(P153) ASSOCIATION OF NOVEL ACTIGRAPHY ENDPOINTS AND 6-MINUTE WALK DISTANCE IN PATIENTS WITH HEART FAILURE: A PILOT STUDY FROM THE COURTOIS CARDIOVASCULAR SIGNATURE PROGRAM.

Background: Wearable devices provide an opportunity to assess individuals’ real-world mobility and functional capacity via actigraphy measurement for use in clinical trials or epidemiologic studies. However, there have been limited assessments of the association of novel actigraphy endpoints and established prognostic markers of functional capacity such as 6-minute walk distance (6MWD) in patients with heart failure (HF), as defined by self-report or captured from available medical records.
The aim of this pilot study was to investigate the association of smartwatch-captured novel actigraphy endpoints and the 6MWD in patients with HF and in healthy individuals. The actigraphy endpoints included: 1) Duration of longest walk; 2) Steps during longest walk; 3) Steps per minute during longest walk, and 4) Overall steps per minute while watch was worn.

METHODS AND RESULTS: In this study, we used data from participants with well compensated HF (n=36) and age-sex-matched healthy controls (C) with no self-reported history of cardiovascular disease (n=36). Participants were enrolled through the Courtois Cardiovascular Signature Program and completed a 6MWD and subsequently wore the Withings ScanWatch for 5 days. Data was extracted from the watches and preprocessed to adjust for non-wear. Linear regression analysis was used to determine the relationship between novel actigraphy endpoints and 6MWD Moderation analysis was used to investigate the impact of HF status as an effect modifier.
In total (50% HF), the median age was 64.1 (interquartile range [IQR] 56.3, 68.3), 15.3% were female, and the median 6MWD for patients with HF was 476 m (IQR 447 m, 509 m). In the HF group but not controls, manual 6MWD was associated with duration of longest walk (HF: β=0.35, SE=0.18, p=0.049; C: β=-0.06, SE=0.15, p=0.709 (Fig.1)), steps taken during longest walk (HF: β=0.37, SE=0.18, p=0.046; C: β=-0.05, SE=0.14, p=0.747), and steps per minute while watch was worn (HF: β=0.51, SE=0.15, p=0.001; C: β=0.13, SE=0.14, p=0.337 (Fig.2)). Steps per minute during longest walk was not associated with 6WMD in either group (β=0.21, SE=0.20, p=0.298 vs. β=0.05, SE=0.15, p=0.759). HF status did not significantly moderate the association between any actigraphy measure and 6MWD.

Conclusion: This study showed mild-to-moderate associations between actigraphy endpoints (Withings ScanWatch) and manual 6MWD in patients with HF but not in matched controls. Steps per minute during watch-wear demonstrated the strongest associations with 6MWD in the HF group. Further studies in larger and less compensated HF populations are needed to determine the association of novel actigraphy endpoints and traditional markers of HF functional capacity.