Wearable monitors: what do we really know?

michael joynerThe following guest post is by Dr. Michael Joyner, a medical researcher at the Mayo Clinic. These views are his own. You can follow him on twitter @DrMJoyner.

One of the most interesting pieces of health care reporting I have read in the last couple of weeks was Charles Piller’s article in Stat on leadership issues at Verily, Google’s effort to “transform” medicine.  As you might be aware, Google has bet that a combination of gene sequencing, biomarkers, intensive monitoring, and big data will give individuals the information they need to stay healthy and/or intervene early and effectively in many diseases. Verily has a slick promotional video touting this vision and the rationale behind it. This might be called Google’s version of P4 medicine. The four Ps are predictive, personalized, preventive, and participatory. The shorthand for these four Ps is “personalized” or “precision” medicine. Clearly there is no shortage of Ps — including a P for “pitching” that health care transformation via technology is a sure thing.

In a couple of recent posts I have discussed some of the hype around this vision and also the fact that assuming things like gene scores will lead to widespread participatory and preventive behavior change is a stretch. But what do we know about monitoring? Specifically what do we know about wearables, apps and mobile devices?

Evidence casts doubt on wearable device accuracy

There are at least five recent papers showing that the hope surrounding wearables, monitoring and related apps might in fact be mostly hype. A couple of weeks ago a paper in JAMA Internal Medicine reported that estimates of energy expenditure generated by a number of popular wearables were literally all over the place and just not that accurate. As the authors concluded:

Our study was limited by the small sample size and including only nonobese, healthy participants. Although further studies are required, the findings presented herein suggest that most wearable devices do not produce a valid measure of total energy expenditure.

It is hard to believe that things will get much better when people of all shapes and sizes with various diseases are studied.

Earlier in 2016 another report in JAMA Internal Medicine showed that values provided by an instant blood pressure smartphone app were consistently off the mark. The key finding was summarized by the authors:

The BP measurements from an mHealth app with more than 148 000 units sold were highly inaccurate. The low sensitivity for hypertensive measurements means that approximately four-fifths (77.5%) of individuals with hypertensive BP levels will be falsely reassured that their BP is in the nonhypertensive range.

iStock_000070486739_SmallIn addition to these two studies a well done trial of app-based weight loss in young adults was negative. A study of intensive monitoring after discharge in patients hospitalized with congestive heart failure did not show improved outcomes at six months. The Scripps “Wired for Health” study led by tech-in-medicine advocate Eric Topol was also negative and showed no “clinical or economic benefit from digital health monitoring.”

Human feelings trump monitor readings 

Skepticism is also growing in the mainstream media, with leading exercise science journalist Alex Hutchinson recently writing in the New York Times that:

Last September, in The British Journal of Sports Medicine, Australian researchers published a review of studies that compared subjective and objective measures of “athlete well-being” during training. The objective measures included state-of-the-art monitoring of heart rate, blood, hormones and more; the subjective measure boiled down to asking the athletes how they felt. The results were striking: The researchers found that as the athletes worked out, their own perception registered changes in training stress with “superior sensitivity and consistency” to the high tech measures.

Sounds a bit like Obi-Wan Kenobi encouraging Luke Skywalker to turn off the computer in his X-wing and trust his feelings instead.

The other big issue with high-tech monitoring is that, as with a lot of health-promoting habits, people’s interest flags over time and they stop using the devices. The writer and humorist David Sedaris chronicled his “quitbit” experience in the New Yorker and it is a great read if you are looking for insight and a laugh.

Text messages can be effective

Once you move behind the hype there are a couple of potentially hopeful notes about wearables, apps and mobile technology out there. The first is pretty simple. Text message reminders can help people remember to take their meds and they can also help with smoking cessation. There is a free service at smokefree.gov for those interested. There is also potential that the monitors will get better and perhaps that the feedback they provide can be tailored to specific touch points for a given individual.

In summary, don’t expect wearables, apps and mobile devices to radically transform human health and health care any time soon. However, niche applications like simple text reminders about meds and things like smoking cessation show potential to be effective.

Dr. Joyner has done preclinical technical consulting for GSK, Amgen, Boston Scientific, Edwards, and Nonin on issues related to physiological monitoring, cardiovascular disease and diabetes. He is on the board of Xcede, a startup focused on tissue sealants. As a clinical anesthesiologist he prescribes no drugs or products related to his consulting.

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