New Apple Apps: Overdiagnosis, Useful Addition, or Both?

[Lawpy]

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From Medscape

Company Release

FDA Statement: "Consumers are now empowered to take more control of their own health information to make better informed decisions about their medical care and healthy living. These advances enable better health outcomes for patients."

Some takeaways regarding the Apple Watch Series 4:

"The redesigned watch includes a sensor that can take an electrocardiogram (ECG) reading in 30 seconds and classify whether the heart is beating normally or there are signs of atrial fibrillation (AF). The recordings are stored in the health app in a PDF file that can be shared with physicians. With watchOS 5, the watch can also intermittently analyze heart rhythms and alert the user if it detects an irregular rhythm or if their heart rate exceeds or falls below a specified threshold"

"The second app uses an accelerometer and gyroscope to determine and alert users if they have taken a hard fall. If the watch senses immobility for 60 seconds after the alert, it will automatically call emergency services and message the location to emergency contacts."

"American Heart Association president, Ivor J. Benjamin, MD, said patients often report symptoms that are absent during office visits, and thus the ability to access on-demand ECG data is "game changing, especially when evaluating atrial fibrillation." He also suggested that products that offer "deeper health insights," such as Apple's new heart-health features, have "great potential" to improve patients' lifelong health and avoid stroke, heart failure, and other health problems."

"Medscape editor-in-chief, Eric Topol, MD cautioned that the ECG feature could increase the chance of false-positives and may detect cases of low-risk AF that don't need to be treated... He also noted that while the Apple watch captures heart rate, it does not measure oxygen saturation, blood pressure, or even breathing rate."

"Medscape columnist and electrophysiologist John Mandrola, MD, said the app could misdiagnose patients because of inaccurate readings or lead to overtreatment of patients."

"The ECG app is not recommended for users diagnosed with AF or for people under age 22 years... the data are captured only when the user is still and that the feature is not intended to replace traditional methods of diagnosis or treatment."

What are your thoughts?

 

[Tenk]

My thoughts are I am glad I mostly work in a rural ED where nobody wears an Apple iwatch.

 

[nimbus]

I think it’s great. I’m going to get one.

 

[Dro133]

A cardiologist on Twitter had a great mini-"Tweetorial" on this -- you can read it here:



In summary: assuming one million people buy the watch and a prevalence of 1% for a-fib in the general population, given the algorithm's sensitivity of 98% and specificity of 90%, the new feature will correctly diagnose ~1,000 new cases of a-fib at the cost of ~100,000 false positive diagnoses. Read the twitter thread for a more detailed explanation.

 

[Raney Schauer]

This is the first step towards our A.I. robot overlords monitoring and managing us....

[on Dave's return to the ship, after HAL has killed the rest of the crew]

HAL: Look Dave, I can see you're really upset about this. I honestly think you ought to sit down calmly, take a stress pill, and think things over.

 

[Raney Schauer]

Great Job, Raney! Now share your anterior wall M.I. with your friends!

 

[Raney Schauer]

 

[libertyyne]

A cardiologist on Twitter had a great mini-"Tweetorial" on this -- you can read it here:



In summary: assuming one million people buy the watch and a prevalence of 1% for a-fib in the general population, given the algorithm's sensitivity of 98% and specificity of 90%, the new feature will correctly diagnose ~1,000 new cases of a-fib at the cost of ~100,000 false positive diagnoses. Read the twitter thread for a more detailed explanation.

Are those clinically significant cases of a FIB? If so would they not have been caught under normal circumstances ? Seems like a one way ticket to unnecessary testing.

 

[mistafab]

It will change big data when we can get big data collection.

I hope people can opt-in to sharing aggregate/anon data so we can move research forward with all these new toys.

 

[Dro133]

Are those clinically significant cases of a FIB? If so would they not have been caught under normal circumstances ? Seems like a one way ticket to unnecessary testing.

My apologies, I left out one number: it's estimated that 10% of a-fib is clinically silent (Screening for undiagnosed atrial fibrillation in the community. - PubMed - NCBI). Thus in a population of 1 million people with the watches, there would be an estimated 10,000 people with a-fib (1%), and 10% of those would be undiagnosed (1,000 people).