Fitbit Data to Assess Functional Capacity in Patients Before Elective Surgery: Pilot Prospective Observational Study

Area of Science:

• Cardiology
• Geriatrics
• Sports Medicine
• Medical Devices

Background:

• Preoperative assessment is vital for surgical risk stratification, traditionally focusing on functional capacity.
• Wearable devices offer a less invasive, cost-effective, and potentially more accurate approach to functional capacity assessment.
• Smartwatches, trackers, and rings are increasingly accessible for continuous health monitoring.

Purpose of the Study:

• To evaluate the utility of commercial smartwatch data (Fitbit Inspire 2) for preoperative functional capacity assessment.
• To correlate smartwatch-derived metrics with the established 6-Minute Walk Test (6MWT) as the gold standard.

Main Methods:

• Patients underwent the 6-Minute Walk Test (6MWT) during a hospital visit.
• Participants wore a Fitbit Inspire 2 for approximately 7 days post-visit and pre-surgery.
• Resting heart rate and daily step data were extracted; feature engineering created Heart Rate over Steps (HROS) and Non-Exercise Testing Cardiorespiratory Fitness (NEF) metrics.
• All smartwatch-derived metrics were correlated with 6MWT distance.

Main Results:

• The Non-Exercise Testing Cardiorespiratory Fitness index showed the strongest correlation with 6MWT (r=0.68, P<.001).
• Average resting heart rate also correlated significantly (r=-0.39, P=.03).
• Fitbit step count demonstrated a fair correlation with 6MWT (r=0.59, P<.001).

Conclusions:

• Smartwatch data shows strong correlation with the 6MWT, indicating promise for wearable technology in preoperative functional capacity evaluation.
• Future research should address limitations in metric availability, device variability, data accuracy, and accessibility.
• This study serves as a foundational step towards integrating consumer wearables into clinical preoperative assessments.