Diagnostic tests & procedures

Archive for Diagnostic tests & procedures

When science- and evidence-based guidelines conflict with patient wishes: What’s a doc to do?

Evidence-based medicine triad

There’s a misconception that I frequently hear about evidence-based medicine (EBM), which can equally apply to science-based medicine (SBM). Actually, there are several, but they are related. These misconceptions include the idea that EBM/SBM guidelines are a straightjacket, that they are “cookbook medicine,” and that EBM/SBM should be the be-all and end-all of how to practice clinical medicine. New readers might not be familiar with the difference between EBM and SBM, and here is not the place to explain the difference in detail because this post isn’t primarily about that difference. However, for interested readers, a fuller explanation can be found here, here, here, and here. The CliffsNote version is that EBM fetishizes the randomized clinical trial above all other forms of medical investigation, a system that makes sense if the treatments being tested in RCTs have a reasonably high prior probability of translating to human therapies based on basic science mechanisms, experimental evidence in cell culture, and animal experiments. Using Bayesian considerations, when the prior probability is very low (as is the case for, for example, homeopathy), there will be a lot of false positive trials. Such is how EBM was blindsided by the pseudoscience of “complementary and alternative medicine” (CAM) or, as it is called now, “integrative medicine.”

However, for purposes of this post, SBM and EBM can be considered more or less equivalent, because we are not going to be discussing CAM, but rather widely accepted treatment guidelines based on science, both basic and clinical trial science. I merely mention this difference for completeness and for new readers who might not be familiar with the topics routinely discussed here. For purposes of this post, I’m talking evidence-based guidelines from major medical societies. More specifically, I want to address the disconnect between what patients often want and what our current guidelines state. It’s not just patients either, but doctors; however, for purposes of this post I’m going to focus more on patients. It’s a topic I’ve addressed before, in particular when it comes to breast cancer, where I’ve discussed changes in the mammography screening guidelines and Choosing Wisely guidelines for breast cancer. There are many other examples that I haven’t discussed. (more…)

Posted in: Cancer, Diagnostic tests & procedures

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Genetic Testing: Does Knowing Risk of Disease Make a Difference?

Genetic variants may provide information you'd rather ignore

Genetic variants may provide information you’d rather ignore

The complete sequencing of the human genome by the Human Genome Project was a remarkable accomplishment and a cause for celebration. Several companies including 23andMe, Navigenics, and deCODE have capitalized on that scientific achievement by offering genomic testing directly to the public. They promise more than they can deliver, and consumers don’t understand the limitations of the test results. The subject has been covered in several SBM articles.

One of the expected benefits of genomic testing is that if people knew they were at high risk of a disease, they would take preventive steps to reduce their risk. That seems plausible; but a recent study, a systematic review in the BMJ (formerly the British Medical Journal) calls that assumption into question. It found that communicating DNA-based disease risk estimates did not increase risk-reducing health behaviors or motivation to engage in such behaviors.


Posted in: Diagnostic tests & procedures

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The ROCA Screening Test for Ovarian Cancer: Not Ready for Prime Time

Ovarian cancer

Ovarian cancer

Ovarian cancer is relatively rare but deadly. The lifetime risk of ovarian cancer is 1.5% compared to 12% for breast cancer, but it is the 5th most common cause of cancer death for women. Since the ovaries are hidden deep in the pelvis and the symptoms of ovarian cancer are non-specific, the cancer is often advanced by the time it is diagnosed and survival rates are low. Early detection by screening would be expected to improve outcomes. Two screening methods have been proposed: the cancer antigen CA-125 blood test, and pelvic ultrasound. The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO) found that screening with CA-125 and ultrasound did not reduce ovarian cancer mortality. The USPSTF recommends against screening for ovarian cancer because it does not reduce mortality and carries important potential harms from false positives and unnecessary surgeries.

Ovarian cancer screening is being re-considered in the light of a recent study, the UKCTOCS trial, published in The Lancet in December 2015. On the basis of that study, a test called ROCA is being offered directly to the public for $295. It’s important to understand what the study actually found, and why experts have questioned the wisdom of offering this test to the public at this time. (more…)

Posted in: Cancer, Diagnostic tests & procedures

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Is the Annual Physical Unnecessary?


I was approached by The Wall Street Journal to write an article for their Big Issues in Health Care debate series. The subject was “Is the annual physical unnecessary?” I was to take the “yes” side and an internist was to take the “no” side. I wrote the following article. The editor wrote me a couple of times with questions. The internist pointed out the value of preventive medicine, developing a personalized healthcare plan, and developing a meaningful doctor-patient relationship. I said I wholeheartedly agreed, but I thought those goals could be accomplished just as well (arguably even better) with a periodic health maintenance interview or consultation. I pointed out that the traditional “physical” exam with stethoscope, routine lab tests, etc. provides no further advantages and can be counterproductive, with false positive or harmless findings leading to unnecessary worry, further testing, and expense. I said there was nothing magical about the interval of a year. I don’t know what the optimum interval would be; that could be studied. I suspect it would vary with the patient’s age, medical conditions, risk factors, and other considerations, and might be left up to the judgment of patient and doctor deciding together.

Finally I got an e-mail with apologies, saying they had decided not to continue with the debate because the internist and I agreed on too many important details. While I understand that stirring up a fight is good for selling newspapers, I think it’s a much better thing when people on two sides of a debate reach an agreement. It reassures me that they are converging on the truth. So I thought it would be worthwhile to publish my article here on SBM. (more…)

Posted in: Commentary, Diagnostic tests & procedures

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Functional medicine: The ultimate misnomer in the world of integrative medicine

Functional Medicine practitioners like to make patients think that this diagram actually means something.

Functional Medicine practitioners like to make patients think that this diagram actually means something.

We at Science-Based Medicine often describe “integrative medicine” as integrating quackery with medicine (at least, I often do), because that’s what it in essence does. The reason, as I’ve described time and time again, is to put that quackery on equal footing (or at least apparently equal footing) with science- and evidence-based medicine, a goal that is close to being achieved. Originally known as quackery, the modalities now being “integrated” with medicine then became “complementary and alternative medicine” (CAM), a term that is still often used. But that wasn’t enough. The word “complementary” implies a subordinate position, in which the CAM is not the “real” medicine, the necessary medicine, but is just there as “icing on the cake.” The term “integrative medicine” eliminates that problem and facilitates a narrative in which integrative medicine is the “best of both worlds” (from the perspective of CAM practitioners and advocates). Integrative medicine has become a brand, a marketing term, disguised as a bogus specialty.

Of course, it’s fairly easy to identify much of the quackery that CAM practitioners and woo-friendly physicians have “integrated” itself into integrative medicine. A lot of it is based on prescientific ideas of how the human body and disease work (e.g., traditional Chinese medicine, especially acupuncture, for instance, which is based on a belief system that very much resembles the four humors in ancient “Western” or European medicine); on nonexistent body structures or functions (e.g., chiropractic and subluxations, reflexology and a link between areas on the palms of the hands and soles of the feet that “map” to organs; craniosacral therapy and “craniosacral rhythms”); or vitalism (e.g., homeopathy, “energy medicine,” such as reiki, therapeutic touch, and the like). Often there are completely pseudoscientific ideas whose quackiness is easy to explain to an educated layperson, like homeopathy.

Posted in: Critical Thinking, Diagnostic tests & procedures, Herbs & Supplements

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Regulating CAM Aussie Style

CAM proponents view National Health Interview Surveys recording the supposed popularity of CAM, an amorphous conflation of anything from conventional medical advice to mythical methods, as an invitation to unleash even more unproven remedies on the public. My interpretation is quite different. I see the same figures as proof that we are doing too little to protect the public from pseudoscience.

In fact, state and federal governments are acting as handmaidens to the CAM industry by legalizing practices and products that have insufficient proof of safety and efficacy and, in some cases, are so scientifically implausible that they can never meet that standard. The federal government keeps “integrative” medicine centers at major academic institutions and private foundations afloat with taxpayer money by funding research that has failed to improve public health or the treatment of disease, despite seemingly endless trials, because “more research is needed”.

As we shall see, Australia has a more effective regulatory system for dealing with CAM. And the advocacy group Friends of Science in Medicine (FSM), an organization with goals similar to our own Society for Science-Based Medicine, is keeping the government on its toes, investigating violations of the law on its own and reporting them. We in the US could learn something from their two recent successful campaigns attacking misleading health claims. (more…)

Posted in: Chiropractic, Diagnostic tests & procedures, Guidelines, Legal, Naturopathy, Politics and Regulation

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Carotid Artery Stenosis: Surgery, Stent, or Nonsurgical Stroke Prevention?

One treatment for carotid artery stenosis: stent placement

One treatment for carotid artery stenosis: stent placement

The carotid artery in the neck is a common site of atherosclerosis. As plaque builds up, it leaves less room for blood flow and can cause strokes through clotting or embolization. Carotid stenosis is defined as a greater than 70% narrowing of the lumen (the space through which the blood flows in an artery). It can cause symptoms, including transient ischemic attacks (TIAs) and minor strokes; but it is frequently asymptomatic. It can be treated with carotid endarterectomy (CEA) or carotid angioplasty and stenting (CAAS). There has been much discussion about which procedure is better and when it is better not to do either. (more…)

Posted in: Diagnostic tests & procedures, Surgical Procedures

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Lyme Testing

The little burrowing bacteria that bores into your pores to cause Lyme disease, EEEEEWWW!!!

The little burrowing bacteria that bores into your pores to cause Lyme disease, EEEEEWWW!!! Darkfield 400x microscopy image of the 10-25µm long Borrelia burgdorferi spirochaete which causes Lyme disease (1993). Provided by the CDC’s Public Health Image Library (PHIL #6631) via the Wikimedia Commons

I hate those oh hell moments. I was up way too late last night, but who can pass up the opportunity to see Patti Smith playing Horses (and more) for the 40th anniversary of the album. Only 44? Behind the Eagles? No way. I would nudge it up a few more spaces. Hard to believe I was 18 when that album came out. Horses is one of the few albums that made the transition from vinyl to CD. It was a tremendous show, and at 69 Patt performs with the energy and passion of a 29 year old. And she sure can spit. I had the evening off, so food and drinks at Swine until well past midnight. First time my wife and I closed a bar. I am too old for this.

But as I was blearily drinking my a.m. coffee on a dreary PDX morning, I opened the browser to SBM and there was a post by Jann. Oh hell. That means I have a post due tomorrow and I had lost track of the time over the holidays. I thought my next post was next Friday. Oh. Hell. So unlike most posts which I write over a week, this one was done in about 4 hours. And I am sure it will show.

How do you diagnose an infection?

Not always so simple. You always start with a history and, for infectious diseases, an exposure history is paramount. People get what they are exposed to, so you want to know travel, animals, diet, water, sex etc. If you have ridden a horse to have sex in an Indian lake while drinking raw milk (not really an unusual history in my practice; people do the darndest things) you have exposure risks for a variety of infections. If you have not left the Willamette Valley it is unlikely that the cause of the illness is malaria, although you always have to consider that the infection came to the patient rather than the other way around. (more…)

Posted in: Basic Science, Diagnostic tests & procedures, Lyme, Science and Medicine

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Legislative Alchemy 2015: Another losing season for CAM practitioners

One of the main, but perhaps underappreciated, reasons quackery thrives in the United States is that the states legalize it by licensing practitioners of pseudoscience as health care providers. These practitioners are placed under the regulatory jurisdiction of, well, themselves. I call the whole deplorable process Legislative Alchemy, and you can see all posts on the topic here. It gives practitioners an underserved imprimatur of state authority and leaves public protection from harmful practices to the oversight of those who are themselves engaging in the very same conduct. Each year, dozens of bills are brought before the state legislatures to establish initial licensure or, once that goal is achieved, scope of practice expansion.

Most attempts fail, but CAM practitioners are a dogged bunch, and they will come back each year until they get what they want. It took chiropractors about 60 years to become licensed in all 50 states. Acupuncturists are almost there. Naturopaths lag far behind, but are slowly gaining ground each year, even if it is only via practice expansion in states where they are already licensed. 2015 was a losing season for all, but not without advancement toward larger goals.


Posted in: Acupuncture, Chiropractic, Diagnostic tests & procedures, Herbs & Supplements, Homeopathy, Legal, Naturopathy, Politics and Regulation

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