Higher postoperative step counts measured with wearable devices were associated with shorter hospital stays and lower odds of complications and readmissions among adults undergoing inpatient surgery, according to an observational analysis of data from the All of Us Research Program.
In scenario modeling, patients whose activity increased from 1,000 fewer steps per day to 1,000 more steps per day relative to baseline had a mean length of stay of 1.92 days compared with 2.60 days—an absolute difference of 0.68 days. In adjusted models, each additional 1,000 steps per day was associated with a 6% shorter length of stay.
The study included 1,965 adult patients with electronic health record–linked wearable data following an index inpatient operation. Most patients underwent intermediate-risk procedures, and the mean age was 50 years. Cardiac and flap procedures were excluded because of potential heart rate variability artifacts and immobility requirements.
Postoperative step counts declined overall by a mean of 1,428 steps per day relative to baseline, indicating that higher activity largely reflected smaller postoperative declines rather than increases above baseline.
Higher postoperative step counts were associated with lower odds of 30- and 90-day complications and readmissions. Associations with specific complication types were most evident at 30 days, including respiratory and thromboembolic events and higher-grade complications. At 90 days, most subtype associations were not observed, although reduced odds of grade 4 complications persisted.
The association between activity and length of stay was strongest among patients undergoing high-risk procedures, more modest among low-risk procedures, and smallest among intermediate-risk procedures.
Postoperative changes in heart rate variability and self-reported wellness were not independently associated with length of stay, complications, or readmissions. Heart rate variability was derived from wrist-based photoplethysmography and calculated using the SDANN metric, a long-term variability measure that may be less sensitive to acute autonomic changes than other commonly used indices.
Self-reported wellness scores were generally not associated with outcomes, although they were linked to 90-day complications in one adjusted model.
Overall, 17% of patients experienced a complication within 30 days and 6% were readmitted within 30 days.
The findings should be interpreted cautiously. The study was observational and cannot establish causality. Wearable data were collected without a standardized protocol, and patients who were readmitted had substantially fewer days of wearable data than those who were not readmitted (approximately 6 vs 21 days), raising concern for bias in the readmission analyses.
“Postoperative activity was a consistent and actionable predictor of recovery, associated with shorter [length of stay], fewer complications, and lower 90-day readmissions,” wrote Abdulaziz Elemosho, MD, of The Ohio State University Wexner Medical Center and James Comprehensive Cancer Center, and colleagues.
The researchers reported no conflicts of interest, no funding, and no financial support.
