Providers Can Glean Useable Health Metrics from Wearable Tracker Data

November 22, 2022 - Data from wearable activity trackers can be used to determine various health metrics, including users' cardiovascular health status, new research shows.

Conducted by Johns Hopkins Medicine, the study was published in npj Digital Medicine earlier this month.

According to researchers, though the use of wearable sensors, like activity trackers, has grown significantly in recent years, they are primarily used to measure daily step counts. The researchers' objective in conducting this study was to show that clinically relevant metrics beyond daily step count can be gathered from wearable activity trackers.

"There is a large resource of untapped information contained within the data from these devices, enabling a much more granular fingerprint of an individual's activities of daily life," they wrote in the study.

The researchers examined activity tracker-obtained data for 22 individuals with pulmonary arterial hypertension (PAH) provided by Cleveland Clinic. The individuals wore the tracker, a Fitbit, between two clinic visits. Cleveland Clinic staff collected 26 health measurements for each participant at both visits, including health-related quality of life assessments, heart rate measurements, and results from the six-minute walk distance (6MWD) test, a commonly used aerobic capacity and endurance test.

They then used participants' minute-to-minute step rate and heart rate data to determine several metrics linked to physical and cardiovascular health. These metrics included the distribution of heart rate, the intensity and frequency of walks during each week, and the results from an analog version of the 6MWD test.

"Together these parameters provide [a] weekly signature of an individual's status that could be used for identifying subgroups within patient populations or assessing changes over time," the researchers wrote.

For instance, the researchers compared the activity-tracker metrics with the 26 metrics collected during the clinic visits and found that fitness assessments based on activity-tracker data correlated with NT-proBNP, a blood biomarker for heart failure, measured in the clinic. Overall, they found significant differences in 18 of these metrics across the 22 study participants.

"Finding so many statistically significant differences in a relatively small cohort suggests to us that activity-tracker data may make it possible to identify surrogate markers of disease severity that can be monitored remotely," said Peter Searson, PhD, senior author of the study and the Joseph R. and Lynn C. Reynolds professor at the Johns Hopkins University Whiting School of Engineering, in the press release. "These data could potentially contribute to the identification of patients who would benefit from more frequent clinic visits or specific medications."

Wearables, including fitness trackers, are growing increasingly popular. According to a survey of 2,005 US consumers in the first quarter of 2022, 41 percent own a smartwatch or fitness tracker, up 2 percentage points from 2021. A vast majority (90 percent) of those who own these devices use them to track fitness and monitor health.

Most respondents appear satisfied with their wearable devices, with 70 percent saying the devices helped improve their fitness and health. About 55 percent of wearable device owners also said they share their data with their healthcare providers.

But there are several challenges to using wearables data in clinical care, especially in cardiac care, cardiologists told mHealthIntelligence last month. These include the potential for collecting inaccurate data, difficulties in selecting the most appropriate device, and data privacy concerns.

Despite these challenges, the cardiologists interviewed agreed that as wearable device applicability and accuracy expand, they will continue to play a significant role in cardiology.