Fitbit has started a large-scale, virtual study in the USA on the use of its wearable technology to identify atrial fibrillation (AFib), the most common form of heart rhythm irregularity.
 
The study is part of the company’s broader strategy to make easy-to-use tools that accelerate detection of a range of conditions more accessible. The Fitbit Heart Study aims to enrol hundreds of thousands of people, and its results will support the company’s regulatory submissions globally.
 
AFib affects nearly 33.5 million people globally and patients with AFib have a five times higher risk of stroke. It can also be difficult to detect, as episodes can be sporadic and asymptomatic, and some studies suggest that as many as a quarter of people who have an AFib-related stroke only find out they have AFib after a stroke has occurred.
 
“Until recently, tools for detecting AFib had a number of limitations and were only accessible if you visited a doctor,” said Steven Lubitz, principal investigator of the Fitbit Heart Study, cardiologist at Massachusetts General Hospital and associate professor of medicine at Harvard Medical School. “My hope is that advancing research on innovative and accessible technology, like Fitbit devices, will lead to more tools that help improve health outcomes and reduce the impact of AFib on a large scale.”
 
Fitbit wearables have the potential to accelerate AFib detection because their round-the-clock heart rate tracking is powered by long battery life, which allows users to wear their device for multiple days at a time. This enables long-term heart rhythm assessment, including when users are asleep. The optimal way to identify irregular rhythm through heart rate tracking technology is to screen when the body is at rest, making assessment overnight, while people sleep, ideal for detection.
 
“Since we first brought heart rate tracking to the wrist in 2015, we have continued to innovate and provide users with a deeper understanding of their heart health through features like sleep stages, cardio fitness level and now active zone minutes,” said Eric Friedman, Fitbit co-founder and CTO. “The Fitbit Heart Study advances our heart health efforts. Long-term passive heart rhythm assessment with our wide range of affordable devices powered by 24/7 heart rate tracking technology has the potential to improve earlier identification of AFib, which is a key to reducing the risk of a life-threatening event like stroke. By doing this important research we have the opportunity to develop and provide access to technology that may be able to improve public health and save lives.”
 
To track heart rate, Fitbit’s devices use photoplethysmography (PPG) technology to measure the rate of blood flow directly from a user’s wrist. Theoretically, these measurements can be used to determine a user’s heart rhythm, which Fitbit’s algorithm will analyse for irregularities in the study. Participants who receive a notification about an irregular heart rhythm will be connected with a doctor for a virtual appointment at no cost to get more information and may receive an electrocardiogram (ECG) patch in the mail at no cost to confirm the notification.
 
The study is part of Fitbit’s broader approach to heart health innovation, which includes industry partnerships and the development of other technologies focused on raising awareness and accelerating detection of AFib to reduce the risk of stroke and improve population health. In addition to the technology being examined in the study, the company has made progress in the development of a new ECG feature for spot detection of AFib.
 
Fitbit aims to provide users with long- and short-term AFib assessment options based on their individual needs and is developing PPG and ECG tools that could offer long-term assessment and spot-check AFib detection. The PPG-based heart rhythm tool is designed to identify irregular rhythm episodes with no symptoms that might otherwise go undetected, and the ECG feature is designed to support those who want to screen themselves for possible AFib and record an ECG trace they can review with their doctor.
 
The company has completed a pivotal clinical trial of its ECG feature and plans to seek review by the US Food & Drug Administration (FDA) and global regulatory authorities.
 
Additionally, following FDA clearance for the PPG AFib algorithm, Fitbit will continue to work with the Bristol-Myers Squibb-Pfizer Alliance to develop programmes and educational content that will help identify and support people in the USA at increased risk for stroke to provide a continuous and supported care pathway that extends to AFib diagnosis.
 
The study is open to people in the USA aged 22 years and older with a current Fitbit device that tracks heart rate. Participant data will be kept confidential and will only be shared with study partners in connection with the study.