If you have been paying attention to any of the non-Trump-related news this week, you may have noticed headlines about how statin drugs prevent Alzheimer’s disease. Some of the headlines are pretty breathless. The Daily Mail touts “The Pill That Could Stop Millions Getting Dementia;” and Science Daily leads with an even more definitive conclusion: “Cholesterol-Fighting Drugs Lower Risk of Alzheimer’s Disease.” CNN (perhaps chastened by recent events?) is somewhat more circumspect: “Are Statins a Key to Preventing Alzheimer’s disease?”
As a recovering cardiologist, and as an Old Fart who (reluctantly) has been taking a statin drug for several years, I am always on the lookout for new evidence that might convince me that it would be reasonable to stop the drug, or alternately, that it’s really a good thing that I’m taking it. But anyone who wants to learn the objective truth about statins must soon confront the fact that statins are sort of the cardiology world’s equivalent of climate change. That is, a consensus of experts agree that statins substantially reduce the risk of nasty cardiovascular events in people at elevated risk, and that a large majority of people older than 60 should be taking them; but a vocal minority holds statins to be mainly toxins foisted upon an unsuspecting public by people with a special agenda. The debate has become very nasty and vociferous, and we have come to a place where each group tends to simply anathemize the other.
That’s science for you. This is not a new phenomenon; it’s been like this ever since science became a thing. I expect it will remain this way until science is no longer conducted by people.
Anyway, as someone personally affected by the statin debate, I have made a consistent effort for many years to seek objective truth about these drugs. So far, as evidenced by the fact that I continue to swallow one each day, I think that (for people like me at least), the potential benefits probably outweigh the potential risks.
Still, in this long-term effort I have learned never to accept what people say about statins at face value. So when all the news media began barking at me this week that my statin was going to keep me in fine cognitive fettle, I immediately began looking for reasons to disbelieve it. (This is what scientists are supposed to do — to be skeptical of everything.)
In this case it wasn’t hard to find the bulls—t. I simply read the study.
The study was published this week in JAMA Neurology by researchers from the University of Southern California’s Sol Price School of Public Policy.
Note: School of Public Policy. We need to be aware of a couple of things when we consider health-related research produced by public policy experts. First, these are people who don’t take care of patients; they take care of data. Second, they mine the data to come up with stuff they can do to the herd that they believe will improve the average outcome for the herd. Third, they must necessarily assert that mining data is the ultimate pathway to Truth.
Here is what these researchers did: From the vast databases kept by Medicare they took a 20% sample of Medicare beneficiaries, and linked data about enrollment, demographics, vital statistics, and Medicare Parts A, B, and D claims. They identified a group of beneficiaries who had no diagnosis of Alzheimer’s disease, and who had filled at least two statin prescriptions between 2006 and 2012. This produced a sample of 399,979 statin users. They then divided this group into two cohorts according to how many times they filled prescriptions for statins between 2006-2008. The top 50% were said to have high exposure to statins, and the bottom 50% were said to have low exposure to statins. They then assessed which patients were formally diagnosed with Alzheimer’s disease between 2009 and 2013.
They concluded that the “high exposure” statin patients were 10% less likely to develop Alzheimer’s disease than “low exposure” statin patients. Like most public health experts, they chose to report their results as a relative risk reduction (10%) rather than as an absolute risk reduction (which was from about 1.62% to about 1.44%, or a difference of only about 0.18%). This is because when you’re treating the herd, you don’t care that an individual’s odds of a benefit are minuscule, as long as the people managing the herd can measure an appreciable benefit to themselves.
The study went on to further demonstrate the great benefit of data mining as a method of truth-seeking by dividing the 400,000 patients into various subgroups, and attempting to show the differential abilities of particular statin drugs to prevent Alzheimer’s in various genders and races. The more subgroups you look for in these data mining expeditions, the more remarkable things you find. Accordingly they conclude, “The right statin type for the right person at the right time may provide a relatively inexpensive means to lessen the burden of (Alzheimer’s disease).”
Does this study really indicate that statins might reduce the risk of Alzheimer’s? It is possible, I suppose, but if so it’s a fluke. Data mining expeditions in general can be useful in drawing interesting associations, but are useless in determining cause-and-effect. But even to accomplish this much the data mining exercise must be carefully designed so as not to build in predictable bias. This study did not do that.
What do we already know about patients who go to their doctors, accept a prescription for statins (or anything else), and then regularly take the prescribed drug for a period of at least a couple of years? We know that they tend to go to their doctors regularly, and faithfully follow their prescribed medical regimen. If they agree to take statins chronically, we also suspect that they may have at least a modicum of interest in taking personal preventive measures against cardiovascular disease.
What do we know about patients who accept prescriptions for statins and then fill them only very irregularly if at all? Some of them, of course, may have carefully reconsidered the risks and benefits of statins, and reasonably concluded that statins weren’t for them after all. And no doubt that among the 200,000 “low statin exposure” patients there were some like this. But much more likely, many tended to be those people who simply neglect to take their prescribed medication. And if so, it seems reasonable to suppose that they may also have been less likely to follow other important preventive measures, such as not smoking, taking care of their diabetes and hypertension, getting plenty of exercise, and eating a Mediterranean-type diet. All of these lifestyle measures, when not followed, are associated with a higher risk of Alzheimer’s disease. In addition, the “low exposure” group likely included an excess of individuals who, while not yet diagnosed with Alzheimer’s, already had some pre-clinical cognitive decline. Such people often forget to take their medication as prescribed, or to refill their prescriptions.
In my view it seems as likely as not that this study simply divided Medicare patients up into two groups that, from the outset, had slightly different probabilities of developing overt Alzheimer’s disease. The statin prescriptions were merely the mechanism by which these two inherently different groups happened to be identified. It is easy to think of other ways of differentiating these groups that might have been used instead.
Even if this study is accepted at face value as a reasonable hypothesis-generating exercise, it ought to be noted that the hypothesis has already been tested in at least two, published, randomized clinical trials, in which statins were assessed as an Alzheimer’s disease preventive measure. In both trials, statins failed to offer any benefit.
The authors of the JAMA Neurology study were aware of this fact, and argued in their paper that these RTCs were flawed (which is always the case), and that their new analysis offers information that is potentially more compelling than the RTCs. The bottom line is that I find their concluding statement astounding, and so I repeat it: “The right statin type for the right person at the right time may provide a relatively inexpensive means to lessen the burden of (Alzheimer’s disease).”
I will continue to take my statin for now, but this study offers me no comfort. In fact, it gives me some pause that public health experts now seem to be growing in favor of statins for the herd. This is the one thing about this study that seems new to me, and perhaps it is significant.
I’ve posed this riddle before on Ricochet, but I will repeat it here because it makes an important point:
Q: What is the main difference between public health experts and serial killers?
A: Serial killers usually kill only one person at a time.