Tuesday, October 16, 2012
The changing nature of truth, answering questions for a chance to win a free MKSAP subscription and should we now stop using warfarin (mostly) for atrial fibrillation?
Just recently in my e-mail I got an invitation from the makers of the MKSAP (the medical knowledge self assessment program which I used in studying for my internal medicine boards) to answer a set of not-ready-for-primetime questions in the various subspecialties, for which I will be rewarded with a chance to get the next MKSAP materials for free. I must answer these questions without using outside materials and the answers from all of the folks who do this will be used to standardize the test.
I took the endocrinology section first and had an answer for each of the questions, based on what has been true over the last 2 decades. I then looked on UpToDate, the online resource that is updated constantly by recognized experts in every field, to find whether I had been right, and yes, sometimes I was right. But the answers I found didn't necessarily even correlate with the multiple choice answers, obviously also written by worlds' experts. So on subjects about which it is critical to do the right thing, it is really not clear what that is.
When I graduated from medical school I knew the right answer to questions that were of the ilk where there might be a right answer. Like "Is chemotherapy helpful for pancreatic cancer?" or "What are the most effective antibiotics for a simple urinary tract infection?" At some unclear moment in time, those and many other answers that I knew were no longer correct.
While cruising UpToDate I chanced upon a page called "Practice Changing UpDates" in which I found that a whole bunch of things that we do are wrong. I always feel warm inside when I find out that something that had seemed unnecessarily painful or expensive or complex is of no value. I wonder, though, how soon these new recommendations will also be wrong and when, perhaps, the previous ones will be right again, or whether the whole thing is a huge oversimplification and everything we've ever done was perhaps right, given the appropriate circumstances.
But a larger issue, for me, is the fact that it is now completely impractical to be an expert in the field of medicine, unless perhaps the field of knowledge to which on aspires to have wisdom is itty bitty. Research is just happening so very fast, communication is nearly instantaneous and discussion amongst the many diverse practitioners who very much have a right to their own educated and experienced opinion is limited. For instance: last night I heard another physician tell a patient that he shouldn't drink so much coffee because he was having heart arrhythmias and the coffee would make it worse. He had heard a cardiologist say this and berate another physician for allowing a patient with a heart attack to have a cup of coffee. Studies show that coffee doesn't cause heart arrhythmias and that it is in general good for people in large quantities, reducing risk of liver disease, diabetes and all sorts of realms of misery. But certainly the studies that purport to show that coffee is of no harm and nearly infinite help are not designed to look at this particular individual's risk from caffeine, which definitely can cause an increase in heart rate (check your own pulse after a strong cup if you are not a habitual drinker.) What is true, then, about coffee, or anything else for that matter?
But all that said, I do think the news from UpToDate as of September 20, 2012 is pretty interesting, if not necessarily true.
Of the clinical pearls in the article, 3 stand out as particularly relevant to my practice. First--people with allergy to eggs CAN get a flu shot, even though it is made with eggs, because there is hardly ever any problem. They should be observed for 30 minutes where there are personnel capable of handling an allergy issue after vaccination, but they can go ahead and be vaccinated. The question of how important vaccination is for healthy adults and children is, of course, not addressed, and is still very controversial.
The second is that UpToDate recommends use of Pradaxa (dabigatran), Xarelto (rivaroxaban) or apixaban for prevention of strokes in patients with atrial fibrillation rather than Coumadin (warfarin.) I have written several articles about these new drugs which reduce the ability of the blood to clot and do not require monthly blood test monitoring. They are not easily reversible should abnormal bleeding occur, but honestly neither is warfarin, and the risk of bleeding is so much higher with it because of all of its drug and food interactions and its tendency to be taken wrong. The new drugs are more expensive, but with the expense of monitoring and paying for the morbidity from bleeding or clotting when using warfarin, the costs will end up being similar, and much less once there are generic options. There have been studies looking at various possible risks of the new drugs, including more heart attacks with the use of Pradaxa (dabigatran) but the vast magnitude of error related illness with warfarin dwarfs these risks.
And still. After all of my ranting, I am absolutely positive that many patients will still find that warfarin is the best drug for preventing clotting. There are many people whose doses are always perfect and have absolutely no problems, monitor their own blood tests at home without difficulty and the drug is, in fact, cheap. I could go on with pros and cons for a very long time, but I won't.
I would really like to see these new anticoagulants replace most of the injectable anticoagulants such as enoxaparin and dalteparin since this will profoundly change the way we treat patients with artificial heart valves and blood clotting disorders such as pulmonary embolism.
Last on the "Oh, cool. Finally." list is that it is unnecessary to follow liver function tests for people taking statin drugs such as lipitor (atorvastatin), crestor (rosuvastatin) and simvastatin. They are not liver toxic. We thought they were and they aren't. Again, like with the flu shot, the question of whether so many people should be taking these drugs is begged, but at least they don't need to get blood tests all the time. They also don't need to get their cholesterol levels checked all the time if they are on a dose that is stable and works, but that isn't part of the article, just information from long ago that still hasn't made its way into standard medical practice.