Fitness trackers do more than just count your steps. A new study published by the Scripps Research Translational Institute today in Nature shows that activity trackers and personal health sensing devices such as Fitbits and smartwatches can improve COVID-19 detection. A team of Scripps researchers set out to determine if smartwatch and activity tracker data could accurately detect COVID-19 among symptomatic people, when combined with self-reported symptoms. The group developed a smartphone app that amassed data from more than 30,000 people in the U.S. between March 25 and June 7, 2020. Among the test sample, 3,811 reported COVID-19 symptoms. Of the symptomatic individuals, 54 said they tested positive for the virus and 279 reported they tested negative. Among the test group, 78.4% used Fitbit devices, 31.2% used connected data from the Apple HealthKit, and 8.1% used data from Google Fit. (Totals are greater than 100% because some participants used more than one device). The study analyzed three data types from the wearables: daily resting heart rate, sleep duration in minutes, and step count.
The Scripps researchers analyzed the collected data to determine if using the wearable device data with self-reported symptoms improved COVID-19 detection more than self-reported symptoms alone. The full study report breaks down the data types more specifically, but overall, the accuracy of COVID-19 detection was about equal for either data source by itself. A combined score for resting heart rate, sleep minutes, and steps had a 0.72 probability score while the self-reported symptoms scored a probability of 0.71. When the team combined the participant-reported symptoms with the sensor data, however, the probability of accurately discriminating between positive and negative COVID-19 test results rose to a probability score of 0.80. The concept of the quantified self has been intriguing for its potential to determine useful health information beyond just the number of steps taken in a day. At this point in the world’s struggle to cope with the pandemic, tools that assist in the accurate diagnosis of COIVD-19 are particularly important. The Scripps app isn’t a perfect or complete solution, but it adds significant data that points to the potential role of wearables in much more than just determining activity.