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Archive for 2012

Anecdotes: Cheaper by the Dozen

A loan officer sets up a meeting with an aspiring entrepreneur to inform him that his application has been denied. “Mr Smith, we have reviewed your application and found a fatal flaw in your business plan. You say that you will be selling your donuts for 60 cents apiece. “Yes” says Mr. Smith, “that is significantly less than any other baker in town. This will give my business a significant competitive advantage!” The loan officer replies, “According to your budget, at peak efficiency the cost of supplies to make each donut is 75 cents, you will lose 15 cents on every donut you sell. A look of relief comes over Mr. Smith’s face as he realizes the loan officer’s misunderstanding. He leans in closer, and whispers to the loan officer “But don’t you see, I’ll make it up in volume.”

If you find this narrative at all amusing, it is likely because Mr. Smith is oblivious to what seems like an obvious flaw in his logic.

A similar error in logic is made by those who rely on anecdote and other intrinsically biased information to understand the natural world. If one anecdote is biased, a collection of 12 or 1000 anecdotes multiplies the bias, and will likely reinforces an errant conclusion. When it comes to bias, you can’t make it up in volume. Volume makes it worse!

Unfortunately human beings are intrinsically vulnerable to bias. In most day to day decisions, like choosing which brand of toothpaste to buy, or which route to drive to work, these biases are of little importance. In making critical decisions, like assessing the effectiveness of a new treatment for cancer, these biases may make the difference between life and death. The scientific method is defined by a system of practices that aim to minimize bias from the assessment of a problem.

Bias, in general, is tendency that prevents unpredjudiced consideration of a question (paraphrased from dictionary.com). Researchers describe sources of bias as systematic errors. A few words about random and systematic errors will make this description clearer.
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Posted in: Clinical Trials, Science and Medicine

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True Informed Consent Is Elusive

Most of us would agree that doctors should not treat patients without their consent, except in special cases like emergency care for an unconscious patient.  It’s not enough for doctors to ask “Is it OK with you if I do this?” They should get informed consent from patients who understand the facts, the odds of success, and the risk/benefit ratio of treatments. The ethical principle of autonomy requires that they accept or reject treatment based on a true understanding of their situation and on their personal philosophy. Numerous studies have suggested that patients are giving consent based on misconceptions. There is a failure of communication: doctors are not doing a good job of providing accurate information and/or patients are failing to process that information. I suspect it is a combination of both.

An article in The New England Journal of Medicine reports that while the great majority of patients with advanced lung cancer and colorectal cancer agree to chemotherapy, most of them have unreasonable expectations about its benefits. For some cancers chemotherapy can be curative, but for metastatic lung or colorectal cancer it can’t. For these patients, chemotherapy is only used to prolong life by a modest amount or to provide palliation of symptoms. Patients were asked questions like “After talking with your doctors about chemotherapy, how likely did you think it was that chemotherapy would… help you live longer, cure your cancer, or help you with problems you were having because of your cancer?” A whopping 69% of lung cancer patients and 81% of colorectal cancer patients believed it was likely to cure their cancer, and most of these thought it was very likely. (more…)

Posted in: Cancer, Medical Ethics, Pharmaceuticals

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Getting NCCAM’s money’s worth: Some results of NCCAM-funded studies of homeopathy

As hard as it is to believe, the Science-Based Medicine blog that you’re so eagerly reading is fast approaching its fifth anniversary of existence. The very first post here was a statement of purpose by Steve Novella on January 1, 2008, and my very first post was a somewhat rambling introduction that in retrospect is mildly embarrassing to me. It is what it is, however. The reason I mention this is because I want to take a trip down memory lane in order to follow up on one of my earliest posts for SBM, which was entitled The National Center for Complementary and Alternative Medicine (NCCAM): Your tax dollars hard at work. Specifically, I want to follow up on one specific study I mentioned that was funded by NCCAM.

Even though I not-so-humbly think that, even nearly five years later, my original post is worth reading in its entirety (weighing in at only 3,394 words, it’s even rather short—for me, at least), I’ll spare you that and cut straight to the chase, the better to discuss the study. It is a study of homeopathy. Yes, in contrast to the protestations of Dr. Josephine Briggs, the current director of NCCAM, that NCCAM doesn’t fund studies of such pure pseudoscience as homeopathy anymore (although she does apparently meet with homeopaths for “balance”), prior to Dr. Briggs’ tenure NCCAM actually did fund studies of the magic water with mystical memory known as homeopathy. Two grants in particular I singled out for scorn. The principal investigator for both grants was Iris Bell, who is faculty at Andrew Weil’s center of woo at the University of Arizona. The first was an R21 grant for a project entitled Polysomnography in homeopathic remedy effects (NIH grant 1 R21 AT000388).
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Posted in: Basic Science, Clinical Trials, Homeopathy

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Blonde Blood

Two scientists walk into a bar
The first one says “I’ll have some H2O.”
The second one says, “I’ll have some H2O too.”
Then he dies.

I have come to believe in my own version of The Secret.

The Secret describes the law of attraction as a natural law that determines the complete order of the universe and of our personal lives through the process of “like attracts like. The author claims that as we think and feel, a corresponding frequency is sent out into the universe that attracts back to us events and circumstances on that same frequency.

Obviously not true as I have yet to win Powerball. But a variant of the Secret is kind of creepy. As soon as I learn about a new concept, in medicine or life, I start to see it. All the time. Perhaps my learning a new concept causes it to spring forth like Athena. I would have said instantiate, but I got all sorts of grief when I used that word last time. For example, shortly after reading a review of infections in patients with Osler-Weber-Rendu,  I saw a case. Creepy. As I drive from hospital to hospital I listen to Audible books and it is equally creepy how often I see a word in my visual field that is identical to the word I am listening to. (more…)

Posted in: Science and Medicine

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CAM Docket: Functional Endocrinology

 

One of the signature abilities of CAM practitioners is the creation of new diagnostic methods and treatments which convincingly demonstrate they have only a superficial understanding of human physiology. Here at SBM, posts have addressed such sterling examples of this phenomenon as cranial sacral therapy, applied kinesiology and chiropractic neurology. Now we have a new one on the horizon: functional endocrinology.

I don’t know who thought up this idea, but a primary promoter appears to be a Colorado chiropractor, Brandon Credeur, a 2002 graduate of Parker Chiropractic College in Texas. In additional to operating the Functional Endocrinology Center of Colorado, in Denver (where he practices with his wife, Heather Credeur, D.C.), he sold (and may still be selling) practice-building courses on functional endocrinology to other chiropractors.

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Posted in: Science and Medicine

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Is There a Treatment for Tinnitus

There are several features of a symptom or illness that make it a convenient target for proponents of unconventional therapies. Subjective symptoms are more likely to be targeted than objective conditions – you don’t see many so-called “alternative” birth control treatments. Symptoms for which placebo effects alone are likely to produce the illusion of effectiveness are good targets for ineffective treatments. Symptoms that vary naturally over time also are good targets – patients are likely to seek treatment when their symptoms are maximal, which means spontaneous regression to the mean will provide an effective illusion of efficacy for any intervention.  Illnesses with a substantial psychological component (such as those that are worsened by emotional stress or that are emotional, such as anxiety) are likely to benefit from non-specific effects of the therapeutic interaction, rendering the treatment itself irrelevant.

Finally, any condition or symptom for which there is currently no effective treatment provides a market ripe for exploitation.

Tinnitus has many of these features. Tinnitus describes the subjective experience of spontaneous noise perceived in one or both ears, which can be a buzzing, hiss, tone, or ringing sound. The severity of the tinnitus, its loudness, can vary over time, but perhaps more importantly the degree to which the tinnitus is bothersome can vary considerably. The sound is distracting and can have a significant impact on quality of life. Those with tinnitus can ignore the sound at times (depending on its severity), can be distracted from the sound, and may even learn through cognitive therapy to become accustomed to it. Therefore we might expect that tinnitus is amenable to placebo effects.

Finally, there is no proven effective treatment for tinnitus, which means that those who suffer from tinnitus may be desperate for a treatment. Desperation is a commodity highly prized by snake-oil salesmen.

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Posted in: Neuroscience/Mental Health

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Fan Mail from an ASEA Supporter

We have an active comments section on our blog, but for some reason some people prefer not to comment there, but to send personal e-mails to authors when they disagree. Some of them make me laugh. Some of them make me despair. We can carry on our struggle better if we know what we are fighting; and in that spirit, I want to describe a recent e-mail exchange.

If an e-mail is filled with angry CAPITALS and abusive language, I know there is no point in responding. But I still get suckered in by the ones that start out sounding as if a productive dialog might be possible; unfortunately, discussions almost always degenerate. In this case, it started with a polite request for my opinion about a specific study. (more…)

Posted in: General, Herbs & Supplements

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“Moneyball,” the 2012 election, and science- and evidence-based medicine

Regular readers of my other blog probably know that I’m into more than just science, skepticism, and promoting science-based medicine (SBM). I’m also into science fiction, computers, and baseball, not to mention politics (at least more than average). That’s why our recent election, coming as it did hot on the heels of the World Series in which my beloved Detroit Tigers utterly choked got me to thinking. Actually, it was more than just that. It was also an article that appeared a couple of weeks before the election in the New England Journal of Medicine entitled Moneyball and Medicine, by Christopher J. Phillips, PhD, Jeremy A. Greene, MD, PhD, and Scott H. Podolsky, MD. In it, they compare what they call “evidence-based” baseball to “evidence-based medicine,” something that is not as far-fetched as one might think.

“Moneyball,” as baseball fans know, refers to a book by Michael Lewis entitled Moneyball: The Art of Winning an Unfair Game. Published in 2003, Moneyball is the story of the Oakland Athletics and their manager Billy Beane and how the A’s managed to field a competitive team even though the organization was—shall we say?—”revenue challenged” compared to big market teams like the New York Yankees. The central premise of the book was that that the collective wisdom of baseball leaders, such as managers, coaches, scouts, owners, and general managers, was flawed and too subjective. Using rigorous statistical analysis, the A’s front office determined various metrics that were better predictors of offensive success than previously used indicators. For example, conventional wisdom at the time valued stolen bases, runs batted in, and batting average, but the A’s determined that on-base percentage and slugging percentage were better predictors, and cheaper to obtain on the free market, to boot. As a result, the 2002 Athletics, with a payroll of $41 million (the third lowest in baseball), were able to compete in the market against teams like the Yankees, which had a payroll of $125 million. The book also discussed the A’s farm system and how it determined which players were more likely to develop into solid major league players, as well as the history of sabermetric analysis, a term coined by one of its pioneers Bill James after SABR, the Society for American Baseball Research. Sabermetrics is basically concerned with determining the value of a player or team in current or past seasons and with predicting the value of a player or team in the future.
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Posted in: Clinical Trials, Politics and Regulation, Science and Medicine, Science and the Media

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Eat To Save Your Life: Another Half-True Diet Book

I am hesitant to review diet books because they are so often a tangled mess of fact and fiction. Teasing out their truth from falsehood is about as exhausting as delousing a long-haired elementary school student. However, after being approached by the authors’ PR agency with the promise of a book that contains science-based nutrition information I decided to agree to the review. This is how the book was described to me in an email:

In their provocative new book, Eat to Save Your Life, best-selling authors Dr. Jerre Paquette and Gloria Askew, RRN, sort through the piles of information and misinformation about nutrition to reveal the true connection between food and health. Fed up with the advertising hype and conflicting nutritional advice, the duo provides common sense explanations for consumers everywhere who are looking to make smart nutritional choices.

Unfortunately, I was sold (quite predictably) a bill of goods. And rather than ignore the book and simply not do a review, I figured that maybe a negative review would reduce the number of incoming PR requests for future tomes of pseudoscience. In the end, I’ll probably just become the focus of personal attacks by dedicated proponents of various snake oils. 

That being said, I thought it might be somewhat instructive to remind SBM readers of certain basic “warning signs of pseudoscience” that I accidentally overlooked in agreeing to review the book. For a more complete review of similar “signs” I highly recommend Dr. David Gorski’s 2007 classic, humorous take on predictable arguments and behaviors of alternative medicine proponents (written in the style of comedian Jeff Foxworthy).  As for me, I tend to think of much of the world of integrative medicine as a militant group of bakers eager to add odd, inert and occasionally toxic substances to cake recipes. 
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Posted in: Book & movie reviews, Nutrition

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It’s time for true transparency of clinical trials data

What makes a health professional science-based? We advocate for evaluations of treatments, and treatment decisions, based on the best research methods. We compile evidence based on fair trials that minimize the risks of bias. And, importantly, we consider this evidence in the context of the plausibility of the treatment. The fact is, it’s actually not that hard to get a positive result in a trial, especially when it’s sloppily done or biased.  And there are many ways to design a trial to demonstrate positive results in some subgroup, as Kimball Atwood pointed out earlier this week. And even when a trial is well done, there remains the risk of error simply due to chance alone. So to sort out true treatment effects, from fake effects, two key steps are helpful in reviewing the evidence.

1. Take prior probability into account when assessing data. While a detailed explanation of Bayes Theorem could take several posts, consider prior probability this way: Any test has flaws and limitations. Tests give probabilities based on the test method itself, not on what is being tested. Consequently, in order to evaluate the probability of “x” given a test result, we must incorporate the pre-test probability of “x”. Bayesian analysis uses any existing data, plus the data collected in the test, to give a prediction that factors in prior probabilities. It’s part of the reason why most published research findings are false.

2. Use systematic reviews to evaluate all the evidence. The best way to answer a specific clinical question is to collect all the potentially relevant information in a structured way, consider its quality, analyze it according to predetermined criteria, and then draw conclusions. A systematic review reduces the risk of cherry picking and author bias, compared to non-systematic data-collection or general literature reviews of evidence. A well-conducted systematic review will give us an answer based on the totality of evidence available, and is the best possible answer for a given question.

These two steps are critically important, and so have been discussed repeatedly by the contributors to this blog. What is obvious, but perhaps not as well understood, is how our reviews can still be significantly flawed, despite best efforts. In order for our evaluation to accurately consider prior probability, and to be systematic, we need all the evidence. Unfortunately, that’s not always possible if clinical trials remains unpublished or are otherwise inaccessible. There is good evidence to show that negative studies are less likely to be published than positive studies. Sometimes called the “file drawer” effect, it’s not solely the fault of investigators, as journals seeking positive results may decline to publish negative studies. But unless these studies are found, systematic reviews are more likely to miss negative data, which means there’s the risk of bias in favor of an intervention. How bad is the problem? We really have no complete way to know, for any particular clinical question, just how much is missing or buried. This is a problem that has confounded researchers and authors of systematic reviews for decades. (more…)

Posted in: Clinical Trials, Politics and Regulation

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