[brady8]

I'm a physician. Agree with your comment... in a statistical sense this relates to screening test characteristics. As the sensitivity of a test increases, the specificity decreases.

A good example is screening for atrial fibrillation, an abnormal heart rhythm that is not uncommon especially as you age. All our guidelines right now on treatment and stroke prevention (a potential consequence of AF) is based on the population who is currently most often diagnosed - symptomatic patients with palpitations, or lightheadedness, or chest pain, which provokes them to see a physician.

If everyone is now wearing an Apple watch and suddenly we have 2x or 10x the number of people diagnosed with AF, our current evidence about the benefits of treatment suddenly do not apply, because these newly found patients would never have been included in the original studies.

So what do we do with these (presumably lower risk) patients? No one yet knows.

[rapjr9]

Yes, exactly why new evidence is needed, new RCT's.