26 Aug 2010


But people who draft management guidelines are conscientious and world-renowned experts. They would not allow their potential conflicts of interest interfere with their judgment and recommendations, right?

Yes and no. I tend to trust that most guidelines reflect what the authors believe and are not for financial and political gains. Nevertheless, the recommendations can still be biased. In our field, colonoscopy surveillance for colorectal cancer prevention is a big business. In some countries, there are clinicians who would call themselves colonoscopists, more or less telling you that they would not do much else. However, one cannot ignore the fact that the effect of colonoscopy surveillance on overall and cancer-related mortality has not been tested by randomized controlled trials. In addition, there is accumulating evidence to show that colonoscopy does not save more lives than flexible sigmoidoscopy, a simpler procedure that does not require thorough bowel cleansing and sedation, not to mention the lower complication rate.

With this background, you probably would expect that experts should support the simpler procedure. Nevertheless, searching through the literature, many experts (notably gastroenterologists) still state colonoscopy as the preferred surveillance method.[N Engl J Med 2009;361:1179-87] The rationales such as more thorough examination and the inclusion of proximal colon are more theoretical than evidence-based. Again, in this particular case I do not doubt the experts recommend colonoscopy for their own benefits. They are so senior that I cannot imagine they are still making a living by doing endoscopies. The biased view merely stems from their background and thus health beliefs.

Therefore, the medical committee is suggesting a revisit of the guideline drafting process. In essence, experts in one particular field should mainly provide relevant evidence but not have overwhelming influence on the final recommendation statements.

P.S. If you search PubMed for articles on CT colonography, it would be funny to note that around half of the articles said that this new radiological technique is extremely good and half said its performance is suboptimal and not ready for routine clinical use. If you note the affiliations of the first authors, the former articles were all written by radiologists and the latter were by, you got it, gastroenterologists. This time, we are talking about real business.

19 Aug 2010


Recently, our managers are striving to control the drug budget. Every team is requested to submit an innovative idea to reduce expenditure.

At lunch, AT complained that even an inexpensive drug was tightly controlled although current guidelines had already recommended the most expensive agent as first-line treatment.

“Mind you,” S replied, “most guidelines are written by international experts with much conflict of interest. Not surprisingly, companies selling the newest and most expensive drugs have a lot of influence.”

“You don’t have conflict of interest. You should sit in those panels,” EW suggested.

“Oh, it doesn’t work this way,” said S. “In their eyes, the very fact that I do not have conflict of interest is good enough proof that I am not an expert.”

12 Aug 2010


In one chapter, Gladwell described how the US security expert Gregory Treverton distinguished between puzzles and mysteries. Puzzles are there when we lack some essential information to a factual answer. If we obtain that information, we get the answer. For example, Osama bin Laden’s whereabouts are a puzzle. If you hunt down high ranking people in Al Qaeda who knows his hiding place, you find the answer.

In contrast, mysteries require judgments and the assessments of uncertainty. For example, what would happen to Iraq after overthrowing Saddam Hussein was a mystery. You cannot get the answer even if his officials and sons honestly reply to your every question. The major difference between puzzles and mysteries is that in the latter condition, you are not having insufficient information. You just cannot make use of the information at hand.

Of course, not every one would agree to the definitions. However, when you are trying to solve a problem, it is useful to think why you have not got the answer yet and how the answer can be obtained. Without the insight, wrong moves will get you nowhere.

Many medical students spend countless hours reading textbooks and lecture notes without realizing that their future job demands mostly the ability to solve mysteries. If I ask you the tests for diagnosing pulmonary embolism, it is a simple puzzle one can solve by reading a textbook. The trouble is patients never ask you what the diagnostic tests are. They just tell you a symptom and show abnormalities here and there. If you cannot make the diagnosis, it is unlikely because you have not heard of pulmonary embolism before. Instead, you are probably overwhelmed by the information you cannot fully interpret and organize. Simply said, the answer is not in a textbook.

5 Aug 2010


My recent bedtime reading is What the Dog Saw and Other Adventures by Malcolm Gladwell. This is a collection of his writing from The New Yorker. I seldom read this kind of recycled publications, but the temptation is too great after enjoying his famous books previously – The Tipping Point, Blink and Outliers.

While flipping through the pages and wondering whether to buy the book, a few lines in the preface touched me. Gladwell mentioned he was often asked where his ideas came from. If you have read his books, you would probably agree that he is a wizard in suggesting interesting answers to explain everyday phenomena. So how did he do it? He explained that most people considered most things uninteresting. What he did was to convince himself everyone has a story to tell.

This is no different from scientific research. At the end of the nineteenth century, scientists have studied thoroughly many areas of the physical world – electricity, optics, kinetics, to name a few. Many wise men held the belief that there was not much left to study in science. Looking back, we of course know how wrong they were. Relativity, quarks and DNA are just some examples of major breakthroughs that they have never imagined.

In clinical medicine, I have repeatedly heard youngsters complaining the ‘big’ questions have all been answered. Their view is certainly shared by many people in history, but so far all of them were proved to be wrong. If you are not satisfied with current beliefs and keep asking questions, well, the world is an interesting place after all.