Warning: This health information might be hazardous to your health
By Daniel Oran, Associate Director, Scripps Research Translational Institute | December 19, 2018
The recently launched ECG app for the Apple Watch is truly a marvel of miniaturization. It puts on your wrist capabilities previously found only in bulky electrocardiograph machines. Instead of trekking to a doctor’s office, you can now measure your own heart rhythm wherever you are, whenever you want. And notably, according to Apple, the ECG app accurately detects atrial fibrillation (AFib), in which the heart’s upper chambers — the atria — quiver, instead of squeezing as they usually do to pump blood into the lower chambers, the ventricles.
This certainly sounds like an incredible medical breakthrough. Suddenly, all those who own an Apple Watch and an iPhone can now continuously monitor themselves for AFib. What could be wrong with that? Well, a lot, actually. Because routinely screening for health conditions that don’t have noticeable symptoms is a surprisingly risky activity. It can open a Pandora’s box of harm for the unsuspecting patient.
As an example, consider the prostate-specific antigen (PSA) blood test that’s still widely used as a screening tool for prostate cancer in men over 50. As you can see for yourself in the elegant chart below from the Harding Center for Risk Literacy, screening is not necessarily a benign activity. This analysis suggests that, as a result of prostate cancer screening, as many as one in five men suffers through unnecessary testing or treatment. 
What does a similar chart look like for continuous AFib monitoring using a consumer-grade wearable device like the Apple Watch? We simply don’t know. The long-term data that we need for that analysis have not yet been collected.
We’re entering an era of abundant, ubiquitous health information, collected by sensors and devices that were unavailable or even unimaginable just a few years ago. Today, it’s do-it-yourself heart rhythm monitoring. Soon, it’s likely to be continuous monitoring of blood pressure and blood sugar using non-prescription devices.
More is not always better, though, when it comes to health information. That’s why we need rigorous clinical trials that evaluate the impact of digital health information on patient outcomes.
Meantime, an old-fashioned dumb watch might be better for your health than the latest smartwatch.
For more information, contact press@scripps.edu