Apple Watch can detect arrhythmia with 97% accuracy, study says
We need to see the full, published study and its methods (particularly around recruitment and exclusion criteria) before we can judge it properly. Until then, the presented statistics about accuracy, sensitivity, and specificity potentially bear no relation to real world usage, if the cohort and data quality were tightly controlled, as you&#x27;d expect for an initial study involving the makers of the algorithm. A few other thoughts:<p>1. Even at 98% sensitivity and 90% specificity [0], which I don&#x27;t think would hold up with real world usage in casual, healthy users, if AFib has a prevalence of roughly 2-3% [1] then by a quick back of the envelope calculation a positive test result is still 5× more likely to be a false positive than a true positive. With those odds, I don&#x27;t think many cardiologists are going to answer the phone. You&#x27;d still need an EKG to diagnose AFib.<p>2. There is huge variance among people&#x27;s real world use of wearable sensors, and also among the quality of the sensors. (Imagine people that wear the watch looser, sweat more, have different skin, move it around a lot, etc.) You&#x27;d likely need to do an open, third-party validation study of the accuracy of the sensors in the Apple Watch before you can expect doctors to use the data. My understanding is that the Apple Watch sensors are actually pretty good compared to other wearable sensors, but I don&#x27;t know of any rigorous study of that compares them to an EKG.<p>3. Obviously, this is only for AFib. AFib is a sweet corner case in terms of extrapolating from heart rate to arrhythmia, because it&#x27;s a rapid &amp; irregular rhythm that probably contains some subpatterns in beats that are hard for humans to appreciate. As others—including Cardiogram themselves [2]—have pointed out previously, many serious arrhythmias are not possible to detect with only an optical heart rate sensor.<p>[0]: <a href="https:&#x2F;&#x2F;blog.cardiogr.am&#x2F;applying-artificial-intelligence-in-medicine-our-early-results-78bfe7605d32" rel="nofollow">https:&#x2F;&#x2F;blog.cardiogr.am&#x2F;applying-artificial-intelligence-in...</a><p>[1]: <a href="https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pubmed&#x2F;24966695" rel="nofollow">https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pubmed&#x2F;24966695</a><p>[2]: <a href="https:&#x2F;&#x2F;blog.cardiogr.am&#x2F;what-do-normal-and-abnormal-heart-rhythms-look-like-on-apple-watch-7b33b4a8ecfa#fabf" rel="nofollow">https:&#x2F;&#x2F;blog.cardiogr.am&#x2F;what-do-normal-and-abnormal-heart-r...</a>