Wearable Monitoring Tech May Not Always Be Good for Your Health

As our health gadgets get smarter and more connected, there's a real risk of overdiagnosis in healthy users.

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Sep 1 2016, 4:30pm

The Nike Fuel Band is just one example of a litany of devices that attempt to quantify your wellbeing. Image: Intel Free Press/Flickr

It's mid-morning, and you're at work. Your smartphone buzzes, a notification— "HealthAlert triggered. Await call."

A moment later, your phone rings. The caller introduces himself as a medical technician from the live health monitoring service you subscribe to. Some unusual readings have been detected on your EKG. It's probably no cause for concern, but perhaps you could answer some follow-up questions.

Yes, you do feel a little nauseous, and yes, your skin does maybe feel a little clammy, now that he mentions it. No, you have no chest pain or shortness of breath. You forget, in the moment, yesterday's late night and "one or two" drinks with old college friends. The technician, his voice level and professional, advises—just as a precaution—that you should be checked out at the hospital. An ambulance has been called.

This may seem far-fetched, but the market in wearable health monitoring devices, particularly targeting the "worried well"—people without specific health problems, who are concerned with managing their health and wellness—is exploding, with predictions that the global market in medical wearable devices will more than double, from $3.2 billion in 2015 to almost $8 billion in 2020. The QardioCore, launched at this year's CES by Qardio, "the only company that cares as much about design as about medical accuracy," awaits FDA approval. Strapped around your chest, it provides live EKG, respiratory rate, and even an assessment of your stress levels via an iOS app. Companies like PhysIQ, meanwhile, are chomping at the bit to commercialize remote health monitoring services, identifying a key market to "empower health-conscious consumers." With subscription models a favored strategy of technology companies, it's only a matter of time.

But what about you? By now, you've been wheeled into an emergency room wearing nasal oxygen prongs. Several hours, an EKG, echocardiogram, numerous blood samples and a precautionary dose of anticoagulant medication later, you're discharged from hospital. There's nothing wrong with your heart—it was a false alarm. What a relief!

A good news story, then; the occasional false alarm and resulting nuisance are surely worth the chance to detect a life-threatening problem?

At what cost, though?

A sick day you didn't need to take. And large bill for you, your medical insurer, or your country's social health service—for an uninsured patient in the US, this hospital visit could easily set you back around $10,000 and potentially considerably more. You suffered unnecessary worry, uncomfortable diagnostic tests, and were given medications that could cause serious side effects, all because of an uninterpretable wobble detected by a health gadget.

False positives in routine screening—such as Pap smears, mammograms, and PSA tests—are a well-recognized problem. Evidence suggests that each 10,000 screening mammograms performed on women between the ages of 50 and 59 will produce 932 "false alarms" leading to further investigations, tests, and potentially to unnecessary biopsies and surgeries being performed on healthy patients. There is no perfect diagnostic test—every test will return some negative results when they should have been positive, and vice versa.

Imagine a good test, which produces a false positive result one time in 100. Used in sick patients whose doctors suspect a disease, it will produce one additional, incorrect positive result along with, say, 50 true positive results. If the test says you're sick, there's about a 2 percent chance it's wrong. This same test, screening 100 healthy people where just 3 percent are genuinely affected would still return that single false positive—this time alongside just three genuine results. Now, if the test says you're sick, there's a 25 percent chance it's wrong. The less common the disease, the stronger this effect becomes. The more different tests you run—the more parameters you monitor, and the more often—the more likely you are to be caught out.

There are plenty of reasons for caution as we rush into this new world of personalized healthcare—not least privacy and data security concerns—but the risk of overdiagnosis and unnecessary medical interventions should, perhaps, also cause us to pause before we strap the next generation of monitors to our chests and head out to work.

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