Is Activity Tracker–Measured Ambulation an Accurate and Reliable Determinant of Postoperative Quality of Recovery? A Prospective Cohort Validation Study

BACKGROUND: Quality of recovery (QOR) instruments measure patients' ability to return to baseline health status after surgery. Whether, and the extent to which, postoperative ambulation contributes to QOR is unclear, in part due to the lack of valid tools to measure ambulation in clinical settings. This cohort study of the cesarean delivery surgical model examines the accuracy and reliability of activity trackers in quantifying early postoperative ambulation and investigates the correlation between ambulation and QOR. METHODS: A prospective cohort of 200 parturients undergoing cesarean delivery between July 2015 and June 2017 was fitted with wrist-worn activity trackers immediately postpartum. The trackers were collected 24 hours later, along with QOR assessments (QoR-15 scale). The relationship between QOR and various covariates, including ambulation, was explored using multivariable linear regression and Spearman correlation (ρ). Forty-eight parturients fitted with 2 trackers also completed a walk exercise accompanied by a step-counting assessor, to evaluate accuracy, inter-, and intradevice reliability using interclass correlation (ICC). RESULTS: Compared to step counting, activity trackers had high accuracy (ICC = 0.93) and excellent inter- and intradevice reliability (ICC = 0.98 and 0.96, respectively). Correlation analysis suggested that early ambulation is moderately correlated with postcesarean QoR-15 scores, with a ρ (95% confidence interval) equivalent to 0.56 (0.328–0.728). Regression analysis suggested that ambulation is a determinant of postcesarean QoR-15 scores, with an effect estimate (95% confidence interval) equivalent to 0.002 (0.001–0.003). Ambulation was also associated with all QoR-15 domains, except psychological support. The patient's acceptable symptom state (subjective threshold for good ambulation) in the first 24 hours was 287 steps. CONCLUSIONS: This study demonstrated the accuracy and reliability of activity trackers in measuring ambulation in clinical settings and suggested that postoperative ambulation is a determinant of postoperative QOR. A hypothetical implication of our findings is that interventions that improve ambulation may also help to enhance QOR, but further research is needed to establish a causal relationship. Accepted for publication October 5, 2018. Funding: This work was supported by departmental funding. J.G.L., D.N.W., and F.W.A. were supported by the Merit Award Program, Department of Anesthesia, University of Toronto. F.W.A. also receives research time support from the Department of Anesthesiology and Pain Medicine, and the Ottawa Hospital Research Institute, University of Ottawa. D.N.W. is also supported by a New Investigator Award from the Canadian Institutes of Health Research. The authors declare no conflicts of interest. Reprints will not be available from the authors. Address correspondence to Faraj W. Abdallah, MD, Department of Anesthesiology and Pain Medicine, University of Ottawa, The Ottawa Hospital General Campus, 501 Smyth Rd, Ottawa, ON K1H 8L6, Canada. Address e-mail to FAbdallah@toh.ca. © 2018 International Anesthesia Research Society

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