromycin) and we have no way of knowing whether or not the brand name formulation is equally dangerous. If the result is a class effect, which it seems to be, then it should be equally dangerous, but no one knows for sure. I may or may not be splitting hairs here, and we will never find out.
Monday, July 9, 2012
How to be a Healthier Patient
What can the individual do to extend his/her life? I am not going to talk about the obvious suggestions such as "lose weight", "get more exercise", "stop smoking", etc. Rather, I wish to consider simple modifications of habits that do not involve a life-long commitment, but rather are situational responses.
1) Be sure to finish the entire bottle of medicine. Too many patients stop talking the medicine, especially antibiotics, when they feel better. The problem with this is that the first seven days of a ten day course of penicillin may have only reduced the bacterial load to a level that you do not notice, but there are still enough left to "become fruitful and multiply" and make you sick again.
2) Never ignore blood in the stool. Too many patients ignore it until it goes away, and then never mention it to the doctor unless specifically asked about it (and sometimes not even then).
3) Tell the doctor all the drugs that you ingest, including vitamins and other over-the-counter products. There may have been a recent article in a medical journal pertaining to your supplement. For instance, there have been at least two published clinical studies demonstrating that taking vitamin E supplements increases your chance of having a heart attack. In this vein ( no pun intended) if you are taking a nutritional supplement, you should bring in to the doctor a list of all the compounds in the supplement.
4) Doctors are not opposed to alternative medicine per se, but to us "alternative" is another term for "not clinically proven to help", which is not to say that you are not benefiting from your particular treatment. And we do want to know about any such treatments you are undergoing, because it can impact on your overall health. We are are interested in all your health provider contacts: acupuncture, chiropractor, nutritionalist, yoga instructor, pilates, tai chi, biofeedback,-----.
5) Please also tell us about any illegal drugs you are using, not the least because they may interact negatively with a medical condition you have or with a prescribed or OTC drug you are taking.
6) Never stop or decrease a prescribed drug you are taking without notifying your doctor. Some drugs can cause rebound problems: abruptly stopping some anti-hypertensive medications has caused a rebound upsurge of blood pressure and a stroke. If you reduce an asthmatic drug too rapidly and get an asthma attack, the old inhaler may not be able to be inhaled to the proper depth in your lungs (because the resistance to the flow of air in your lungs varies inversely as the fourth power of the radius of the bronchioles). If you reduce an anti-depressant drug too rapidly you may need an even higher dose of the anti-depressant to control a recurrence.
7) Almost every patient has at one time or another tried a friend's or relative's sleeping pill or tranquilizer. Please tell your doctor, because whether the borrowed medicine worked or did not work is useful information for the doctor to know. (BTW, borrowing someone else's controlled medicine is probably the most commonly committed drug-related felony in the US, although few people think of it as such.)
8) At your annual physical, if the doctor does not ask, please tell him/her about any sources of emotional stress, especially if it involves your relationship with your spouse or SO, your parents, your children, your siblings, or your boss. Unresolved stress can lower your pain threshold as well as contribute to insomnia and depression. It is easier for the doctor than for you to see a possible solution to your problem , because your physician is thinking "outside the box" of your relationships.
9) The internet is full of truths, half-truths and lies. I generally tell my patients that it is OK to look up their disease, but not their symptoms. Almost every symptom is listed as a possible symptom of cancer, AIDS, Alzheimer's Disease, or multiple sclerosis, and reading about it will cause you to worry needlessly. The mind can imagine and worry in unbelievable amounts. Most medical students, during their second-year course in pathology, imagine that they have at least one of the diseases that they are studying.
10) If you are thinking about leaving your internist/gynecologist/dentist/..... but are hesitating to do so because you don't want to hurt his/her feelings, or the doctor is a relative, or a close friend, please leave anyway. It is your body, and the doctor should feel that it is a privilege to treat you. And if the doctor takes it the wrong way or gets angry, the doctor's ego is too big.
1) Be sure to finish the entire bottle of medicine. Too many patients stop talking the medicine, especially antibiotics, when they feel better. The problem with this is that the first seven days of a ten day course of penicillin may have only reduced the bacterial load to a level that you do not notice, but there are still enough left to "become fruitful and multiply" and make you sick again.
2) Never ignore blood in the stool. Too many patients ignore it until it goes away, and then never mention it to the doctor unless specifically asked about it (and sometimes not even then).
3) Tell the doctor all the drugs that you ingest, including vitamins and other over-the-counter products. There may have been a recent article in a medical journal pertaining to your supplement. For instance, there have been at least two published clinical studies demonstrating that taking vitamin E supplements increases your chance of having a heart attack. In this vein ( no pun intended) if you are taking a nutritional supplement, you should bring in to the doctor a list of all the compounds in the supplement.
4) Doctors are not opposed to alternative medicine per se, but to us "alternative" is another term for "not clinically proven to help", which is not to say that you are not benefiting from your particular treatment. And we do want to know about any such treatments you are undergoing, because it can impact on your overall health. We are are interested in all your health provider contacts: acupuncture, chiropractor, nutritionalist, yoga instructor, pilates, tai chi, biofeedback,-----.
5) Please also tell us about any illegal drugs you are using, not the least because they may interact negatively with a medical condition you have or with a prescribed or OTC drug you are taking.
6) Never stop or decrease a prescribed drug you are taking without notifying your doctor. Some drugs can cause rebound problems: abruptly stopping some anti-hypertensive medications has caused a rebound upsurge of blood pressure and a stroke. If you reduce an asthmatic drug too rapidly and get an asthma attack, the old inhaler may not be able to be inhaled to the proper depth in your lungs (because the resistance to the flow of air in your lungs varies inversely as the fourth power of the radius of the bronchioles). If you reduce an anti-depressant drug too rapidly you may need an even higher dose of the anti-depressant to control a recurrence.
7) Almost every patient has at one time or another tried a friend's or relative's sleeping pill or tranquilizer. Please tell your doctor, because whether the borrowed medicine worked or did not work is useful information for the doctor to know. (BTW, borrowing someone else's controlled medicine is probably the most commonly committed drug-related felony in the US, although few people think of it as such.)
8) At your annual physical, if the doctor does not ask, please tell him/her about any sources of emotional stress, especially if it involves your relationship with your spouse or SO, your parents, your children, your siblings, or your boss. Unresolved stress can lower your pain threshold as well as contribute to insomnia and depression. It is easier for the doctor than for you to see a possible solution to your problem , because your physician is thinking "outside the box" of your relationships.
9) The internet is full of truths, half-truths and lies. I generally tell my patients that it is OK to look up their disease, but not their symptoms. Almost every symptom is listed as a possible symptom of cancer, AIDS, Alzheimer's Disease, or multiple sclerosis, and reading about it will cause you to worry needlessly. The mind can imagine and worry in unbelievable amounts. Most medical students, during their second-year course in pathology, imagine that they have at least one of the diseases that they are studying.
10) If you are thinking about leaving your internist/gynecologist/dentist/..... but are hesitating to do so because you don't want to hurt his/her feelings, or the doctor is a relative, or a close friend, please leave anyway. It is your body, and the doctor should feel that it is a privilege to treat you. And if the doctor takes it the wrong way or gets angry, the doctor's ego is too big.
Sunday, June 24, 2012
Medical Screening Tests
In previous blogs I have discussed the rationale (or lack thereof) for certain tests, for certain questions in the medical history, and for the annual physical exam. Here I wish to discuss a more difficult question: the reason for performing certain screening tests. Again, let me emphasize that I am only talking about how a given screening test benefits the individual, and not how performing the test on the individual would benefit society. Whether or not an individual patient should submit to (and possibly pay for) a test that the doctor knows would only benefit society and not the patient is an interesting philosophical and ethical question, but that discussion is outside the scope of this blog. Needless to say the question of cost-effectiveness will not enter into my discussion, since if I am restricting myself to the direct benefit to the patient, the ultimate cost to society should be outside my purview. For the sake of this discussion, I will also assume that the test is 100 per cent accurate, with no false positives or negatives. I realize that this assumption is similar to assuming a straight line has no width, but the minute we admit the existence of errors in screening tests, the discussion has to include statistical probabilities as well as the incidence of the disease being screened for, and I am trying to keep this presentation as uncluttered as possible. I am also deliberately omitting any discussion of the optimum interval between tests, since there is virtually no hard data on this point for any test.
The problem, of course, with this minimal set of assumptions, is that we now have a reason for doing any test for which there is a treatment that can avert morbidity or death. A chest Xray could show unsuspected tuberculosis, a blood test could show unsuspected mercury poisoning, and an EKG could show a regular rhythm with unsuspected 2:1 block. Again, we are not interested in the probabilities of these diseases, but only with finding them. And of course if you asked the patient if he/she wanted to be tested for TB or elevated Hg+ or a cardiac arrhythmia, the answer would be "yes" in all instances. And if you as the patient's doctor knew in advance that a certain test would demonstrate a treatable condition, you would be morally and legally wrong not to order the test. So how do doctors decide which tests to do or not to do?
Unfortunately for the purist, this is where statistical probabilities and the doctor's diagnostic acumen and level of disease suspicion enter. Should every patient dwelling in the northeastern United States or certain other geographical areas have a western blot test for Lyme disease and babesiosis? Should every sexually active patient be tested for syphilis and HIV? Should every woman of child-bearing age receive a blood test for pregnancy before every Xray? Since at autopsy 10% of males at age 40 have coronary artery disease should every male have a stress-thallium at this age? Should everyone have a flexible sigmoidoscopy (which requires virtually no cleanout, unlike a colonoscopy) at age 30 to look for colon cancer? Shouldn't everyone have a skin test for tuberculosis? Shouldn't everyone receive an echocardiogram to look for IHSS and an abdominal USG to look for an abdominal aortic aneurysm?
After the tests are done, we then have methodological questions: At what level of fasting glucose should we label a patient as "pre-diabetic"? At what level of fasting glucose should we start pharmacological treatment, and what glucose level should be our goal? Since the risk of stroke and heart disease increases monotonically with systolic blood pressure, at what number should we start to treat blood pressure, and to what number do we wish to reduce it? To what number should the cholesterol be lowered? If we start to treat a patient, how often should the patient be retested? When a government-sponsored panel of doctors makes a health recommendation, why aren't we told the vote? (I am much more confident in following a 19-1 vote than a 12-8 vote.) And why aren't we told the arguments of the doctors who disagreed with the public health recommendation the way we are when the FDA recommends approval of a drug? And do the doctors who voted against the recommendation of the majority of the panel change the way they practice medicine to conform to the recommendation of the panel, even if they think the panel is wrong?
I hope this blog serves in part to show that there is an art of judgment in medicine. In today's topic the judgment lies in deciding which tests to order and which not to order. There is also another art of judgment when the test results come back: how "abnormal" does a blood test or Xray have to be in order to influence the treatment plan of the physician?
The problem, of course, with this minimal set of assumptions, is that we now have a reason for doing any test for which there is a treatment that can avert morbidity or death. A chest Xray could show unsuspected tuberculosis, a blood test could show unsuspected mercury poisoning, and an EKG could show a regular rhythm with unsuspected 2:1 block. Again, we are not interested in the probabilities of these diseases, but only with finding them. And of course if you asked the patient if he/she wanted to be tested for TB or elevated Hg+ or a cardiac arrhythmia, the answer would be "yes" in all instances. And if you as the patient's doctor knew in advance that a certain test would demonstrate a treatable condition, you would be morally and legally wrong not to order the test. So how do doctors decide which tests to do or not to do?
Unfortunately for the purist, this is where statistical probabilities and the doctor's diagnostic acumen and level of disease suspicion enter. Should every patient dwelling in the northeastern United States or certain other geographical areas have a western blot test for Lyme disease and babesiosis? Should every sexually active patient be tested for syphilis and HIV? Should every woman of child-bearing age receive a blood test for pregnancy before every Xray? Since at autopsy 10% of males at age 40 have coronary artery disease should every male have a stress-thallium at this age? Should everyone have a flexible sigmoidoscopy (which requires virtually no cleanout, unlike a colonoscopy) at age 30 to look for colon cancer? Shouldn't everyone have a skin test for tuberculosis? Shouldn't everyone receive an echocardiogram to look for IHSS and an abdominal USG to look for an abdominal aortic aneurysm?
After the tests are done, we then have methodological questions: At what level of fasting glucose should we label a patient as "pre-diabetic"? At what level of fasting glucose should we start pharmacological treatment, and what glucose level should be our goal? Since the risk of stroke and heart disease increases monotonically with systolic blood pressure, at what number should we start to treat blood pressure, and to what number do we wish to reduce it? To what number should the cholesterol be lowered? If we start to treat a patient, how often should the patient be retested? When a government-sponsored panel of doctors makes a health recommendation, why aren't we told the vote? (I am much more confident in following a 19-1 vote than a 12-8 vote.) And why aren't we told the arguments of the doctors who disagreed with the public health recommendation the way we are when the FDA recommends approval of a drug? And do the doctors who voted against the recommendation of the majority of the panel change the way they practice medicine to conform to the recommendation of the panel, even if they think the panel is wrong?
I hope this blog serves in part to show that there is an art of judgment in medicine. In today's topic the judgment lies in deciding which tests to order and which not to order. There is also another art of judgment when the test results come back: how "abnormal" does a blood test or Xray have to be in order to influence the treatment plan of the physician?
Friday, June 8, 2012
The Annual Physical
There has been much written lately about the utility or non-utility of the annual physical exam and its associated tests. There have been articles in the New York Times, the Annals of Internal Medicine and the Journal of the American Medical Association, as well as statements by the National Institutes of Health, the American College of Physicians, the American Academy for Family Practice the Canadian Medical Society, and various other organizations. Since there has never been an overall consensus, the reading public is left confused and thrown back on its own resources and preconceptions.
Firstly, what do we mean when we say that an annual physical exam is "beneficial" to the patient? The answer to that question depends in part on who we ask, and in part on how we measure "beneficiality". Do we ask the opinion of the patient, the doctor, a medical organization, a patient organization, an insurance company, or the government? Is an annual physical exam and its associated tests beneficial if it saves the patient's life, or if it reduces future morbidity, or if as a result the patient functions with more physical and/or mental energy? And what of the sense of well-being that a patient feels when he/she is told that the results of the annual exam were perfectly normal? Do we discount that feeling because there is no way to measure and quantify it? Isn't there value in reassuring a patient that his/her aches and pains are not the symptoms of a serious disease? What if the meat of the annual exam lay in one question that the physician answered for the patient, or one medical misconception that the doctor cleared up and thereby enabled the patient to avoid a future medical problem?
In previous blogs I have listed questions that should be asked at the annual physical, and which tests I think are medically beneficial and which are not, along with my reasons for the tests. One could make a case that just making sure that the patient received an annual flu shot is enough reason for an annual physical. One could also make a case for measuring blood pressure, since there is plenty of clinical evidence that treating hypertension with a regime that includes a diuretic reduces the patient's risk of a cerebral stroke. There is also an argument for annual testing for infectious diseases that can be treated, such as tuberculosis, syphilis and AIDS. What of the benefit to society when I ask a patient if he/she has trouble reading street signs at night while driving, and then suggest seeing an ophthalmologist if the answer is "yes"? I gloss over the obvious comments a physician would make to the patient about losing weight, stopping smoking and getting more exercise (although a recent study showed that 10% of the patients who exercise damage their health by doing so, two studies published in Lancet showed that overweight people with a BMI between 26 and 29 had better odds of surviving a heart attack, and two European studies demonstrated that smokers have a reduced incidence of Parkinson's disease). And should I encourage teetotalers to have a daily glass of wine since every study shows that this nutritional intervention improves mortality?
One fact that is never mentioned in all the discussions of annual physicals is state law: in every state it is a violation of "good medical practice" for a doctor to renew a prescription if the patient has not been seen within the previous 12 months (and more frequently for DEA-controlled drugs, which includes sleeping pills and tranquilizers). By age 40 almost every patient is taking at least one prescription drug, and therefore needs to be seen annually. And for those only taking over-the-counter supplements, their regime should also be reviewed annually to keep them from consuming OTC drugs that might be harmful----e.g. we now know that daily doses of Vitamin E increases your risk for having a heart attack.
Firstly, what do we mean when we say that an annual physical exam is "beneficial" to the patient? The answer to that question depends in part on who we ask, and in part on how we measure "beneficiality". Do we ask the opinion of the patient, the doctor, a medical organization, a patient organization, an insurance company, or the government? Is an annual physical exam and its associated tests beneficial if it saves the patient's life, or if it reduces future morbidity, or if as a result the patient functions with more physical and/or mental energy? And what of the sense of well-being that a patient feels when he/she is told that the results of the annual exam were perfectly normal? Do we discount that feeling because there is no way to measure and quantify it? Isn't there value in reassuring a patient that his/her aches and pains are not the symptoms of a serious disease? What if the meat of the annual exam lay in one question that the physician answered for the patient, or one medical misconception that the doctor cleared up and thereby enabled the patient to avoid a future medical problem?
In previous blogs I have listed questions that should be asked at the annual physical, and which tests I think are medically beneficial and which are not, along with my reasons for the tests. One could make a case that just making sure that the patient received an annual flu shot is enough reason for an annual physical. One could also make a case for measuring blood pressure, since there is plenty of clinical evidence that treating hypertension with a regime that includes a diuretic reduces the patient's risk of a cerebral stroke. There is also an argument for annual testing for infectious diseases that can be treated, such as tuberculosis, syphilis and AIDS. What of the benefit to society when I ask a patient if he/she has trouble reading street signs at night while driving, and then suggest seeing an ophthalmologist if the answer is "yes"? I gloss over the obvious comments a physician would make to the patient about losing weight, stopping smoking and getting more exercise (although a recent study showed that 10% of the patients who exercise damage their health by doing so, two studies published in Lancet showed that overweight people with a BMI between 26 and 29 had better odds of surviving a heart attack, and two European studies demonstrated that smokers have a reduced incidence of Parkinson's disease). And should I encourage teetotalers to have a daily glass of wine since every study shows that this nutritional intervention improves mortality?
One fact that is never mentioned in all the discussions of annual physicals is state law: in every state it is a violation of "good medical practice" for a doctor to renew a prescription if the patient has not been seen within the previous 12 months (and more frequently for DEA-controlled drugs, which includes sleeping pills and tranquilizers). By age 40 almost every patient is taking at least one prescription drug, and therefore needs to be seen annually. And for those only taking over-the-counter supplements, their regime should also be reviewed annually to keep them from consuming OTC drugs that might be harmful----e.g. we now know that daily doses of Vitamin E increases your risk for having a heart attack.
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