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Implantable device ‘aids weight loss’? Let’s wait for the evidence

Tiny implantable device short-circuits hunger pangs, aids weight loss

Our Review Summary

implantable device for weight loss

UW-Madison graduate student Guang Yao (left) and Xudong Wang (right) hold a small implantable device for weight loss

This release about an experimental implanted device to promote weight loss tells readers that it has been tested only in rats (though not until the third paragraph), but then it goes on to proclaim that the new device has “several advantages” over an existing FDA-approved device that also works by stimulating the vagus nerve to alter hunger perception, despite the fact that these comparative claims have not been tested. The release implies that the device could help all people who have obesity, without noting that the existing device is restricted to a subset of people.

The release makes claims of benefits that have yet to be tested and does not mention harms that similar devices cause. The study was published in Nature Communications.


Why This Matters

The history of medical research is littered with “successful” animal experiments that failed to produce useful human treatments. While animal experiments that support a novel concept may be of general interest, this experimental device appears to be a refinement of an existing type of device. In this case then, the story is not the underlying concept, but whether this new device is better or worse than the existing one. Until the two are compared directly, no one can say (and news releases should not claim) that they expect a device tested only in some rats will prove to be superior to an approved device or other alternatives. Let’s wait for the evidence.


Does the news release adequately discuss the costs of the intervention?

Not Satisfactory

Although this device is still in early testing, the news release notes that it is intended to improve upon a similar device that is already available. The procedure to implant the existing device may cost more than $20,000. This release could have told readers what the current price range is for such a device. If the researchers have reason to expect their device to be more or less expensive than the existing device, that information should be included.

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

The news release refers to “several advantages over an existing unit that stimulates the vagus nerve for weight loss;” however, since this device has yet to be tested in human subjects, it is too early to claim that it offers benefits greater than the FDA-approved device. What’s more, while the release states that rats in this trial lost almost 40% of their body weight, studies of the existing weight loss device say people lost less than 10 percent of their body weight, and that was when they were in a program that included diet and exercise counseling. These important caveats should have been included.

Does the news release adequately explain/quantify the harms of the intervention?

Not Satisfactory

The release does not discuss potential harms, even though the similar, approved device has caused a number of harms, such as:

“Nausea, pain at the neuroregulator site, vomiting and surgical complications were among the serious adverse events reported in the clinical trial. Additionally, some patients experienced pain, heartburn, problems swallowing, belching, mild nausea and chest pain.”

The release should have addressed the possibility that this experimental device could present similar risks.

Does the news release seem to grasp the quality of the evidence?


We will give the release a satisfactory rating on this criterion because it clearly notes that the trial was done in rats and that further tests in larger animals, followed by human clinical trials, have yet to be done. However, news releases about animal trials should point out that the vast majority of “successful” animal trials fail to ultimately lead to clinical treatments in people. (See our toolkit for more reasons why you should be cautious of health claims based on animal and lab studies.)

Does the news release commit disease-mongering?

Not Satisfactory

The lead sentence of the release proclaims that more than 700 million adults and children worldwide have obesity. However, many people who are obese are not considered candidates for treatment with this type of weight loss device. Obesity is defined as a Body Mass Index greater than 30. The existing similar device is approved only for certain patients with a BMI greater than 35 or 40, depending on other health factors and previous treatment. In other words, the release overstates the number of people who might be candidates for receiving this experimental device, if it ever comes to market.

Does the news release identify funding sources & disclose conflicts of interest?


The release states that funding was provided by grants from the National Institutes of Health. It’s noteworthy that the journal article reporting the trial results states the authors declared no competing interests. However, the release discloses that the researchers patented the device. This is a glimpse at the varying and incomplete ways in which conflicts of interest are (or are not) reported in journals and in downstream news coverage.

Does the news release compare the new approach with existing alternatives?


The release does report that there is an existing FDA-approved device for weight loss that uses a similar vagus nerve stimulation method. However, as mentioned above, the release improperly makes claims of superiority that have yet to be tested.

Besides implantable devices there are, of course, a whole hosts of non-invasive means of losing weight, including the newer drug liraglutide which may lead to losses greater than those seen with implantable devices.

Does the news release establish the availability of the treatment/test/product/procedure?


The release states that the device is experimental, and that further animal and human testing lie ahead.

Does the news release establish the true novelty of the approach?

Not Satisfactory

The release says this device could be an improvement on an approved device that also stimulates the vagus nerve to alter hunger perception. It states that what is new is that the experimental device uses motion of the stomach, rather than batteries, to produce electrical pulses that stimulate the vagus nerve. It also claims that the pulse patterns are superior because they are triggered by stomach motion; however, since the new device has not been compared to the existing model, it is too early to make this claim.

Does the news release include unjustifiable, sensational language, including in the quotes of researchers?

Not Satisfactory

By definition, researchers do not know whether an experimental device is better or worse than existing devices or other alternatives, so the release should not have included quotes that jump to conclusions, such as, “Our expectation is that the device will be more effective and convenient to use than other technologies” or that the stomach-motion trigger is superior to the control method of the existing vagus nerve stimulator, since the methods have not been compared.

Total Score: 4 of 10 Satisfactory


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