Oct 26 2010

Dr. Zilberberg Responds

Yesterday I wrote a post about criticism of SBM from Marya Zilberberg at Healthcare, etc. I framed the post by saying I enjoy the conversation afforded by blogs, but lamented that often critics of SBM stoop to ad hominems rather than engage in substantive debate. Today Dr. Zilberberg responds and has significantly modified her tone, to her credit. (She was simultaneously responding to Orac’s analysis of her posts as well.)

The Tone Thing

I will address her main points below, but first my final thoughts on the “tone” thing. While she admits fault in setting the “confrontational tone,” I don’t think she quite gets what Orac and I were objecting to. I actually don’t mind a confrontational approach – as long as it is substantive (that’s the way science works – if you have a point to make, bring it on). We were objecting to her mischaracterizing our position and making ad hominem attacks in place of substantive criticism – essentially using the “arrogant” gambit with which we are all too familiar. Her readers obviously picked up on this, and piled one, accusing us of being bullies and thanking her for slapping us down. We objected to her logical fallacies, not her tone.

Interestingly Zilberberg’s initial response was dismissive, and she reiterated the charge of paternalism and arrogance, writing: “If the shoe fits?” At least now she seems to realize that if we are going to have a productive discussion, focusing on ad hominem attacks will be counterproductive.

Incidentally, having written about medicine for years I have definitely seen a strong pattern. When I criticize the logic and factual premises of another person’s argument I am frequently accused of being mean by people who then attack me personally. It seems many people do not understand the difference between a strong but substantive criticism and a personal attack. Zilberberg was falling into this category, but has significantly (if incompletely) backed off from that with her latest post.

One more minor point – “allopathic” is derogatory and does not apply to modern medicine (It was coined by Samuel Hahneman to refer to the poisons that passed for medicine in his time, and was definitely meant to be a criticism). I would suggest she drop this term rather than defend it.

Evidence in Medicine

Zilberberg then launches into a meaty discussion of what her position actually is. She observes that perhaps we are not that far off in our positions, which I think is true. There is a meaningful difference in spin – the final conclusions drawn from the analysis, but her analysis of the role of evidence in medicine is reasonable. But again, to clarify, Orac and I were not objecting to the point that evidence in medicine is messy and complex. We were objecting to the accusation that we do not understand this, and that we are promoting an overly simplistic and cheerleading approach to science in medicine. This left me with the impression that Zilberberg has not read deeply into the Science-Based Medicine website, or at least has failed to grasp what it is we are actually saying.

If she had she would have seen post after post in which SBM authors were pointing out all of the complexities and deficiencies of evidence in medicine that she and others might also point to. That is core to the point of SBM – evidence is complex. She might, in fact, have read my series of posts on evidence in medicine. We do spend a great deal of time pointing this out in the context of so-called CAM, because CAM proponents are the ones who most profoundly take a simplistic approach to the evidence. They engage in black-and-white thinking, display intolerance of ambiguity,  and frequently advocate for the reliance of very problematic low-grade evidence to support their claims. But we also consistently apply the same standards to surgery and the pharmaceutical industry, and anything “mainstream.’

Zilberberg reviews the relative roles of experimental evidence vs observational evidence. Her analysis is reasonable, but I think she overstates the utility of observational data a bit (and she admits to a fondness for this type of data). The bottom line is that each type of evidence (basic science, observational, and experimental – and even anecdotal) has its own strengths and weaknesses, and the best result comes from analyzing all kinds of scientific evidence and looking for a consensus of evidence. That is, in fact, OUR criticism of evidence-based medicine -over reliance on randomized controlled clinical trials and undervaluing other forms of scientific evidence. That is why we advocate for “science”-based medicine, and not just “evidence”-based medicine.

Each type of evidence, in fact, is abused. We criticize the inappropriate extrapolation from basic science to clinical claims, assuming causation from observational correlation, failure to realize the limits of clinical trials, and the use of pragmatic studies as if they were evidence for efficacy.

Zilberberg also clarifies her position by saying that she feels there is good scientific evidence for some of medicine, but it seems she differs from my position in how evidence-based modern medicine actually is.

We can argue endlessly about this question – how much of modern medicine is based upon solid evidence – each pointing to limited examples and essentially giving our bias. But there are some facts we can point to. Zilberberg writes:

While it is true that the oft-cited 5-20% number representing the proportion of medical treatments having solid evidence behind them is very likely outdated, the kind of evidence we are talking about is a different matter.

The “5-20% number” is not outdated – it’s a myth. Actually, I had previously heard 15% as the low end, but I guess that number keeps dropping. I wrote previously about this myth here. The 15% number was based upon an extremely small survey of primary care practices in the north of England – in 1961. That’s almost 50 years ago. The number was never very relevant, and now it’s a joke.

More recent surveys of medical practice come to very different numbers. Bob Imrie reviewed the published evidence:

Thus, published results show an average of 37.02% of interventions are supported by RCT (median = 38%). They show an average of 76% of interventions are supported by some form of compelling evidence (median = 78%).

Of course, where you draw the line for “supported by compelling evidence” will determine what the percentage figure is. But the bottom line is that the 15% figure is basically an urban legend, and “5%” is nothing short of propaganda. More reasonable estimates range much higher.

And – the point of EBM and SBM is that we can and should do better. We also need to do better in adhering to EBM guidelines where they exist, and in utilizing continuing medical education and other mechanisms of quality control to improve adherence to the evidence where it does exist.

The difference in spin is not subtle. We can look at the evidence and say – modern medicine has a culture of science, endeavors to be scientific, and basically the system works but the process is complex and messy and there are multiple ways in which we can do better. Meanwhile someone else can look at the same data and conclude – modern medicine is broken, it is based upon arrogance, authority, and greed, and we can just throw up our hands and conclude that any treatment is as likely to be of value as any other, no matter how silly it may seem scientifically.

My position is essentially the former. Zilberberg came off originally as being close to the latter (and judging by the comments, many readers took her position to be supportive of the latter), but now has clarified that she is somewhere in the middle.

CAM

Zilberberg also clarifies her position on CAM. She had previously written that she advocates a position of “equipoise” towards clinical claims. Even though she might not use certain modalities herself, she sees no basis to condemn the use of them by others. I characterized this position as political correctness gone wild – to the point of practical post-modernism. Now she writes:

My belief is that all modalities that may impact what happens to public’s health need to be evaluated for safety, not question. I think we both agree, since there is really no reason to think that something like homeopathy has anything that can help, by the same token we do not believe that it have anything that can hurt. Same with healing crystals, reiki and prayer. So, if a person wants to engage in these activities, and they are perfectly safe physically, be my guest. Other modalities, such as chiropractic, acupuncture, herbalism and the like, definitely need to be evaluated more stringently, as there is reason to think that they may cause harm.

This is a common position to take. Val Jones at SBM coined the term “shruggie” to refer to this position – in essence, if there is no direct harm, then who cares what people do. First, as I discussed very recently on SBM, there are many types of harm from unscientific medical modalities other than direct physical harm. So I do not find this position tenable for that reason alone.

Further, context is everything. There are actually a variety of positions that authors at SBM take when it comes to regulating medical practice. We all generally believe that medical professionals should not engage in nor promote unscientific methods. In fact, we should oppose their adoption and promotion, we should oppose their inclusion in universities and mainstream hospitals, and spending public funds on researching extremely implausible or already disproven modalities. That seems to be a point of difference between myself and Zilberberg.

I personally do not oppose individuals doing whatever they want when it comes to their own health. If you want to chew on tree bark (a vivid example given to me by someone else), go right ahead. What I object to is someone selling the tree bark and claiming that it cures cancer based upon nothing but legend and anecdote, and scaring their customers away from proven therapies in order to make the sale. I object to distortions of logic and science in order to confuse the public so as to better market worthless or harmful products. And I object to medical professionals looking the other way out of misguided political correctness, or simply a naivete as to the significant harm that is done.

SBM has a huge consumer protection mission, and it puzzles frustrates me that this mission is so often and so thoroughly misrepresented. This misrepresentation is deliberate – part of the “health freedom” movement – and seeks to portray all health care consumer protection activity as arrogant elitism and protectionism. This is identical to the intelligent design movement’s representation of all attempts at quality control in education as arrogant elitism.

What I don’t understand is Zilberberg’s apparent position that, while she knows homeopathy is utterly worthless, a physician should refrain from telling her patients exactly that.

Vaccine Skepticism

Zilberberg goes on to argue that she is not anti-vaccine, as she has been accused (not by me). I have no reason not to accept her word on this, and it is good that she has clarified her position.

But I do think she is displaying a lack of appreciation for the nature of the anti-vaccine movement. As an example, if one publicly expresses doubt about an aspect of currently accepted Darwinian evolution it would be nice if they understand the many ways in which the scientific discourse is exploited by creationists, so that they don’t accidentally give succor to an anti-scientific movement.

Likewise, any public discussion about vaccines, while it should be candid and completely honest, should ideally be done with an adequate familiarity with the anti-vaccine movement’s propaganda so that one’s words and positions are not easily exploited. In fact, while expressing skepticism about a particular vaccine or vaccine program, I would recommend specifically clarifying one’s position to distance themselves from the extremists. Otherwise you are inviting misinterpretation.

Conclusion

The take home message from this exchange is that, in my opinion, accusations of using harsh tone or of arrogance are an ad hominem distraction from the real issue – what is the optimal relationship between the practice of medicine and the underlying science of medicine.

Zilberberg engaged fully in this distraction, but is now slowly backing away (but not enough, in my opinion). I think this was largely due to the fact that she has been taken in by the very active and sophisticated propaganda campaigns of CAM proponents. She seems to have bought into their rhetoric, and did not read carefully enough into our writing at SBM to see through it.

We are approaching 1000 blog posts at SBM. I don’t expect critics to read every post, but a tiny bit of scholarly due diligence would be nice, before essentially buying into the lies and distortions of our critics.

We at SBM write frequently about the complexity and limitations of the science of medicine. That is our mantra – a nuanced and sophisticated approach to evidence is needed. But at the end of the day,  some treatments are better than others. We can accept and reject practices based upon plausibility and evidence, even while there is a vast gray zone in the middle where we just don’t know yet.

It is misleading and ironic in the extreme to criticize promoters of SBM for taking a simplistic approach to evidence. That is the opposite of the truth. Meanwhile, promoters of all sorts of so-called CAM do take a simplistic and highly distorted approach to evidence, display an intolerance of uncertainty, systematically misrepresent the evidence to their clients and the public, think in stark black-and-white terms, engage in bait-and-switch deceptions, distort the positions of their critics, rely upon low grade evidence and logical fallacies for their claims, and then hide behind political correctness, post-modernism, distractions about “health care freedom”, special pleading (science can’t test my claims), and accusations of arrogance and paternalism.

All of this behavior is carefully documented in the pages of Science-Based Medicine. Would-be critics of SBM should try reading some of them before launching into misguided criticism of what is ultimately a straw man of our actual positions.

I take Zilberberg at her word that she is interested in genuine discussion, and she has at least moved in that direction. I recommend she step back, read some more of SBM and see what we actually have to say about science and medicine.

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14 responses so far

14 Responses to “Dr. Zilberberg Responds”

  1. Oracon 26 Oct 2010 at 11:35 am

    Incidentally, having written about medicine for years I have definitely seen a strong pattern. When I criticize the logic and factual premises of another person’s argument I am frequently accused of being mean by people who then attack me personally. It seems many people do not understand the difference between a strong but substantive criticism and a personal attack.

    Indeed.

    True, I do have a penchant for using terms like “burning stupid,” but I usually reserve them for people who (like certain leaders of the anti-vaccine movement) who willfully spread misinformation and pseudoscience even after having been corrected many, many times. Dr. Zilberberg may not believe it, but in response to her post I took special care not to attack her personally, although I did indeed strongly attack her arguments, straw men mischaracterizations of SBM, and flaws in her reasoning using metaphors like “taking a flamethrower to straw men” to describe what I was doing. Hopefully she can see the difference. Regardless, the point is, even smart people sometimes use really bad arguments, which is what Dr. Zilberberg was doing. Clearly, to some degree she realizes this now. At least, as loathe as she appears to be to back off completely, she realizes that her statement about how all treatments should be treated with “equipoise” was so wrong it wasn’t even wrong.

    I’m also still concerned about her attitude towards vaccines, though. She may not be “anti-vaccine,” but some comments she made on my blog months ago, coupled with the “skeptical” attitude towards certain vaccines, lead me to worry that she’s drunk a bit of the Kool Aid when it comes to anti-vax. I hope I’m wrong, but I’ve seen statements like that so many times that they always start the spider senses tingling.

  2. Adam_Yon 26 Oct 2010 at 1:54 pm

    My belief is that all modalities that may impact what happens to public’s health need to be evaluated for safety, not question. I think we both agree, since there is really no reason to think that something like homeopathy has anything that can help, by the same token we do not believe that it have anything that can hurt. Same with healing crystals, reiki and prayer.

    As someone on Orac’s blog all ready pointed out. Her claim of homeopathy being harmless directly coincided with a rash of poisoning due to homeopathic teething tablets that contains belladonna.

  3. Todd W.on 26 Oct 2010 at 2:40 pm

    @Adam_Y

    That was me. I wrote about the FDA recall of Hyland’s Homeopathic Teething Tablets that are labeled as containing Belladonna 3X, but which were found to contain varying amounts of nightshade. The danger was made worse by the product not having child-proof caps for the bottles.

  4. lizditzon 26 Oct 2010 at 5:31 pm

    But I do think she is displaying a lack of appreciation for the nature of the anti-vaccine movement. As an example, if one publicly expresses doubt about an aspect of currently accepted Darwinian evolution it would be nice if they understand the many ways in which the scientific discourse is exploited by creationists, so that they don’t accidentally give succor to an anti-scientific movement.

    Likewise, any public discussion about vaccines, while it should be candid and completely honest, should ideally be done with an adequate familiarity with the anti-vaccine movement’s propaganda so that one’s words and positions are not easily exploited. In fact, while expressing skepticism about a particular vaccine or vaccine program, I would recommend specifically clarifying one’s position to distance themselves from the extremists. Otherwise you are inviting misinterpretation.

    Exactly. It’s important to note that there are several wings of the anti-vaccination movement. One wing is the “autism=vaccine injury”. Another is…I don’t know what to call it — the “vaccines are unnatural and they harm health” wing, most often found on chiropractic sites.

    But all share a common feature: the unshakable belief that if a vaccine isn’t 100% safe (without side effects) and 100% effective in preventing later infection, then vaccines are useless.

    I personally do not oppose individuals doing whatever they want when it comes to their own health. If you want to chew on tree bark (a vivid example given to me by someone else), go right ahead. What I object to is someone selling the tree bark and claiming that it cures cancer based upon nothing but legend and anecdote, and scaring their customers away from proven therapies in order to make the sale.

    This is exactly why I object so strenuously to the mistaken belief that “autism = vaccine injury”. It leads to a host of expensive, unproven, and often injurious treatments, of which chelation is just the tip of the iceberg.

    Here are Dr. Zilberberg’s words, from the October 1 blog post “Are Vaccines Safe?”

    http://evimedgroup.blogspot.com/2009/10/are-vaccines-safe.html

    Rabid vaccine advocates would argue that there is never a need to make individual decisions in diseases where a vaccine is available. Well, let’s take the chicken pox vaccine. Here is a childhood disease that is indeed highly contagious, but only causes a self-limited nuisance illness with a very low risk of complications in the pediatric age group without underlying conditions. In the US the disease was associated with ~10,000 hospitalizations and on average 105 deaths annually in the pre-vaccine era. So, is this really a big deal? Well, yes, from the perspective of those families suffering the 105 fatalities. But what about the societal concern?

    I object to the word choice (“rabid”, and in a later not-quoted paragraph, “vaccine apologists” ). This is not unbiased language at all. To me it seems to reveal a bias of Zilberberg’s own.

    I also object to the strawman of ” never a need to make individual decisions in diseases”. Parents do indeed make individual decisions, on behalf of their children, and adults do it routinely relevant to their own immunizations.

    Finally, relative to mandatory varicella vaccination and societal costs: those 10,000 hospitalizations a year aren’t a free good.

    http://www.infectiousdiseasenews.com/article/76907.aspx

    The varicella vaccination program may have prevented about 50,000 varicella-associated hospitalizations in the United States during this time, Adriana Lopez, MHS, of the CDC, said during a press conference at the 48th Annual Meeting of the Infectious Disease Society of America.

    To be fair to Dr. Zilberberg, that’s a recent study, and the data she was reasoning with in her post indicated that the primary motivation for mandating varicella vaccination was in fact the economic cost to parents, from staying home with ill children. But even then I question her reasoning.

    I now believe that high uptake rates for vaccine-preventable diseases is also a social-justice issue. The costs of contracting childhood vaccine-preventable diseases fall disproportionately on the poor, who have less access to health care. The burden on a working mother who has to stay home to care for an ill child is especially heavy on the working poor, who may not have vacation time as an employment benefit.

  5. Adam_Yon 26 Oct 2010 at 6:02 pm

    That was me. I wrote about the FDA recall of Hyland’s Homeopathic Teething Tablets that are labeled as containing Belladonna 3X, but which were found to contain varying amounts of nightshade. The danger was made worse by the product not having child-proof caps for the bottles.

    3X belladonna sounds like to me that there isn’t even enough dilution for there to be a true homeopathic drug (IE. can’t have a physiological effect.) It sounds like part of the problem is what occurred with ziccam.

  6. Todd W.on 26 Oct 2010 at 10:43 pm

    @Adam_Y

    Yep. Zicam was a 2X dilution of zinc. Typical homeopathic products tend toward the 12C-30C range (i.e., dilutions into 100 parts water/alcohol, vs. 10 parts for X dilutions).

  7. ccbowerson 26 Oct 2010 at 11:49 pm

    “Zicam was a 2X dilution of zinc”

    I’m not sure that they make that product anymore (the zinc nasal spray). Zicam seems to have a whole line of OTC medications mixed with homeopathic “remedies.”

    I abhor the way that companies are allowed to “market” their products in homeopathic and OTC land… using brand names that are confusing and making it difficult to see what ingredients are actually in products… and being able to change in the active ingredients while using the same brand name. Go look at a website for an OTC product and see how hard it is to actually know what you are taking. Zicam itself is now 20 different products, some “homeopathic” and some with pharmacologically active ingredients.

  8. ChrisHon 27 Oct 2010 at 12:10 am

    Liz Ditz:

    The burden on a working mother who has to stay home to care for an ill child is especially heavy on the working poor, who may not have vacation time as an employment benefit.

    My kids got chicken pox the year before there was a vaccine. Because it was passed from one child to the others with a two week delay, it meant a whole month of misery.

    I remember being miserable with it when I got it as a kid… and being miserable for the month I took care of three kids. One of them being only a baby, who could not sleep because of the pain.

    It also swept through the school, where we did get the notice to not let sick kids go to school. There was at least one immune compromised child attending who had to stay away (I was helping the nurse when she let out her frustration about a loony parent who sent a kid with a fever to school with a bottle of Tylenol!). One kid from the school did end up in the hospital with a very real chance of losing a leg due to a secondary bacterial infection (and no, I did not find out what happened through the mom network).

    I don’t understand why anyone would rather have a child go through a disease that involves open pustules in the form of very itchy pox, instead of getting a vaccine. With the added bonus of a real chance of shingles later in life. It boggles the mind.

  9. Adam_Yon 27 Oct 2010 at 9:08 am

    I know they still make a knockoff version of ziccam because my one coworker was taking it recently.

  10. Skepticoon 27 Oct 2010 at 10:46 am

    I think we both agree, since there is really no reason to think that something like homeopathy has anything that can help, by the same token we do not believe that it have anything that can hurt.

    Tell that to Gloria Sam. Oh wait, you can’t: she’s dead.

    I also do not oppose adult individuals doing whatever they want when it comes to their own health. Forcing quackery on children who have no choice – that’s different.

  11. Oracon 27 Oct 2010 at 11:03 am

    Exactly. It’s important to note that there are several wings of the anti-vaccination movement. One wing is the “autism=vaccine injury”. Another is…I don’t know what to call it — the “vaccines are unnatural and they harm health” wing, most often found on chiropractic sites.

    Indeed. There is a continuum of thought (if you can call it that) among antivaxers, from those who think that vaccines are dangerous beyond all belief to those who think they are unnatural and that it’s better to get the disease naturally to achieve immunity (good luck with that for the more harmful diseases!) to those who think that vaccines just don’t work to those who concede that some vaccines work but just don’t like The Man telling them they need to vaccinate themselves and/or their children. She probably doesn’t realize it, but Dr. Zilberberg’s rhetoric echoes that of the last category (at least in other posts), where she concedes vaccines are “useful” for highly infectious and dangerous diseases but pooh-poohs them for diseases like chicken pox or preventing HPV infection.

    She’s also referred to vaccine defenders as “rabid” and accused them of “hysteria,” likening them to antivaxers :

    http://evimedgroup.blogspot.com/2009/10/are-vaccines-safe.html

  12. elmer mccurdyon 28 Oct 2010 at 3:11 am

    It’s hard to discuss all these generalizations in part because I’m not interested in obvious silliness like homeopathy, being pretty narrowly focused on my own condition, that is to say pain and related symptoms caused by trigger points, which I had to learn to self-treat after finding that common-practice approaches were making them worse – however, just for future reference, I think it would be useful to put the claims of that veterinarywatch article in more simplistic terms: about a third of common medical practices are backed by random controlled trials, a quarter by no compelling evidence, and the remainder by some other kind of undefined “compelling evidence.”

  13. elmer mccurdyon 28 Oct 2010 at 3:50 am

    Anyway here are some other data that I happened to have bookmarked.
    http://clinicalevidence.bmj.com/ceweb/about/knowledge.jsp

  14. elmer mccurdyon 29 Oct 2010 at 5:07 am

    It just occurred to me that I said something that could be misinterpreted. The “common practices” that made my symptoms worse were NOT trigger point therapy, but rather strengthening physical therapy exercises.

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