Understanding the dilemma of wearable medical devices with Apple Watch 4

1. Apple’s Electrocardiogram Application

What comes to mind when you think of wearable devices? Actually, any device that can be worn on the body falls under wearable devices. From glasses like Google Glass aimed at augmented reality to smart socks that can record pressure exerted on your feet during jogging, there are countless types of wearable devices to be found.

In this wearable market, the most common product is arguably the smartwatch. The functions of smartwatches vary widely from measuring sleep time and patterns while you sleep to applications with fall detection capabilities. Features like monitoring your heart rate and daily activity are basic nowadays.

The most notable product in the smartwatch market is undoubtedly the Apple Watch, a gadget known widely even among those who aren’t particularly interested in smartwatches. On September 12, Apple made headlines when the atrial fibrillation detection application and electrocardiogram (ECG) measurement application based on heart rate, added to the Apple Watch 4, received FDA medical device approval in the US. (This feature has not yet been introduced in Korea.)

Figure 1. Yes, it’s the same electrocardiogram often seen in medical dramas.

Apple is effectively claiming that wearable devices and applications can function as medical devices. The process of measuring an electrocardiogram using the Apple Watch is very simple. Install the electrocardiogram application on the Apple Watch, launch the app, rest your arms comfortably, and place the opposite hand’s fingers on the crown of the Apple Watch. Maintain this posture for 30 seconds to get a single-lead electrocardiogram recorded for 30 seconds.

After the measurement, based on the electrocardiogram, the Apple Watch informs you if your heart is beating normally, whether it’s too fast or too slow, or if there’s atrial fibrillation. Although it doesn’t provide as comprehensive data as the 12-lead electrocardiograms used in hospitals, the single-lead ECG from the Apple Watch is still expected to deliver useful information. The results from the Apple Watch can be stored as PDF files, making it easy for users to share with others.

Figure 2. By placing the hand on the crown like this, you can measure a single-lead electrocardiogram.

However, following Apple’s announcement, concerns have been raised that the ECG measurement and atrial fibrillation detection on the Apple Watch can cause problems in various ways. This article aims to discuss the criticisms Apple Watch faces as a leading product in the wearable medical device market, as well as the issues wearable medical devices, in general, need to overcome.

2. FDA Approval Process for the ECG Application

In fact, Apple’s process for obtaining FDA approval has been controversial in many ways. The Apple Watch applications that received approval this time were approved through the De Novo pathway. The term “De Novo” literally means new, indicating that there were no similar pre-existing approved devices. However, it’s questionable whether the Apple Watch truly represents a new product given that products like AliveCor, which allow ECG measurement using the Apple Watch, had already been approved. The FDA claims that Apple’s ECG app is differentiated from other devices as it is a purely software-based mobile medical device.

(Apple Watch received “clearance” instead of “approval” like AliveCor, meaning it was permitted to include the ECG tracking and atrial fibrillation detection features but didn’t receive complete approval as a medical device.)

Figure 3. Part of the FDA approval document for the Apple Watch ECG app.

One notable point is that it generally takes more than 150 days to get De Novo approval from the FDA. However, it took only about a month for Apple’s applications to receive approval. While Apple had been in contact with the FDA for several years regarding related matters, some still argue that the approval was granted too quickly. Moreover, the approval date coinciding with Apple’s launch event for the Apple Watch allowed Apple to keep the news from leaking before their announcement. Was this all just a coincidence? [4]

3. Criticisms of the Apple Watch as a Medical Device

While the controversies surrounding the approval process are certainly interesting, the main point of concern is whether Apple’s applications are practically useful enough to be called medical devices. There are great expectations for the actual medical utility of these products, beyond merely measuring sleep time and heart rate.

Cases exist where severe bradycardia or tachycardia were detected through smart devices and treated, and some people discovered they had atrial fibrillation for the first time through the Apple Watch. Considering these cases, the Apple Watch clearly provides value by offering various people the opportunity to screen their ECG. Despite this utility, Apple’s ECG application faces various criticisms. Let’s briefly examine these specific criticisms.

The first criticism is regarding the medical device approval itself. In the case of smartwatches like Fitbit, they primarily collect user activity or sleep data. In most cases, they simply display this data in an appealing way rather than offering direct recommendations based on it.

Figure 4. How Fitbit displays data, offering only light suggestions such as “get more sleep” if you’re not getting enough rest.

Many smartwatches stop at displaying data for several reasons, the main one being the unclear liability in case the advice provided is incorrect. When it comes to medical advice apps that can significantly impact the user’s life, the responsibility for the outcome is substantial.

Even medical tests used in hospitals can have errors. If smartwatch sensors or algorithms, no matter how accurate, fail and lead to incorrect predictions, who will bear the responsibility? Let’s consider a few hypothetical scenarios, even if they may be somewhat exaggerated.

3.1. Diagnostic Errors Due to Software

Mr. A recently bought a wristband. This band measures the wearer’s blood pressure and advises them to visit a hospital when the levels are dangerously high. One day, the band warns Mr. A of high blood pressure, advising a hospital visit. Trusting the band, Mr. A visits the hospital only to find out the test results are normal. However, worried about his health, Mr. A insists on additional tests, which also come back normal. This means the app’s diagnosis was wrong.

Another scenario involves Mr. B, who bought the band hoping for its blood pressure check feature. Wearing the band daily, Mr. B eventually felt uncomfortable but ignored it because the band didn’t alert him of any issue. When the discomfort worsened, disrupting daily life, he finally visited a hospital and found out he had multiple complications due to high blood pressure. Immediate medical attention might have prevented these complications if not relying on the band.

Who should compensate Mr. A for his financial and time losses due to the two tests? If the band manufacturer pays, how much should they pay? In Mr. B’s case, who is responsible for the failed diagnosis? The band or Mr. B for overly relying on it?

There’s currently no clear answer to these questions. Liability is a significant issue preventing the market release of autonomous vehicles, despite their near-completion functionally. MIT’s “Moral Machine” project, which studies public perceptions of ethical decisions by AI, such as self-driving cars, also reflects this issue.

Figure 5. MIT Moral Machine project survey asking participants about value judgments in self-driving car accidents.

The issue of liability is one that not only the Apple Watch but all wearable devices must resolve to transition from interesting accessories to items that provide real-life benefits. Displaying data alone isn’t enough; interpreting the results and conveying them to the user is crucial for the effectiveness of wearable devices.

While I enjoy analyzing my exercise and sleep data collected by Fitbit, many users prefer software that directly interprets the data for them. Thus, Apple’s attempt to bridge data collection and medical interpretation is encouraging. However, if a medical device providing health judgments, such as the Apple Watch, is released without resolving the issue of liability, could it be considered irresponsible?

3.2. Errors from Inexperienced Users

Errors in analysis can also arise from user mistakes. All sensors require specific conditions for accurate analysis. For example, to analyze sleep patterns accurately, one needs to sleep in a comfortable bed, not on a frequently moving massage chair. Users must adhere to proper conditions and methods for measurement, but it’s unrealistic to expect all users to do so accurately.

Figure 6. A doctor’s tweet about a patient who visited due to abnormal ECG signals recorded by their Apple Watch.

In this tweet, a patient reports abnormal ECG signals measured by an Apple Watch. While it’s possible there’s a genuine ECG abnormality, it’s more likely that incorrect measurements were taken since the patient was able to walk to the doctor. The high chances of user error reveal that the Apple Watch’s ECG feature could potentially cause unnecessary worries for users. These incorrect measurements may outnumber genuine heart issues detected, possibly making the Apple Watch ECG screening more trouble than it’s worth.

Figure 7. User errors could potentially lead to major disasters.

3.3. Is It Truly Useful?

Another point of debate is whether the Apple Watch’s ECG/atrial fibrillation detection is practically useful. The ability to measure one’s ECG anytime and record atrial fibrillation seems highly beneficial for user health. Indeed, atrial fibrillation is the most common form of arrhythmia and a major risk factor for strokes.

The Apple Watch allows users to measure their ECG when feeling unwell and show the results to their doctor, which can be convenient for those troubled by arrhythmias. However, what about people without any such symptoms? Is it useful for them to periodically check their ECG for atrial fibrillation? Many argue it isn’t.

The United States Preventive Services Task Force (USPSTF) recently published a paper in the Journal of the American Medical Association (JAMA). According to this paper, ECG screening for people without significant heart disease symptoms doesn’t necessarily benefit health. In fact, incorrect diagnoses leading to unnecessary tests or treatments might harm the user. [8]

Consider the example of the prostate-specific antigen (PSA) test, commonly used. Although PSA is normally produced in the prostate, it’s also a marker for prostate cancer.

Figure 8. Early detection of prostate cancer doesn’t always result in positive outcomes. [9]

The figure shows the results of an experiment comparing groups that underwent PSA testing (right) for early prostate cancer detection and those that did not (left). There was no difference in the number of prostate cancer deaths (dark red) between the two groups. Instead, the test led to unnecessary biopsies (green) or unnecessary treatments for non-progressing cancers (light blue). In other words, the tests caused harm by leading to unnecessary procedures without improving patient outcomes.

(The PSA test is primarily used to monitor cancer recurrence after treatment rather than to diagnose the disease itself since the levels can increase due to other prostate conditions. Nonetheless, the use of PSA for prostate cancer screening remains a controversy. [10])

Comparing the PSA test directly to the Apple Watch ECG application isn’t straightforward. The Apple Watch Series 4 has been out for a short time, and the ECG application is not yet available in many countries, including Korea. In such a situation, we lack sufficient information to determine whether Apple’s ECG monitoring genuinely promotes health or saves lives.

However, readers who have followed along are likely to understand the concerns that the ECG monitoring feature might cause more harm than benefit. Just as incorrect PSA tests led to unnecessary procedures, Apple’s ECG feature could result in unnecessary hospital visits due to errors.

4. Conclusion

The issues raised thus far are challenges that all wearable medical devices face, not just Apple Watch, due to their nature as devices likely to monitor rather than directly treat conditions.

Can Apple disproves predictions that the harms of their ECG/atrial fibrillation detection will outweigh the benefits and establish itself as a pioneering leader in this market? Or will other companies learn from Apple’s example, resolving these dilemmas and creating actually helpful wearable medical devices for users? Apple’s recent move is hence intriguing, and observing how Apple addresses these issues might serve as an indicator of the future direction of the wearable medical devices market.

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References:

[1] https://www.southwales.ac.uk/study/subjects/nursing-health-sciences/short-courses/ecg/

[2] https://support.apple.com/en-us/HT208955

[3] https://www.accessdata.fda.gov/cdrh_docs/pdf18/DEN180044.pdf

[4] http://www.yoonsupchoi.com/2018/09/21/apple-watch4-ecg/

[5] https://www.fitbit.com/kr/app

[6] http://moralmachine.mit.edu/hl/kr

[7] https://twitter.com/Dr_Markman/status/1074374628053827584

[8] Jin, Jill. “Screening for Atrial Fibrillation With Electrocardiography.” Jama, vol. 320, no. 5, July 2018, p. 516., doi:10.1001/jama.2018.10598.

[9] https://www.harding-center.mpg.de/en/fact-boxes/early-detection-of-cancer/prostate-cancer-early-detection

[10] https://www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementFinal/prostate-cancer-screening1