This release points to a novel strategy for targeting some of the pathology associated with Alzheimer’s disease that is newsworthy and deserves attention. The study that it describes shows that certain drugs may inhibit a key enzyme that contributes to Alzheimer’s plaque buildup in the brain — and that patients who took these drugs to prevent transplanted organ rejection had lower rates of Alzheimer’s disease compared with people who didn’t take these drugs. But the release’s overly enthusiastic tone may generate more than attention — it could engender false hope. The findings are interesting but preliminary, and the study’s retrospective, observational design has a number of limitations that deserved comment.
Alzheimer’s disease and associated dementias are terrible diseases with no adequate treatments and no clear preventive strategies. As a result, people with the diseases and their families are appropriately interested in new treatments and preventive measures. That’s why it’s so important to get the information to the public in a balanced manner.
The economic and clinical toll taken by Alzheimer’s and other forms of dementia is staggering, so a treatment that could reduce the likelihood of developing the disease would have large consequences. Identifying who should receive the treatment is important since not everyone will develop dementia. That makes the cost of the intervention an issue from the economic perspective. These are difficult issues to explore in a new release, but the release could have at least signaled the importance of the discussion by mentioning the cost of these drugs. The medications are currently available for use by transplant patients — so pricing should not be hard to find.
We’ll reward the news release here for providing data taken from the published study that quantities the benefits. It helpfully gives the absolute rates of dementia in those taking the drugs and in the general population. That makes the numbers easy to understand and gives an accurate sense of the size of the effect. Having said that, however, the language used in the title and the comments from the senior author go beyond what the study is capable of determining. We’ll discuss that shortcoming below under the “Evidence” criterion.
The news release does point out that preventive treatment with anti-rejection drugs suppresses the immune system. But exactly what does that mean? What are the implications of this effect? The release does not provide any description of the potential problems that could occur. And that is not the only issue with these drugs. Both tacrolimus and cyclosporine have an extensive its of side effects.
On the plus side, the news release does provide a good discussion of the important aspects of the study noting the previous animal studies, the underlying theory of why these drugs might work and the nature of the study design and actual data. However, the news release does not point out the obvious limitations of a retrospective observational study. And the language used in the headline and by the investigators implies a strength to the findings that isn’t appropriate: “Anti-rejection medications for transplant recipients protect against Alzheimer’s disease”. Based on that headline, readers will clearly infer that this is a cause-and-effect relationship, when the design of this study can’t support such a conclusion. These drugs are “associated with reduced risk,” but it’s too soon to tell if they “protect.”
No disease mongering here.
The funding sources are clearly identified. The authors disclosed no conflicts of interest in the paper, a fact which the news release could also have shared with readers.
The Alzheimer’s association lists a host of strategies that may lower risk of developing dementia. These include exercise, socialization, blood pressure control and the like. In addition, there is an ongoing randomized clinical trial of anti-amyloid drugs in high risk patients.
Although not explicitly stated, it is clear that the drugs in question are available. That raises a possible concern, as their availability and the news release’s enthusiasm may result in patient demand for access to this as-yet unproven strategy.
The story described previous animal research leading up to the current study in humans. And the findings from the study are interesting and novel. Given that these drugs have been used for decades, at least in the case of cyclosporine, it’s surprising that this effect hasn’t been noted before — all the more reason the finding needs replicating and examination with a stronger study design.
The news release is a bit too enthusiastic about the results of this retrospective observational study. One of the authors says the data “support, for the first time in human subjects, our notion that calcineurin inhibition has a protective effect on the development and possible progression and even reversal of Alzheimer’s disease.” Certainly “reversal” is beyond the pale. The release’s repeated claims that these drugs “protect” against Alzheimer’s is also not justified based on the evidence.