Wearables Anticipate Postoperative Complications: A Prospective Cohort Study

Consumer wearable devices enable continuous passive physiologic monitoring in free-living conditions, yet their capacity to detect early postoperative deterioration following hospital discharge remains poorly characterized. Here we report a prospective observational cohort study evaluating multimodal wearable-derived physiologic signals across the perioperative period in adults undergoing elective oncologic surgery at Duke University Health System. Participants were monitored using an Oura Ring Gen 2 and Garmin Vivosmart 4 from at least two weeks preoperatively through up to 90 days postoperatively, alongside daily electronic patient-reported pain surveys. Devices captured 3,705 participant-days and 82,833 hours of physiologic data across 46 surgical patients. Oura adherence averaged 21.0 hours/day and was significantly higher than Garmin throughout the study period (17.6 hours/day). Garmin wear time declined significantly following surgery, while Oura adherence remained comparatively stable. Postoperative complications occurred in 17 participants (37%), including 10 major complications (Clavien-Dindo grade IIIb or higher) with a median onset of 13 days after surgery. Patients with major complications demonstrated significantly greater peak deviations from baseline in the first 10 postoperative days across resting heart rate, sleep temperature deviation, and readiness metrics. In the days before clinically documented major complications, wearable and patient-reported signals diverged from those of participants without major complications, with reduced activity appearing as early as four days before the event, followed by higher reported pain and later elevations in resting heart rate and sleep temperature deviation. These findings support the feasibility of prolonged perioperative wearable monitoring and suggest that physiologic deterioration preceding major surgical complications may be detectable days before clinical documentation, motivating further development and validation of wearable-based postoperative surveillance strategies.