Monday, December 16, 2013

More on Cholesterol Guidelines: Cochrane Lets Us Down

Dr. Roy Poses over at Health Care Renewal did a nice post on the cholesterol guidelines—
--that have been the subject of my two previous posts:

The basic question, you’ll recall, is: how did we end up with supposedly “evidence-based” guidelines that read like a script written by the drug industry to sell statins, when the most accurate and dispassionate reading of the actual scientific literature arguably tells us that 1) statins are way overrated as a way to prevent heart disease and 2) that to the extent that statins do work, it’s not at all clear that they work by reducing cholesterol levels?

Well, one way this happened is that a couple of meta-analyses (which don’t do any new research but rather re-evaluate studies previously conducted) which come from supposedly neutral and respectable sources have recently set up a big cheer for statins as effective primary prevention (prevention for people who don’t yet have established cardiovascular disease). One is the CTT that we’ve already gone over in some detail, for instance:

The other is a recent review from the Cochrane Collaboration. This organization is supposed to be the world’s gold standard for evidence-based systematic reviews. I tell medical students that they should generally look first to Cochrane if they want reliable evidence as to how well any medical treatment works. But for all the great work Cochrane does, and their generally impeccable results, they occasionally slip up, and some reviews have been discovered in the past to have been done by people with unreported conflicts of interest.

The review of statins for cholesterol seems to be one of their flops. Dr. Poses’ post, above, provides details as to why the methods used in their review are questionable. It has also been reported that at least one Cochrane review author had financial ties to the drug industry.

This has not stopped the pro-statin crowd from running with Cochrane as their main evidence for how wonderful statins are. Last week’s JAMA featured an editorial (subscription probably required) “Accumulating Evidence for Statins in Primary Prevention,” by an author who lists about a dozen financial ties to drug-makers. The editorial and the article on which it comments both rely heavily on the Cochrane review as their evidentiary centerpiece.

Normally, when pharmaceutical marketing reaches the level of “irrational exuberance,” we can depend on Cochrane to rein in the excess enthusiasm. It is very sad to see Cochrane instead pouring gasoline on the fire.

Robinson JG. “Accumulating Evidence for Statins in Primary Prevention.” JAMA 310: 2405-6, Dec. 11, 2013.

ADDENDUM 12/20/13: I have been waiting for some backup on the cholesterol guidelines issue from people who actually have the expertise to crunch the numbers. Here's a reply by our old friend Dr. John Abramson (Overdo$ed America) to a response offered to an earlier opinion piece that he co-authored, by the authors of the Cochrane review mentioned above. The reply further develops some of the criticisms of the Cochrane review.

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