Editor’s Note: The following guest post by Dr. David Newman is reprinted with permission from his website and blog, Smartem.Org. Dr. Newman is an Emergency Physician and Director of Clinical Research at Mt. Sinai School of Medicine in the Department of Emergency Medicine. He is the author of the critically-acclaimed Hippocrates’ Shadow: Secrets From the House of Medicine. CardioBrief readers might also enjoy watching his TED talk, Truth That Lasts.
Data, Drugs, And Deception– A True Story
by Dr. David Newman
Last week The Lancet published a meta-analysis of 27 statin trials, an attempt to determine whether patients with no history of heart problems benefit from the drugs — true story. The topic is controversial, and no less than six conflicting meta-analyses have been performed — also a true story. But last week’s study claims to show, once and for all, that for these very low risk patients, statins save lives — true story.
Actual true story: the conclusions of this study are neither novel nor valid.
The Lancet meta-analysis, authored by the Cholesterol Treatment Trialists group, examines individual patient data from 27 statin studies. Their findings disagree with an analysis published in 2010 in theArchives of Internal Medicine, and with analyses from two equally respected publications, theTherapeutics Letter and the Cochrane Collaboration.* Despite this history of dueling data the authors of last week’s meta-analysis, in a remarkable break from scientific decorum, conclude their report with a directive for the writers of statin guidelines: the drugs should be broadly recommended based on the new analysis.
As an editorialist points out, if implemented, the CTT group recommendations in the United States would lead to 64 million people, more than half of the population over the age of 35, being started on statin therapy — true story.
Where is the magic, you ask, in this latest effort? What is different? In some ways, nothing. Indeed just a year and a half earlier The Lancet published a meta-analysis of 26 of the same 27 studies, with the same results, by the same authors (true story, and an odd choice on the part of the journal). So the findings aren’t new. They are, however, at odds with other meta-analyses. Why? It is the way they calculated their numbers. This meta-analysis, like the earlier one from the same group, reports outcomes per-cholesterol-reduction. The unit they use is a “1 mmol/L reduction in low density lipoprotein (LDL)”, in common U.S. terms, a roughly 40-point drop in LDL.
That’s the magic: each of the benefits reported in the paper refers to patients with a 40-point cholesterol drop. Voilá. One can immediately see why these numbers would look different than numbers from reviews that asked a more basic question: did people who took statins die less often than people taking a placebo? (The only important question.) Instead, they shifted the data so that their numbers corresponded precisely to patients whose cholesterol responded perfectly.
Patients whose cholesterol drops 40 points are different than others, and not just because their body had an ideal response to the drug. They may also be taking the drug more regularly, and more motivated. Or they may be exercising more, or eating right, and more health conscious than other patients. So it should be no surprise that this analysis comes up with different numbers than a simple comparison of statins versus placebo pills. Ultimately, then, this new information tells us little or nothing about the benefits someone might expect if they take a statin. Instead it tells us the average benefits among those who had a 40-point drop in LDL.
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