Saturday, August 30, 2014

Management of intracerebral hemorrhage following TPA for ischemic stroke

If there are any effective reversal treatments there is no good evidence to guide their use according to a systematic review in JAMA Neurology.

A discussion of the paper in Medpage Today notes the need for better evidence. The discussion says guidelines address the problem of TPA related cerebral hemorrhage, though based on low level evidence and expert opinion. The piece links to the current guidelines for the management of ischemic stroke. Those guidelines, however, only briefly mention TPA related hemorrhage and for management of this complication refer the reader to these guidelines for management of cerebral hemorrhage. They in turn, however, do not specifically address TPA related hemorrhage though they do address head bleeds related to oral antithrombotic agents.

Friday, August 29, 2014

Clinical trials to see if nutty ideas work

Don't laugh, because our tax money has been paying for such “research” for years. A recent paper outlines a little of the history, gives some examples and calls for it to stop.

From the opening of the paper:

A new phenomenon in clinical trials has arisen over the past 20 years. Complementary and alternative medicine (CAM) or integrative medicine (IM) modalities based on principles that bespeak infinitesimally low prior probability of success or that even violate well-established laws of physics and chemistry are being tested in randomized clinical trials (RCTs). CAM proponents frequently justify such RCTs by arguing that they will finally settle once and for all which CAM or IM modalities do and do not work. Our response is that this is a misguided viewpoint that has led to the infiltration of pseudoscience in academic medicine.

The authors give some examples which illustrate the absurdity of what's going on, then move to a discussion of the role of evidence based medicine, stating:

Evidence-based medicine (EBM) assumes that treatments do not reach the stage of RCTs without having amassed sufficient preclinical evidence to justify the effort, time, and expense of RCTs, as well as the use of human subjects.

Indeed that must have been the assumption of the founders of EBM in 1992 when the movement was launched. It must never have occurred to them that nutty ideas would someday be the subject of clinical trials. Hence the processes of EBM had no formal mechanism to distinguish sense from nonsense. Who knew, early in the movement, that such a mechanism would be needed? But, as illustrated in the paper, the assumption proved to be naïve thus exposing a major failure of EBM. I addressed that failure here and in several other posts.

Doing clinical trials to study implausible claims appears to be a violation of the Declaration of Helsinki, as the authors point out:

Indeed, so integral to this process is biological plausibility based on preclinical data that the Declaration of Helsinki [8] states, ‘medical research involving human subjects must conform to generally accepted scientific principles, be based on a thorough knowledge of the scientific literature, other relevant sources of information, and adequate laboratory and, as appropriate, animal experimentation’.

The full text of the paper is available for free and is worth reading in its entirety for all the richness there.

Thursday, August 28, 2014

Dean Ornish on lifestyle medicine

The idea behind lifestyle medicine, that a multifaceted program of hygienic (non pharmacologic) measures can help prevent or even treat many chronic diseases, though not new, continues to gain traction. It's an area of great interest to me and recently Dean Ornish's piece in Medpage Today caught my eye. From the post:

We tend to think of advances in medicine as a new drug, laser, or surgical device, something high-tech and expensive. Yet, the simple choices we make in what we eat and how we live have a powerful influence on our health and well-being.

True as that may be there are questions that need to be addressed about the science behind lifestyle medicine. First, lifestyle medicine represents a bundle of interventions. There are many bundles in medicine. If a bundle is proven to work we still may not know about the efficacy of its individual components until we study them individually. Some components may even prove to be harmful. A very recent example of this was the unbundling of early goal directed therapy. We'll never succeed in unbundling something so complex as lifestyle, yet we need to learn more about which of its individual components are most helpful and which ones are not so helpful or even harmful.

In the case of Ornish, a good deal of his work is beset with small numbers, methodologic issues and questionable assumptions. Despite these concerns I read his post with great enthusiasm until I came to this stopping point:

These lifestyle changes include:
A whole foods, plant-based diet (naturally low in fat and sugar)
stress management techniques (including yoga and meditation)

Hmmm, so yoga is part of the Ornish bundle. But this takes us way beyond scientific concerns about bundling into a whole new arena. Yoga is a complex philosophical and religious system that makes certain supernatural claims. If Ornish had merely mentioned its material aspects (stress management, low impact exercise, etc) without mentioning yoga itself my reaction would have been different. But to promote yoga as a specific system with benefits beyond the generic effects of exercise and relaxation, as Steve Novella once pointed out, implies magic. When magic is mixed with science you get pseudoscience. Apparently Ornish's interest in the magic arts doesn't stop with yoga.

Wednesday, August 27, 2014

A new wave in the uprising against maintenance of certification (MOC)

R. Mack Harrell, MD, president of the American Association of Clinical Endocrinologists (AACE), told Medpage Today that MOC in its present form must change and the status quo will not be tolerated. He and other internal medicine leaders attended an internal medicine summit last month in which they outlined their objections to the American Board of Internal Medicine (ABIM). A leader of the ABIM who was present said he'd take it back to the board. According to Dr. Harrell multiple subspecialty leaders are aligned with this effort and if a satisfactory answer is not forthcoming from the board they will begin work to develop alternative means to recognize doctors' efforts in lifelong learning.  

New York Times piece on Pradaxa (dabigatran)

It seems the folks at BMJ think they've uncovered a scandal in the approval and launch of Pradaxa. (What they actually “uncovered” was nothing of the sort although some bloggers have piled on with the idea). Based in part on the BMJ report the NYT ran a piece about the risks of Pradaxa. Dr. John M then gave the NYT article a nice smack down:

This purpose of this post is to clarify misstatements made in a recent New York Times article about the anticoagulant drug dabigatran (Pradaxa). The piece had three major inaccuracies, plus one thought-error from a cardiology leader.

I encourage you to read the rest of Dr. John's post for specific examples. This sort of thing is not unusual for NYT reporting on medicine nor is it unique to them. There's a problem that arises when a journalist tries to present a scientific topic to the general public: it gets dumbed down. Way, way down sometimes, for several reasons. Often journalists uncritically accept and run with popular myths (in the case in question, the myth that patients taking warfarin cannot eat certain green vegetables). Sometimes they gloss over important distinctions (in the case of the NYT piece the author either didn't know, or didn't care about the difference between relative risk and absolute risk). Perhaps most importantly scientific topics, when reported with the nuance and subtlety they deserve, lose a lot of their value as a “story.” This last reason, though no excuse for sloppy reporting, is a common. To report on medicine to the lay public is to take something that's arcane, tentative and sometimes ambiguous and make it interesting. It can be done but few journalists seem to take the effort required to pull it off well.

Sunday, August 24, 2014

On role modeling

In a really interesting read in the journal Academic Medicine Dr. Jochanan Benbassat explains that role modeling, though vaguely defined and part of the “hidden curriculum,” is a powerful factor in medical education. We are well aware of its good aspects; we seek to emulate the traits of mentors we admire. But there are unintended consequences, says the author. The responses to role modeling are largely subconscious, somewhat emotionally driven, uncritical and even primitive. There are potential dangers. My own take is that the student's response to the role model involves the psychological defense mechanisms of identification and introjection. Early in the process of finding out who they are and what they are becoming as clinicians, students are uniquely susceptible. (These psychological mechanisms were explored with fascinating insight and great comical effect in Woody Allen's movie Zelig). The article explores ways students can mitigate the harmful effects through self reflection and critical thinking.