Thursday, December 30, 2010

Dr. Palmquist continues to abuse science on HuffPo.

I wrote last summer about Dr. Richard Palmquist's first post on Huffington Post, and how his idea of science does not match science as most people understand it. He continues to rely heavily on emotional anecdotes, confuses correlation with causation, and lists a lot of scientific sounding references which usually are of poor quality or do not support his conclusions. In his most recent post, he continues the pattern he established with his first post, but this time promoting the homotoxicolgy ideas he is fond of as scientific advances.

He begins his post with a description of  an old cocker spaniel with multiple benign skin tumors that is about to have surgery to remove the masses. As in his other posts, Dr. Palmquist presents these anecdotes in such a dramatic and emotional fashion that it is difficult to tell if he is describing the case accurately, exaggerating, or just making up a good story. That said, I don't know that I have seen a 13 year old cocker spaniel that did not have multiple sebaceous adenomas. Sebaceous adenomas, cysts and other benign masses on or just under the skin are very common in older dogs, and are even more prevalent in certain breeds such as cocker spaniels. I am not sure why anyone thought it was necessary to remove all of the adenomas-as small benign tumors it is fairly common to leave them alone and simply monitor them for problems like inflammation, infection or bleeding. If benign masses like sebaceous adenomas are stable and not causing any problems, most veterinarians will not insist on removing them surgically, and sometimes they will resolve on their own. Often they will bother the animal's owner more than the animal, which is one reason to remove them, and since they are usually fairly small, superficial skin  tumors, they can often be removed fairly easily using a reversible sedative, local anesthetics, and a few days of fairly safe pain relievers, so Dr. Plamquist's representation of the surgery as quite painful, seems like an exaggeration, as well as the impression that not doing the surgery is some kind of revolutionary idea on his part.  Where He really goes off the rails however, is in his representation to the owner that the adenomas, which very likely have a genetic component to their development because of their high incidence in certain breeds, are caused by ill-defined "toxins" and should be treated with a variety of homeopathic preparations. If the adenomas really resolved on their own as Dr. Palmquist describes, it is more likely to be a result of inflammation related to the previous biopsies (described as "special testing" in the post) or simply a coincidence than due to the homeopathic remedies he provided. Some of the remedies made by Heel are low dilutions, so there is the possibility that there was some active ingredient in the treatment, but the dose was still likely to be very small. Amusingly, the one mass that did not resolve on it's own is explained away as being on an acupuncture point. Somehow the point or the tumor magically "knows" something and is trying to tell us the dog needs it there to maintain circulation to the brain and cognitive ability. There are some Chinese studies that claim to demonstrate this type of benefit, but unfortunately nearly all studies of acupuncture from china are positive, suggesting publication and other biases, which make it difficult to evaluate such studies. There has not been any research replicating these findings elsewhere. Because of this magical location on an acupuncture point, they decided to watch the tumor, which has been stable for years. As I said before, many veterinarians will do the same thing with no need to come up with magical rationalizations for it.

These ideas come from a early to mid 20th century offshoot of homeopathy called "homotoxicolgy". Hans-Heinrich Reckeweg, the inventor of homotoxiclogy, denied the germ theory of infectious disease and included vaccines and pharmaceutical treatments in the "toxins" which he thought needed to be removed from the body. Heel, the company founded by Reckeweg, has been in trouble in the past for fraudulent claims and marketing of it's products, and a review of randomized trials of Heel products by Edzard Ernst and K. Schmidt revealed serious flaws in the studies and a lack of evidence supporting their use. For a self-proclaimed "research geek", the references Dr. Palmquist supplies to support his views seem to be accepted credulously and uncritically, and perhaps with the expectation that nobody will actually check to see what the references actually say. Most of the studies are in-vitro, preliminary and published in questionable journals such as Medical Hypotheses or alternative medicine journals which are often uncritical of poor studies and biased toward promoting their particular modality. One of the references has been thoroughly discussed by Dr. Rachie and Orac, (shockingly, the 87% alcohol used as diluent for the remedies is toxic to cancer cells in vitro!) the Cochrane review provides very weak support despite being authored by homeopaths. the authors concluded; 
     "This review found preliminary data in support of the efficacy of topical calendula for prophylaxis of acute  dermatitis during radiotherapyand Traumeel S mouthwash in the treatment of chemotherapy-induced stomatitis. These trials need replicating. There is no convincingevidence for the efficacy of homeopathic medicines for other adverse effects of cancer treatments. Further research is required."
The one study of companion animals published in a more mainstream journal (Neumann S, Stolt P, Braun G, Hellmann K, Reinhart E. 2010. Effectiveness of the Homeopathic Preparation Zeel Compared with Carprofen in Dogs with Osteoarthritis. J Am Anim Hosp Assoc. Dec 16. [Epub ahead of print]) was uncontrolled, unblinded, and has other problems, including an average age difference of nearly 3 years between the two treatment groups, with the younger group recieving the homeopathic remedy. This study was also funded by Heel, the producer of the homeopathic remedy.

Finally, Dr. Palmquist describes how he thinks medicine should "work", by which he means new therapies should be developed. Unfortunately, the order of investigation he describes is somewhat backward. Plausibility should be the first test for any treatment, and his statement that homeopathic remedies have been proven to work and have understandable mechanisms flies in the face of our understanding of basic physics and chemistry, and is only accepted by true believers in homeopathy. Anecdotal evidence for effectiveness is not a reliable way to discover new treatments and is only a very preliminary way  to start to investigate a new treatment. Exceedingly implausible treatments like homeopathy are probably not worth studying further, as preliminary weakly positive results are likely to be the result of bias, coincidence and random chance. These type of preliminary positive results seem to always disappear in better designed trials of homeopathy. While I am sure Dr. Palmquist means well, he is a poster child for demonstrating how cognitive errors and wishful thinking can lead us down a path full of dead ends and useless therapies. Unfortunately, his influence as president of the AHVMA and a member of AAHA gives him an undeserved platform to promote his delusions. In this case, no harm was done to the patient, but sometimes the result is not so good.

Life and Death in the winter snow.

I noticed feathers falling past my front window this afternoon and looked outside to find this Sharp-Shinned Hawk eating a small bird in the Ponderosa Pine tree in the front yard. The temperature outside was 13 degrees Fahrenheit. A small bird needs to consume a lot of calories to survive in these temperatures.

Wednesday, December 8, 2010

Twisting facts to suit "theory". How smart people can fool themselves.

              “It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories instead of theories to suit facts.”
Sir Arthur Conan Doyle

   It often seems strange how frequently smart, well educated people seem to fall for pseudoscience. Doctors and Veterinarians are certainly no exception, and it is not unusual to see veterinarians recommending poorly evidenced treatments or even treatments with evidence against their effectiveness. People often ask how a trained medical professional can fall for such things and then promote them. In addition to regression to the mean, selection bias and other cognitive errors, we are all prone to the illusion of control. A recent paper in the British Journal of Psychology (discussion by Ben Goldacre here as the entire paper is behind a paywall) helps to demonstrate how this illusion can develop in medical professionals and suggests some ways to avoid it. Unfortunately, many veterinary school curricula and continuing education rely heavily on a fairly authoritarian presentation of information and rote memorization that do not help students to learn to evaluate claims critically and understand the evidence base behind various treatments.

  In recent comments on The SkeptVet Blog, several different people have suggested that skeptics should not criticize alternative treatments until they have tried them.This advice is given without an awareness of how easily we all make cognitive errors and how those errors can give us an illusory view of the effectiveness of our treatments. To be fair, we are all just as susceptible to this type of cognitive error no matter what type of treatment we are using, and we should always be wary of misdiagnosis or inappropriate treatment selection, situations in which these types of cognitive errors are common in both evidence based and alternative medical treatments. It underlines the importance of blinded, controlled trials, and the evaluation of the strength of the evidence supporting any treatment in  as objective a way as possible. "Trying it for yourself" is just a good way to fool yourself, and the more confident you are in your experience and ability, the more likely you are to believe that an ineffective treatment works. This new psychological paper just demonstrates the idea again in a relevant way.