Michigan Medicine in Ann Arbor released early results from a three-year study that examined using Apple Watches and iPhones in clinical research and reported discrepancies with some of the data that was recorded, according to a report published in The Lancet Digital Health.
There were 6,723 Michigan Medicine patients who participated in the study. The study required patients to have an iPhone 6 or newer and wear an Apple Watch for 90 days. Patients wore their watches for 90 percent of the study days, averaging more than 15 hours per day. The 90-day study is part of a three-year observational study funded by Apple and the Ann Arbor-based University of Michigan.
Four insights:
1. The smartwatches collected more than 200 million heart rate measurements and 1.1 million blood pressure readings with the Omron blood pressure cuff, according to an Oct. 26 news release. Michigan Medicine compared the data collected from the Apple Watch to information from other sources, such as EHR data and information from the blood pressure cuffs.
2. Jessica Golbus, MD, co-investigator on the study and physician with the cardiovascular medicine division at Michigan Medicine, said in the release that the study unveiled a significant discrepancy in activity levels as measured by the Apple Watch and iPhone. Apple's iPhone also had a much lower step count than what was shown on Apple Watches.
"I think what this means is that not all mobile device signals are created equal and that, in the future, interpretation of these signals will require knowledge of the device from which these signals were collected," Dr. Golbus said.
3. The study also found that the iPhone has a shorter battery life than other devices, which can influence results, according to the report.
4. Overall, the researchers concluded that smartwatch data could inform clinical trial design, clinical interpretation of wearable data, health interventions and risk predictions, according to the report.