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Archive for March, 2013

More shameless self-promotion that is, I hope, at least entertaining

Three weeks ago, I gave a talk to the National Capital Area Skeptics at the National Science Foundation in Arlington, VA. The topic was one near and dear to my heart, namely quackademic medicine.

I was informed the other day that the video had finally been posted. Unfortunately, there were some problems with the sound in a couple of places, which our intrepid NCAS video editor did his best to fix. Overall, however, the sound quality seems decent. The video even includes the Q&A session. In case you’re interested, the guy who asks the question about mercury in vaccines and autism is Paul Offit’s very own stalker Jake Crosby. I feel honored to think that Jake now apparently lumps me in the same category as Paul Offit, whom I admire greatly. Enjoy.

Posted in: Clinical Trials, Energy Medicine, Homeopathy, Medical Academia, Science and Medicine

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Behold the spin! What a new survey of placebo prescribing really tells us

One of the recurring topics here at SBM is the idea of the placebo: What it is, what it isn’t, and how it complicates our evaluation of the scientific evidence. One my earliest lessons after I started following this blog (I was a reader long before I was a writer) was that I didn’t understand placebos well enough to even describe them correctly. Importantly, there is no single “placebo effect”. They are “placebo effects”, a range of variables that can include natural variation in the condition being studied, psychological factors and subjective effects reported by patients, as well as observer bias by researchers studying a condition. All of these, when evaluated in clinical trials, produce non-specific background noise that needs to be removed from the analysis. Consequently, we compare between the active treatment and the placebo to determine if there are an incremental benefits, to which we apply statistical tests to determine the likelihood that the differences between the intervention and the placebo groups are real. Removed from the observational nature of the clinical trial, we can’t expect the observed “placebo effects” to persist, as they’re partially a consequence of the trial itself. A more detailed review of placebos is a post in and of itself, so I’ll refer you to resources that describe why placebo effects are plural, that placebo effects are subjective rather than objective and there is no persuasive evidence to suggest that placebo effects offer any health benefits. What’s most important is the understanding that placebo effects are a measurement artifact, not a therapeutic effect.

Placebo effects are regular topics within in SBM posts because an understanding of placebo effects is essential to evaluating the evidence supporting (so-called) complementary and alternative medicine, or CAM. As better quality research increasingly confirms that the effects from CAM are largely, if not completely, attributable to placebo effects, we’ve seen the promoters of CAM shifting tactics. No longer able to honestly claim that CAM has therapeutic effects, “treatments” such as acupuncture or homeopathy are increasingly promoted as strategies that”harness the power of placebo” without all the pesky costs or side effects of real medical interventions. But this is simply special pleading from purveyors and promoters. Unable to wish away the well-conducted trials that show them to be indistinguishable from placebos, they instead are spinning placebo effects as meaningful and worthy of pursuit – ideally with your favourite CAM therapy. Again, I’ll refer you to posts by David Gorski and Steven Novella who offer a more detailed description of how negative results can be spun to look positive. Because CAM’s effects are indistinguishable from placebo, we should not invest time and resources into pursuing them – we should instead focus on finding treatments that are demonstrably superior to placebo.

But what if physicians are already using placebos widely in practice? Setting aside the ethical issues for now, widespread placebo usage might suggest that physicians believe that placebos are effective treatments. And that’s the impression you may have had if you skimmed the medical headlines last week:

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Posted in: Clinical Trials, Epidemiology, Science and Medicine

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Evidence Thresholds

Defenders of science-based medicine are often confronted with the question (challenged, really): what would it take to convince you that “my sacred cow treatment” works? The challenge contains a thinly veiled accusation — no amount of evidence would convince you because you are a nasty skeptic.

There is a threshold of evidence that would convince me of just about anything, however. In fact, I have been convinced that many scientific claims are likely to be true — sufficiently convinced to act upon the conclusion that they are true. In medicine this means that I am convinced enough to use them as a basis for medical practice.

There are many functional differences between practitioners of SBM and those who accept claims and practices that we would consider to be pseudoscience or fraud, but I was recently struck by one particular such difference — where we set the threshold of evidence before accepting a claim.

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Posted in: Homeopathy, Science and Medicine

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What Does ND Mean?

Chronic Lyme disease almost certainly does not exist, but a growing number of doctors are diagnosing and treating it with long-term antibiotics and other remedies. They are known as LLMDs (“Lyme Literate” medical doctors). This subject has been covered repeatedly on Science-Based Medicine, here, here, here, here, and elsewhere.

I have a correspondent who joined a Yahoo group for Lyme disease (Northern VA Lyme). She shared with me a message to that group that listed the LLMDs in their area. On that list was Patricia Slusher, ND, CN (naturopath, certified nutritionist). Other messages confirmed that Slusher is treating patients for “chronic Lyme disease.” One message specifically described the treatments prescribed by Patricia Slusher:

For the first 3 weeks my Lyme protocol consist of taking 3 supplements from Percision [sic] Herbs, LLC; LYX, Spirex and Puricell and spending 30 minutes 2X a week getting a Quad Zapper treatment. After the 3 weeks, my test for Lyme was negative. But bartonella was still positive. She has changed my supplements to taking Drainage-tone and Amoeba-chord by energetix and 15 minutes 1x a week of the Quad Zapper to fight the bartonella. I have doing [sic] this protocol for approx. 3 weeks. Along with this protocol I am on several other homeopathic supplements to address some of my symptoms, swollen lymph nodes, nerve pain (feels like someone is stabbing me with an ice pick or bugs crawling on me), numbness, inflammation, low vitamin D, etc. Also, supplements to raise the functioning level of my adrenals and kidneys. [Note: the Quad Zapper is a version of one of the infamous (more…)

Posted in: Energy Medicine, Naturopathy

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Once more into the screening breach: The New York Times did not kill your patient

One of the more depressing things about getting much more interested in the debate over how we should screen for common cancers, particularly breast and prostate cancer, is my increasing realization of just how little physicians themselves understand about the complexities involved in weighing the value of such tests. It’s become increasingly apparent to me that most physicians believe that early detection is always good and that it always saves lives, having little or no conception of lead time or length bias. Sadly, just last week, I saw another example of just this phenomenon in the form of an article written by Dr. George Lombardi entitled My Patient, Killed By The New York Times. The depth of Dr. Lombardi’s misunderstanding of screening tests permeates the entire article, which begins with his recounting a story about a patient of his, whose death he blames on The New York Times. After describing the funeral of this 73-year-old man who died of prostate cancer, Dr. Lombardi then makes an accusation:

This one filled me with a special discomfort as I knew a secret: He didn’t have to die. I knew it and he had known it. Had he told?

About 5 years ago he had just retired and had a lot more time on his hands. He was a careful man, lived alone, considered himself well informed. He got into the habit of clipping articles on medical issues and either mailing them to me or bringing them in. They came from a variety of sources and were on a variety of topics. He wasn’t trying to show me up. He was genuinely curious. I kidded him that maybe he’d like to go to medical school in his retirement. ‘No’ he laughed, ‘I just like to be in the know.’

When he came in for his physical in 2008 he told me he’d agree to the DRE but not the PSA (his medical sophistication extended to the use of acronyms: DRE stands for digital rectal exam where I feel the prostate with my gloved finger for any abnormality and PSA for prostatic [sic] specific antigen which is a blood protein unique to the prostate and often elevated in prostate cancer). He had read that the use of PSA as a screening test was controversial. This was the year that the United States Preventive Services Task Force, a government panel that issues screening guidelines, recommended against routine PSA screens for older men. It was often a false positive (the PSA was elevated but there was no cancer), led to unnecessary biopsies, and besides most prostate cancers at his age were indolent and didn’t need to be treated. I countered that prostate cancer was the second leading cause of cancer deaths in men and that it was better to know than not to know. This way it would be our decision. The patient with his doctor deciding what was best. But no, he wanted to stick to his guns and since the DRE was normal no PSA blood test was sent.

After describing a conversation with the man’s daughter, who said, “My father was killed by The New York Times,” Dr. Lombardi then goes on to anecdotal evidence and a cherry-picked publication to support his view, quoting an oncologist who says he’s “seeing more men presenting with advanced prostate cancer” and then referring to a single paper in the current Annals of Internal Medicine about PSA screening. Before I look at the article and a recently published paper on screening mammography that made the news, I can’t help but point out that I (mostly) agree with Dr. Lombardi when he says:

Public health doctors, policy experts and journalists tend to look at the population as a whole. It is a better story if it is one story. It makes a better headline. Their statistics are people I sit across from everyday trying to figure out what the future holds. We each have our job to do.

The problem is, of course, that Dr. Lombardi takes that observation and draws the wrong conclusion, namely that his patient died because of lack of screening. He attacks a straw man, sidestepping the true argument, namely that evidence shows that PSA screening probably causes more harm than good for men at average risk of prostate cancer. Unfortunately, Dr. Lombardi obviously does not understand some very basic concepts behind cancer screening, nor does he apparently recognize that doctors who deal with the population-level data that we have regarding screening tests and try to apply them to individual patients are actually looking in a very systematic way about what the benefits of screening are to the individual patient. More on that later. In the meantime, although I wouldn’t go quite as far as Dr. John Schumann did in criticizing Dr. Lombardi, I do view his lament as a jumping off point to look at some recent data on screening for the two most common cancers, breast and prostate.

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Posted in: Cancer, Diagnostic tests & procedures, Politics and Regulation, Public Health, Science and the Media

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Comprehending the Incomprehensible

Medicine is impossible. Really. The amount of information that flows out the interwebs is amazing and the time to absorb it is comparatively tiny.

If you work, sleep and have a family, once those responsibilities are complete there is remarkably little time to keep up with the primary literature. I have made two of my hobbies (blogging and podcasting) dovetail with my professional need to keep up to date, but most health care providers lack the DSM-4 diagnoses to consistently keep up.

So we all rely on short cuts. People rely on me to put new infectious disease information into context and there are those I rely upon to help me understand information both in my specialty and in fields that are unrelated to ID.

Up and down the medical hierarchies we trust that others are doing their best to understand the too numerous to count aspects of medicine that no single person could ever comprehend.

If I want to know about the state of the art on the treatment of atypical mycobacterium or how best to treat Waldenströms or who knows the most about diagnosing sarcoid, there is always someone who can distill their expertise on a topic to the benefit of the patient and my knowledge.

Trusting others is the biggest shortcut we routinely take in medicine to wade through the Brogdignagian amounts of information that flood into medical practice. We have to trust other clinicians, the researchers and the journals that all the information is gathered and interpreted honestly and accurately. (more…)

Posted in: Basic Science

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At Your Own Risk

In 2011, Americans spent some $30 billion on dietary supplements. Yet, except for the industry itself and a few politicians and “health freedom” advocates, you’d be hard pressed to find anyone (who’s given it some thought) of the opinion that dietary supplement regulation is adequate. Three recent reports, two from the government and one from a newspaper, demonstrate why this near-universal conclusion is warranted.

Another government report on lax supplement regulation

Here’s how an October, 2012, Department of Health and Human Services Office of Inspector General’s (OIG) report described the FDA’s regulatory authority:

DSHEA [Dietary Supplement Health and Education Act] does not require manufacturers to submit dietary supplements to FDA for safety or approval prior to sale. As a result, FDA has no comprehensive list of dietary supplements on the market. Dietary supplement manufacturers must ensure that their products are safe, they have evidence to substantiate structure/function claims, and that product labels are truthful and not misleading.

In other words, the fox guards the henhouse.

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Posted in: Herbs & Supplements, Legal, Politics and Regulation

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Clinical Decision-Making Part III

In part I of this series I discussed clinical pathways – how clinicians approach problems and the role of diagnosis in this approach. In part II I discussed the thought processes involved in deciding which diagnostic tests are worth ordering.

In this post I will discuss some of the logical fallacies and heuristics that tend to bias and distort clinical reasoning. Many of these cognitive pitfalls apply to patients as well as clinicians.

Pattern recognition and data mining

Science, including the particular manifestation we like to call science-based medicine, is about using objective methods to determine which patterns in the world are really real, vs. those that just seem to be real. The dire need for scientific methodology partly results from the fact that humans have an overwhelming tendency to automatically sift through large amounts of data looking for patterns, and we are very good at detecting patterns, even those that are just random fluctuations in that data.

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Posted in: Science and Medicine

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Dr. Amen’s Love Affair with SPECT Scans

Daniel Amen loves SPECT scans (Single Photon Emission Computed Tomography). And well he should. They have brought him fame and fortune. They have rewarded him with a chain of Amen Clinics, a presence on PBS, lucrative speaking engagements, a $4.8 million mansion overlooking the Pacific Ocean, and a line of products including books, videos and diet supplements (“nutraceuticals”).  He grossed $20 million last year.   Amen is a psychiatrist who charges patients $3,500 to take pretty colored SPECT pictures of their brains as an aid to the diagnosis and treatment of conditions including brain trauma, attention-deficit hyperactivity disorder (ADHD), addictions, anxiety, depression, dementia, and obesity. He even does SPECT scans as a part of marriage counseling and for general brain health checkups.

SPECT imaging uses an injected radioisotope to measure blood flow in different areas of the brain. Amen is exposing patients to radiation and charging them big bucks because his personal experience has convinced him SPECT is useful. So far, he has failed to convince the rest of the scientific medical community.

Amen has just published an article in the journal Alternative Therapies entitled “It’s Time to Stop Flying Blind: How Not Looking at the Brain leads to Missed Diagnoses, Failed Treatments, and Dangerous Behaviors.”  It amounts to poorly-reasoned apologetics with false analogies, testimonials, and pretty pictures that don’t prove what he thinks they prove. (more…)

Posted in: Neuroscience/Mental Health

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