I often take pot shots at “expensive pedometers that aren’t very accurate,” but the fact is that the traditional “fitness tracker” is morphing into a useful device for health and medical applications. My smartwatch initially overcounted my steps by a factor of 3. (A recent firmware upgrade brought that down to a more reasonable level.) Fitness bands are getting more sensors and new algorithms that are able to deduce useful information from apparently unrelated measures. These devices have improved so much that researchers are interested in using them to monitor patients after discharge from the hospital, or subjects in clinical trials. The big problem with these applications is getting subjects to adhere to the measurement process; using a convenient wearable that could constantly collect the required data might improve the results.
That was the concept behind a new study undertaken by Cedars-Sinai and UCLA. The researchers wanted to see if test subjects would use a consumer-grade fitness band more reliably that other telehealth monitoring devices. They also wanted to demonstrate the validity of the data recorded by the system. They settled on the Fitbit Charge 2 because it also has optical sensors to measure heart rate using photoplethysmography (PPG). The device also is able to identify periods of sleep or when the subject has taken off the device, by pairing the motion data with the heart rate information.
The results showed an outstanding level of adherence. Among 200 subjects with ischemic heart disease (IHD) over a 90-day period, some used the device as much as 90% of the time. Average adherence was 87.7% at the start and declined to 72.0% at the end of the three months. This amounts to less than a 1% decline in adherence across the time period. The data collection also made it easier to send reminders to subjects, which may have helped keep adherence levels high. The subjects also completed health questionnaires, and the results from the activity trackers correlated closely with the activity and health reports provided by the subjects.
This means that wearables like these could be effective tools at monitoring the progress of heart disease patients when they are away from the hospital or other clinical setting. It also means that they may not have to complete the questionnaires that are typically part of a monitoring program. This approach for remote monitor could also lead to early warnings about deteriorating patient health, and could well be useful for other chronic health conditions as well.
