Fitness tracker use is exploding in the US, especially among rich young women

A recent Pew survey shows 21% of US adults regularly wear a smartwatch or fitness tracker. Over half of them think it acceptable for the device makers to share user data with medical researchers.

According to the survey results shared by the Pew Research Center, an American think-tank, smartwatch and fitness tracker adoption may have crossed the chasm from earlier adopters to early majority. 21% of the surveyed panellists already are regularly using smartwatch or specialised tracker to monitor their fitness.

Such a trajectory is in line with the recent market feedback that the total wearables market volume has nearly doubled from a year ago (though what counts as wearables may be contested), and both wristbands and smartwatches have grown by nearly 50%.

When it comes to difference in adoption rates between social groups, the penetration went up to nearly a third (31%) among those with a household income of over $75,000. In comparison, among those with a household income of less than $30,000, only 12% regularly wear such a device. In addition to variance by income groups, women, Hispanic adults, and respondents with a college degree and above are also more likely to wear such devices than men, non-college graduates, and other major ethnic groups.

Another question on the survey asks the respondents if they think makers of a fitness tracking app can share “their users’ data with medical researchers seeking to better understand the link between exercise and heart disease”. The response is divided. 41% of all the respondents said yes, as opposed to 35% saying no, while 22% unsure. However, the percentage of those believing such sharing acceptable went up to 53% among the respondents that are already regularly using such devices, compared to 38% among the non-adopters.

Due to the lack of a GDPR equivalent in the US, it is not much of a surprise that there is neither a consensus among users nor a standard industry practice related to user data sharing. “Recently, some concerns have been raised over who can and should have access to this health data. Military analysts have also expressed concern about how third parties can use the data to find out where there is an American military presence,” Pew said in its press release.

Meanwhile, how useful the data tracked by the devices can be for medical research purposes may also be debatable. For example, even the best of the devices, the Apple Watch, does not qualify as a medical device, despite its being “FDA certified”.

The survey was conducted by Pew from 3 to 17 June 2019. 4,272 qualified panellists responded to the survey.

The FDA certified Apple Watch is still not a medical device

The new Apple Watch has been cleared by the FDA to sell as a low-grade health tracking device but is not producing medical grade data.

At the event where the new iPhones were launched, Apple also launched the 4th iteration Apple Watch. Though it was not the focus of the event, Apple deservedly prided itself for being the first smart watch to pass FDA test. One feature highlighted at the presentation is, by combining the readings from the gyroscope and the accelerometer the Watch can tell when a user has tripped or fallen. If the user stays static after the fall for more than a minute, the cellular equipped Watch can automatically call for help from emergency service or reach out to the family or friend. This can turn out very helpful for the aging population.

Another function of the Apple Watch being marketed is its capability to detect and alert the user irregular heartbeats which can be a symptom of a heart condition called atrial fibrillation, or AFib. This can also be a meaningful feature for a large user group: according to estimates by the US Centers for Disease Control, between 2.7 and 6.1 million people in the US have AFib, many of whom may not be even aware of it.

Apple has conducted an “Apple Heart Study” with Stanford University, the findings of which became the basis on which it gained the FDA clearance. However the total sample size was small (few than 600) and the match rate with professional medical devices was not extremely high. But the data was good enough to convince FDA that the solution worked and it was safe. Apple Watch was given a Class II risk device category, meaning it will not be life threatening even if it does not work. In contrast, if a pacemaker stops working the patient will die, therefore it is classified Class III.

In its approval file to Apple, the FDA demanded Apple to explicitly spell out the possibility of inaccurate reading as well as warn users that the is not a replacement for medical care, although the worst that can happen when the Watch reading is wrong is to cause scare for a healthy user.

Therefore, the new Apple Watch can do the job of a low to mid-range electrocardiogram reader, but it is not a medical device. In a typical professional situation, a patient will have 12 reading leads attached to different parts of the body, including the chest and the limbs, to provide accurate reading. What Apple Watch can give is equivalent to one of them, on the wrist.

No professional physicians will make judgement based on the reading on the Apple Watch. Any sensible users had better not either.