Back in December, I wrote a blog post which focused on the habit drug companies have of causing the medical profession and the public at large to forget what medicine is for . The point I made is that much of medical research is not focused on health itself, but what are known as ‘surrogate’ outcomes or ‘end-points’ such as blood pressure, cholesterol levels or blood sugar levels. In this blog, I gave examples of some conventional treatments that might help surrogate end-points, but don’t seem to do much for us in real terms. Sometimes, the treatment might be downright dangerous.
This week saw the publication of a study which is another example of why it’s important to look more deeply into the reported results of a trial. It concerns research published in the Journal of the American Medical Association reporting on the results of what is known as the ‘METEOR’ trial. In this study, the effects of the cholesterol-lowering drug rosuvastatin (Crestor) in healthy middle aged individuals, some of whom had evidence of fatty build-up (atherosclerosis) in one or both carotid arteries (the main vessels supplying blood to the brain).
Compared with placebo (inactive medication), treatment with rosuvastatin over two years reduced cholesterol levels, and also halted the progression of atherosclerosis. This all looks good on the surface of it. And not surprisingly, the publication of these results got a lot of press around the World and I’m sure made rosuvastitin’s manufacturer, AstraZeneca, very happy.
But let us not lose sight of the fact that the main outcomes this study was designed to assess (cholesterol levels and atherosclerosis) are surrogate end-points. They do not measure the effect of rosuvastatin on so-called ‘cardiovascular’ events such as heart attacks. The whole point of reducing cholesterol, we are told, is to prevent such events, after all.
What this study showed was that in the placebo group, no individuals suffered a serious adverse cardiovascular event. On the other hand, 6 individuals in the rosuvastatin group suffered a total of 8 serious adverse cardiovascular events (including heart attack and angina). Admittedly, the serious adverse effect rates in the treated group were low. But there’s no getting away from the fact that when we look at these outcomes (rather than the surrogate end-points the study was designed to examine), then the results of the METEOR trial don’t look as stellar as the press reports make them out to be.
2. Crouse JR, et al. Effect of rosuvastatin on progression of carotid intima-media thickness in low-risk individuals with subclinical atherosclerosis: The METEOR Trial.JAMA 2007; March 25 [Epub ahead of print]