Making a case for evidence-based medicine
KATHMANDU, JUL 09 -
Not very long ago, medical knowledge used to be the sole property of medical practitioners, obscure and inaccessible to commoners. When doctors decided on a treatment, patients would have to take their advice, no questions asked. The doctor-patient relationship resembled that of a master and disciple, where doctors often presumed that it would be futile to explain medical particulars to someone who wouldn’t understand anyway In today’s modern era of proliferating information technology, however, knowledge is no longer bound to experts alone. Common people are now well-informed, sometimes even more than the professionals themselves. The paradigms of the doctor-patient relationship is changing—a welcome trend-where patients have become an active part of the decision-making process. But then again, the excess of information means that there are risks of wastage of resources and damage being caused by rash actions, inadequate knowledge and wrong information, oftentimes worse than being completely ignorant. One of the major reasons for this is because people are unaware that all available information is not accountable.
Fifteen years ago, a friend of mine who had a PhD in business administration, conducted a small survey in Kathmandu that demonstrated how people were more reliant on word of mouth compared to educational strategies. This is perhaps still true, and is widely exploited in the business sector. The most common strategy is to get someone—preferably a popular public figure—to endorse the product or service, usually presented as the result of scientific research. The medical field has, of late, joined the game. Although it is ethically and legally questionable to put forth advertisements with the express intention of increasing profit, we still see and hear such commercials in the media: tall claims that certain medication, treatment, hospital or even doctors are superior to others and therefore covetable. Many times, these materials are served up not as overt classified ads, but disguised as news articles or the common notice of felicitation. And the naïve public (sometimes even medical practitioners themselves) fall easy prey, oblivious of how they are being manipulated by the advertisers.
These claims are generally very far from the truth, a contortion of facts that shouldn’t be trusted at face value. It is therefore worthwhile to learn about how researches are actually conducted and evidence generated. Of course, research methodology is a complicated topic, and advertisers seldom explain the process in detail, but there are some basic rules that could be enlightening for the average consumer.
A 100 percent guarantee does not exist, even in the best of medical research. The standard acceptable margin of error lies between one to five percent, which means that the best possible prediction is never more than 95-99 percent accurate. And claims like ‘absolutely no side effects’ are also impractical, even when it comes to herbal or other natural products. The definition of ‘side effect’ is simply effects other than the intended one, so even drinking water can have some side effect or the other (cold sensation, urge to urinate, for example). And an individual’s endorsement based on experience is also not enough evidence; decent clinical trials need to be conducted. Even for properly done researches, the strength of the evidence is determined by study design, as shown below:
Strength of Evidence (in ascending order):
Strength of Evidence (in ascending order):
1. A case report/expert’s opinion is considered the weakest evidence. The logic behind this is that even if a treatment applies to an individual, it may not have the same results in others. Besides, one single case report does not prove that a particular intervention is the only factor behind whatever effect it has had. There are examples of patients who have improved thanks to a ‘placebo’, which assure them psychologically of benefits but really do nothing physically. And some diseases are simply time bound and subside after a particular period, without any treatment at all.
2. A case series has slightly higher reliability compared to a single case. But it does boast the same shortcomings as mentioned above.
3. Cross sectional studies can
estimate incidences and prevalence of diseases but are not very adept at determining cause and effect relationships.
4. In case control studies, research is done in two groups—the ill and the healthy. This design is usually useful in eliminating confounding factors.
5. In cohort studies, a group of homogenous people is longitudinally studied to determine cause and effect.
6. Clinical trials are the best way to establish cause and effect. The best evidence can be generated if the selection of the subjects is carried out on a random basis. It is even better if the intervention can be kept secret from both the examiner and the participants, so that the placebo effect and human biases are rooted out.
It is clear that claims based on scientific research are inadequate, and it is the design and the actual research process that one must look into to. It is probably pointless to state that authorised government bodies need to scrutinise and disseminate health related information, because as in most sectors, the government falls behind in this one too. Therein lies the significance of public awareness and the contribution of activists. It their collective responsibility to ensure evidence-based medicine instead of baseless quackery.
Dr Shakya is the Associate Professor and Chair of the Department of Psychiatry at the Patan Academy of Health Sciences, and the General Secretary of the Psychiatrists’ Association of Nepal
Posted on: 2012-07-09 08:40