Category Archives: medical literature issues

Am I missing something?

The cover of this week’s Lancet, in bold: “No doctor should be practicing, even after that single glass of cold Chardonnay”.

This refers to a brief editorial on the topic, “Just one before the scalpel“. In that editorial, the Lancet states:

“The individual response to alcohol varies greatly, depending on sex, body size, eating food, taking other drugs (eg, antihistamines), and the complexity of the impending task. Because of the unpredictability of the response, no alcohol in the blood when on call must become the norm. Indeed, other professions face that stricture. For example, UK pilots are not meant to fly for at least 8 h after drinking even small amounts. US pilots face stricter rules: no drinking within 8 h of take-off.”

Now let’s see. No drinking within 8h of take-off is stricter than not flying for at least 8h after drinking. Am I missing something? Or have the proof-readers at the Lancet been sneaking off to their local pub?

EBM and industry

This week’s BMJ is a theme-based issue on Evidence-Based Medicine. It contains the expected articles on how to judge whether or not EBM is living up to its promise, how best to implement it, and so on. There is one aspect of EBM, however, that is not addressed: its effect on the drug and device industries.

An implicit subtext of the evidence-based movement is that it helps counter the millions of dollars of industry propaganda and hype that wash over us every year. And EBM does, indeed, provide tools to judge drugs and interventions more objectively than we think the industry would like us to. But the drug and device industries have evolved along with (or ahead of) their customers.

Pharmaceutical companies have responded to EBM by carefully designing trials destined to apply to as wide a population as possible, while still obtaining (p<0.05) benefit. Then, armies of drug reps sally forth armed with reprints, while researchers are sent out to spread the gospel of statistical significance. EBM has made us particularly avid of hard data (while relegating clinical significance to a somewhat subordinate role). This emphasis on statistically significant data has been digested by industry and is now used to sell drugs and devices.

Evidence is good. Evidence-based methodologies are better. But they aren’t magic bullets. And EBM is a tool whose use is not restricted to pure and virtuous clinicians. Caveat lector.

Endovascular repair of abdominal aortic aneurysms

An article in the October 14, 2004 New England Journal of Medicine reports on the results of the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial, which compares endovascular abdominal aortic aneurysm repair with open surgical repair. 345 patients with AAA of at least 5 cm in diameter and who were eligible for both endovascular and open approaches were randomized. In the short term, the endovascular approach yielded lower peri-operative mortality (1.2% vs. 4.6%) and lower peri-operative mortality plus severe complications (4.7% vs 9.8%). The numbers did not quite reach statistical significance, but are convincing and in line with a second, similar, recently published study from England.

An important note of caution is sounded, however, in an editorial by F. Lederle. He does not dispute the short term results, but suggests that the long term results remain in question, and require longer follow-up of these trials. He notes that two European registries have reported a higher annual failure rate (3% vs. 0.3%) for endovascular repair compared to surgery. Lederle also mentions an article about the problem of late graft failure that was initially accepted for publication by the Journal of Vascular Surgery and then suppressed after industry pressure.

An editorial describing this matter in the August, 2004 Journal of Vascular Surgery is very enlightening. It describes how the article in question, based on data on the Medtronic AVE Aneurx stent graft system and written by four authors from the FDA, was submitted to the Journal of Vascular Surgery in December, 2003 and accepted for publication in March, 2004. This article was based on data that the FDA had made public on December 17, 2003, in a Public Health Notification, concerning aneurysm-related mortality rates.

According to the editorial, in May, 2004, Medtronic threatened legal action if the article was published because it supposedly revealed confidential data; the FDA then requested that the article be withdrawn because “the conclusions drawn in the article went beyond the information provided in the Public Health Notification and, therefore, did not reflect the FDAs current position regarding AneuRx related mortality.”

The authors of the Journal of Vascular Surgery editorial clearly do not believe that the confidentiality issues invoked by Medtronic were valid, and believe that the article’s conclusions are within the bounds of reasonable scientific discussion. They encourage readers to make themselves aware of the data that is available at the FDA website. There are some more comments on this issue in the Letters to the Editor of the following month’s (September) Journal of Vascular Surgery.

This controversy was also publicized in a long front-page article in the July 9, Wall Street Journal, which is not freely available online.

I would encourage readers interested in endovascular approaches to abdominal aortic aneurysms to take a look at the above references.