Saturday, August 27, 2005

The politicization of science

I blogged Wednesday that I thought I smelled politics in the JAMA article on fetal pain and suggested that the authors should have disclosed their political leanings as possible conflicts of interest. Yesterday the Chicago Tribune addressed the issue nicely (thanks to Kevin for directing us to the article).

The author information at the end of the paper says “Financial Disclosures: None reported.” Although no political leanings were disclosed to the JAMA readers one of the authors let her views slip in these comments to the New York Times: Dr. Eleanor A. Drey, one of Dr. Rosen's co-authors, said that as an obstetrician who sometimes performs abortions, she would find it troubling to be compelled to bring up the subject of fetal pain with her patients. "I would be forced to drag them through potentially a lot of misinformation," she said.

We’ve heard howls of indignation about conflict of interest in research until we’re numb, but the outrage has been selective, directed primarily at the financial influence of the pharmaceutical companies. Let’s not forget that political influence and advocacy are also forces that can have corrupting effects on scientific inquiry. Although the JAMA paper may not inform us about fetal pain it will have the beneficial unintended consequence of sparking discussion on an under appreciated form of conflict of interest.

It would be unreasonable to summarily reject a scientific paper based on source or affiliation, be it political or financial. However, disclosure of real or potential conflicts of interest is essential as it gives readers information they need for critical appraisal.

Friday, August 26, 2005

Why study homeopathy----

when it has no physiologic or pharmacologic plausibility in the first place? This is a distortion of evidence based medicine which takes empiricism to an extreme. Straight from the Doc, Medpundit and Medicine and Man have already pointed us to the Lancet article on the subject.

This overview from Homeowatch outlines the field’s history and states that homeopathy was harmless compared to prevailing nineteenth century conventional medical practices, a fact which drove its popularity. It points out the utter irrationality of the theory, which is that a “spirit like essence” remains behind in the water even after all molecules of active substance have been diluted out.

Total lack of biologic plausibility is one reason not to bother to study homeopathy. Another reason, as has already been pointed out by the other bloggers, is that the adherents won’t believe the studies. At least some don’t believe a randomized placebo controlled trial is the proper methodology.

If you want to debunk something, rather than spend all that money on studies, why not just call Randi the magician?

Thursday, August 25, 2005

Fetal Pain

In the latest issue of JAMA is an article about fetal pain which makes the case that abortion providers should not have to inform women about the possibility of procedural pain in the fetus, and purports to back up the assertion with science. Go read what Medpundit has to say about this. She has summed it up better than I can although I would offer a few observations and questions.

The authors’ major premise is that pain is a psychological construct. Indeed, the premise sets the evidentiary standard for the rest of the paper, because, in the authors’ own words, it “presupposes” the neuroanatomic connections they believe must be proven to make the case for fetal pain. Conveniently enough, the presupposition makes tissue injury irrelevant. (What if physicians start telling patients their pain is psychogenic)?

JCAHCO had some things to say about this in its pain management initiative of a few years ago. 1) Patients have a right to assessment and management of pain (implicitly surrogates have the right to be informed about pain). 2) Observation of vital signs, crying and reflex withdrawal (which have been observed in premature infants of less than 29 weeks gestation, and which the JAMA authors seem to dismiss as non-evidence of fetal pain) are legitimate pain assessment tools in preverbal individuals.

The authors admit that the evidence does not establish at what point in fetal development the thalamo-cortical pain pathways become functional.

The first sentence of the abstract establishes the politics driving this “science.” Perhaps the authors’ conflict of interest disclosure should have included their political affiliations. The issue of interface between scientific publication and politics has surfaced previously in JAMA and caused trouble for an editor.

Tuesday, August 23, 2005

Medication safety across the continuum of care

Hospitals have long been concerned about medication errors during the flow of in patient care. Until recently, however, relatively little attention has been paid to the problem of errors at the points of transition between in patient and out patient care. Many hospitalized patients are on a large number of chronic medications. The transition points at admission and discharge are especially vulnerable for such patients because of the need to communicate and document complex medication history. At admission the patient may provide faulty or fragmentary information. At discharge the patient may not understand the doctor’s instructions. Hospitalization often results in one or more changes in the patient’s chronic medication. When medication orders are written in the hospital and when the patient is instructed at discharge these orders and instructions must take into account the patient’s pre-hospital medications and dosages. This is what the Joint Commission on Accreditation of Healthcare Organizations in its 2005 patient safety initiatives terms reconciliation of medications across the continuum of care. This issue was reviewed in an article and an accompanying editorial in the current issue of the American Journal of Health-system Pharmacy. (Open access until September 1 05).

It’s good to see this issue getting the attention it deserves. Accurate transfer of information at the transition of care seems to be an elusive quality goal. Deficiencies in the process are what we hospitalists often refer to as the “information voltage drop.”

Thursday, August 18, 2005

More about evidence based patient decisions

I blogged about this recently. Among other things I pointed out that an essential component of evidence based medicine (EBM) was involvement of the patient in the decision process by providing quality information. Although this important step is often ignored in discussions of EBM it was emphasized as a defining characteristic in the classic paper of David Sackett entitled “Evidence based medicine: what it is and what it isn’t.” The authors state that the process, among other things, involves “------the more thoughtful identification and compassionate use of individual patients' predicaments, rights, and preferences in making clinical decisions about their care.”

I discussed the concept of number needed to treat (NNT) as an understandable way to discuss the magnitude of treatment effects with patients. Then I ran across this recent study. It seems patients have difficulty with the concept. Decisions were influenced only marginally, if at all, by the NNT. In addition, 24% of patients who made a decision after being informed of the NNT changed their minds following additional explanation of the meaning of NNT. In almost all cases better understanding of the concept caused patients to reject the treatment in question. Worse, this paper from the August 1 issue of American Family Physician paints a dim picture of patients’ health literacy.

This is sobering. In my previous post I illustrated that the process was time consuming and challenging. These papers suggest that it’s even more challenging than we had thought.

Monday, August 15, 2005

Diagnosis of pulmonary embolism: Are we there yet?

A systematic review in the April 27 issue of JAMA was blogged about by Inner Visions on May 8, and has more recently been given the status of POEM as abstracted in the current issue of Cleveland Clinic Journal of Medicine. The take home message was that a normal CT done with the appropriate technique equals pulmonary angiography (PAG) for the exclusion of pulmonary embolism (PE). This sounds simple enough, but questions remain about how this evidence changes our diagnostic approach. What is the initial test of choice? Does CT replace nuclear ventilation and perfusion (V/Q) scanning?

This paper doesn’t answer these questions. Such questions require a broader perspective which takes into account the results of PIOPED I and PIOPED II. The JAMA review evaluated the performance of CT by the standard of freedom from events over three month follow up and compared those results with similar data previously reported for PAG. PIOPED I evaluated V/Q scanning against the reference standard of PAG. PIOPED II evaluated CT against a multi-dimensional diagnostic strategy using non invasive tests and occasional use of PAG. The multi-dimensional strategy was validated as a reference standard by clinical follow up for freedom from events. PIOPED II has not been published, but its results were presented at the Radiological Society of North America 90th Scientific Assembly and Annual Meeting late last year, abstracted here at Medscape (free registration required).

While consideration of all this evidence together with cost and patient tolerability provides no simple answers, I believe the following statements are supported.

1) Invasive PAG is seldom indicated.
2) A normal V/Q scan has the best negative predictive value (NPV) of all tests (note I said normal, not “low probability”). (In PIOPED I no patients with normal V/Q had PE!).
3) When CT results are discordant with clinical probability the PPV and NPV are poor. This was a significant finding in PIOPED II, similar to the findings for discordant V/Q results in PIOPED I. This means that, just as with V/Q scanning, results of CT must be integrated with other clinical data.
4) A CT scan costs more than a V/Q scan. [1].
5) There is no clear modality of choice for initial testing. Careful clinical assessment determines the choice of the initial test(s) which might include D-dimer, leg compression ultrasonography, V/Q scanning or CT.

This POEM adds to our knowledge of testing for PE but it’s just one piece of the puzzle. Be careful of simplistic interpretations.

Thursday, August 11, 2005

Who has time for evidence based medicine?

I recently blogged an ideal description of evidence based medicine. I gave examples to point out that it’s onerous, and I implicitly questioned whether it’s realistic. Truth be told I wonder if many doctors even practice it. A commenter did a better job of making the point. “My goodness. If my physician went to all that trouble for me, I'd require resuscitation from the shock. But to tell you the truth, such extreme conscientiousness -- while I applaud it -- is not only impractical in terms of time (yours!) but also overestimates by a long shot what most patients would expect in terms of empowerment.” (Go read the comment in its entirety).

EBM is indeed rigorous. Formulating a question, translating the question into a search strategy, performing the search and critically appraising what you retrieve is a substantial chore even with the help of the short cuts provided by some medical Internet resources. Of course, your job isn’t finished there. You then must evaluate how well the patient populations represented in the evidence you’ve retrieved match the unique characteristics of your patient and, finally, integrate this evidence with your patient’s preferences, circumstances and values.

Most of us would say we practice EBM but the reality is we often practice only the trappings of EBM. That is, we can quote from randomized controlled trials and talk about meta-analyses, odds ratios and confidence intervals. We can name off a number of things doctors who practice EBM are supposed to do, and to a variable degree, do them. We use Internet resources but often not in a systematic way. With good intentions we put on these appearances and often still don’t really practice EBM as we’re supposed to.

What we have then is a degree of disconnect between the theory and the practice of a revolutionary idea in medicine. This is not unprecedented. It is analogous to another revolution in medical thinking that occurred in the 1960s: the problem oriented medical record, a.k.a. the Weed system. It was the talk of the wards when I was a medical student. Since those days SOAP formatted progress notes have become commonplace, and most medical records have had a problem list, after a fashion. However, this is a far cry from the true practice of the Weed system as it was originally defined and taught. Again, we practiced only the trappings. (In researching for this post I was unable to find any of the original descriptions of the Weed system to provide as links. The articles are old and only the citations are on line. I was able to find a print description in an old copy of Hurst’s The Heart, sixth ed., which contains a description on p. 105. J. Willis Hurst, professor and chairman of the Department of Medicine at Emory, was a champion for the Weed system [1] [2]. Older editions of his text contain elegant descriptions of the problem oriented medical record as applied to clinical practice, which time and space constraints do not permit me to abstract here).

We miss the mark with EBM, in part because we lack time. Reimbursement incentives put doctors under pressure to see large numbers of patients in limited time, and consequently don’t reward the practice of EBM. How then should we regard it? We should embrace it. If the ideal is unattainable it should challenge, not discourage us. It is a challenge I find fascinating, and one that I approach with the hope that as we ascend the learning curve and information resources improve, things will get better and better.

EBM has many dimensions which fascinate me, and I’ll be blogging about it a great deal. Stay tuned.

Friday, August 05, 2005

How and why do doctors read?

It occurs to me that the ways we read medical literature fall into at least two categories. First there’s the type of reading we do to practice evidence based medicine (EBM). That type of reading focuses on the clinical question at hand as it applies to a particular patient. We often use the PICO acronym to help us formulate the question. (In a Population with my patient’s attributes, what is the effect of the Intervention in question versus a Comparison group with respect to Outcomes?). Such a question forms the basis for a search that will retrieve relevant articles. This highly focused and specific type of reading has been variously termed question driven reading, problem based reading and foreground question reading, and often relies on POEMs. It is often done “at the point of care”, e.g. the physician’s office, the exam room or the hospital ward. The reading material might consist of abstracts of randomized controlled trials, a systematic review, or topic summaries from a filtered source such as Bandolier, DARE, TRIP, or Up to Date. This is a relatively new type of reading, not possible before the availability of the Internet and the vast repository of searchable medical databases.

Another type of reading is the more traditional type which, although often patient based, is not as focused. It is sometimes referred to as
background question reading. I have recently heard the somewhat derogatory term “reading for the heck of it” to describe this type of reading. Such reading often draws on DOE (disease oriented evidence). It is more likely to take place at home, and the topic might be related to a patient you saw that day, or that week. The source could be a textbook or a narrative review. It would have a broader scope than the former type of reading, and might encompass the clinical features, epidemiology and pathophysiology of a disease.

So why do I make a fuss about this? Well, it seems there’s a ground swell of opinion these days against background reading.
This article encourages students to do problem based searching of filtered resources, but not to bother with standard medical journals! This tutorial on EBM warns the reader that DOE is worthless if not dangerous. I’m reading more and more opinions of this sort, many taking aim against narrative reviews, textbooks, experts and the practice of reading about pathophysiology. The purveyors are purportedly doing this to advance the cause of EBM. I would argue that this reflects a narrow view of EBM. The classic paper by Sackett, et. al., which many recognize as a defining article on EBM, clearly points out that expertise and judgment (which I believe derive from background reading) are important components of the process.

I believe both types of reading are essential. Without foreground reading we can’t bring the best and most current evidence to bear on the individual patient’s problem. Without background reading we lack depth of understanding, and can never cultivate the expertise and judgment so essential to the rational and prudent application of evidence.

Now excuse me while I go read a chapter from Harrison’s.

Tuesday, August 02, 2005

Do drug company promotions impact clinical outcomes? Is there a way to know? Does anybody want to know?

My recent post on the effects of drug industry marketing drew a difficult and insightful question: “RW, how do you propose to measure patient outcomes?”
Can outcome based research be done, or must surrogate evidence suffice? Perhaps patient outcomes in a health care setting (a clinic, an academic medical service, an HMO, or a hospital) could be measured before and after implementation of a “no sample” or a “no drug rep” policy. Is there precedent for this type of study? Yes. There are numerous examples of health system, health care environment, and cultural changes that have been studied for their effects on outcomes including the adoption of heart failure multidisciplinary management programs [2]