Monthly Archives: September 2014
Medical treatments with no direct effect, such as homeopathy, are surprisingly popular. But how does a good reputation of such treatments spread and persist? Researchers from the Centre for the Study of Cultural Evolution in Stockholm believe that they have identified the mechanism.
They argue that most medical treatments result in a range of outcomes: some people improve while others deteriorate. If the people who improve are more inclined to tell others about their experiences than the people who deteriorate, ineffective or even harmful treatments would maintain a good reputation.
They conducted a fascinating study to test the hypothesis that positive outcomes are overrepresented in online medical product reviews, examined if this reputational distortion is large enough to bias people’s decisions, and explored the implications of this bias for the cultural evolution of medical treatments.
The researchers compared outcomes of weight loss treatments and fertility treatments as evidenced in clinical trials to outcomes reported in 1901 reviews on Amazon. Subsequently, in a series of experiments, they evaluated people’s choice of weight loss diet after reading different reviews. Finally, a mathematical model was used to examine if this bias could result in less effective treatments having a better reputation than more effective treatments.
The results of these investigations confirmed the hypothesis that people with better outcomes are more inclined to write reviews. After 6 months on the diet, 93% of online reviewers reported a weight loss of 10 kg or more, while just 27% of clinical trial participants experienced this level of weight change. A similar positive distortion was found in fertility treatment reviews. In a series of experiments, the researchers demonstrated that people are more inclined to begin a diet that was backed by many positive reviews, than a diet with reviews that are representative of the diet’s true effect. A mathematical model of medical cultural evolution suggested that the size of the positive distortion critically depends on the shape of the outcome distribution.
The authors concluded that online reviews overestimate the benefits of medical treatments, probably because people with negative outcomes are less inclined to tell others about their experiences. This bias can enable ineffective medical treatments to maintain a good reputation.
To me, this seems eminently plausible; but there are, of course, other reasons why bogus treatments survive or even thrive – and they may vary in their importance to the overall effect from treatment to treatment. As so often in health care, things are complex and there are multiple factors that contribute to a phenomenon.
It has been estimated that 40 – 70% of all cancer patients use some form of alternative medicine; may do so in the hope this might cure their condition. A recent article by Turkish researchers – yet again – highlights how dangerous such behaviour can turn out to be.
The authors report the cases of two middle-aged women suffering from malignant breast masses. The patients experienced serious complications in response to self-prescribed use of alternative medicine practices to treat their condition in lieu of evidence-based medical treatments. In both cases, the use and/or inappropriate application of alternative medical approaches promoted the progression of malignant fungating lesions in the breast. The first patient sought medical assistance upon development of a fungating lesion, 7∼8 cm in diameter and involving 1/3 of the breast, with a palpable mass of 5×6 cm immediately beneath the wound. The second patient sought medical assistance after developing of a wide, bleeding, ulcerous area with patchy necrotic tissue that comprised 2/3 of the breast and had a 10×6 cm palpable mass under the affected area.
The authors argue that the use of some non-evidence-based medical treatments as complementary to evidence-based medical treatments may benefit the patient on an emotional level; however, this strategy should be used with caution, as the non-evidence-based therapies may cause physical harm or even counteract the evidence-based treatment.
Their conclusions: a malignant, fungating wound is a serious complication of advanced breast cancer. It is critical that the public is informed about the potential problems of self-treating wounds such as breast ulcers and masses. Additionally, campaigns are needed to increase awareness of the risks and life-threatening potential of using non-evidence-based medical therapies exclusively.
I have little to add to this; perhaps just a further reminder that the risk extends, of course, to all serious conditions: even a seemingly harmless but ineffective therapy can become positively life-threatening, if it is used as an alternative to an effective treatment. I am sure that some ‘alternativists’ will claim that I am alarmist; but I am also convinced that they are wrong.
Recently, I was invited to give a lecture about homeopathy for a large gathering of general practitioners (GPs). In the coffee break after my talk, I found myself chatting to a very friendly GP who explained: “I entirely agree with you that homeopathic remedies are pure placebos, but I nevertheless prescribe them regularly.” “Why would anyone do that?” I asked him. His answer was as frank as it was revealing.
Some of his patients, he explained, have symptoms for which he has tried every treatment possible without success. They typically have already seen every specialist in the book but none could help either. Alternatively they are patients who have nothing wrong with them but regularly consult him for trivial or self-limiting problems.
In either case, the patients come with the expectation of getting a prescription for some sort of medicine. The GP knows that it would be a hassle and most likely a waste of time to try and dissuade them. His waiting room is full, and he is facing the following choice:
- to spend valuable 15 minutes or so explaining why he should not prescribe any medication at all, or
- to write a prescription for a homeopathic placebo and get the consultation over with in two minutes.
Option number 1 would render the patient unhappy or even angry, and chances are that she would promptly see some irresponsible charlatan who puts her ‘through the mill’ at great expense and considerable risk. Option number 2 would free the GP quickly to help those patients who can be helped, make the patient happy, preserve a good therapeutic relationship between GP and the patient, save the GP’s nerves, let the patient benefit from a potentially powerful placebo-effect, and be furthermore safe as well as cheap.
I was not going to be beaten that easily though. “Basically” I told him “you are using homeopathy to quickly get rid of ‘heart sink’ patients!”
He agreed.
“And you find this alright?”
“No, but do you know a better solution?”
I explained that, by behaving in this way, the GP degrades himself to the level of a charlatan. “No”, he said “I am saving my patients from the many really dangerous charlatans that are out there.”
I explained that some of these patients might suffer from a serious condition which he had been able to diagnose. He countered that this has so far never happened because he is a well-trained and thorough physician.
I explained that his actions are ethically questionable. He laughed and said that, in his view, it was much more ethical to use his time and skills to the best advantage of those who truly need them. In his view, the more important ethical issue over-rides the relatively minor one.
I explained that, by implying that homeopathy is an effective treatment, he is perpetuating a myth which stands in the way of progress. He laughed again and answered that his foremost duty as a GP is not to generate progress on a theoretical level but to provide practical help for the maximum number of patients.
I explained that there cannot be many patients for whom no treatment existed that would be more helpful than a placebo, even if it only worked symptomatically. He looked at me with a pitiful smile and said my remark merely shows how long I am out of clinical medicine.
I explained that doctors as well as patients have to stop that awfully counter-productive culture of relying on prescriptions or ‘magic bullets’ for every ill. We must all learn that, in many cases, it is better to do nothing or rely on life-style changes; and we must get that message across to the public. He agreed, at least partly, but claimed this would require more that the 10 minutes he is allowed for each patient.
I explained….. well, actually, at this point, I had run out of arguments and was quite pleased when someone else started talking to me and this conversation had thus been terminated.
Since that day, I am wondering what other arguments exist. I would be delighted, if my readers could help me out.
