Abstract 15451: Using Fitbit Measured Activity Levels as an Indicator of New York Heart Association (nyha) Functional Class

Introduction: Commercially available wearable devices for physical activity (PA) monitoring may provide objective data to facilitate assessment of NYHA class in patients with heart failure (HF). However, there is limited research exploring their ability to differentiate patients between NYHA classes. Objective: This study aims to assess the relationship between NYHA class and PA using a Fitbit wrist-based activity tracker (Charge 3) in patients with HF. Methods: We conducted a secondary analysis of baseline NYHA and PA data (daily step count and minutes of moderate-to-vigorous PA [MVPA]) collected by the iCardia4HF trial, which examined the feasibility and preliminary efficacy of a mHealth intervention for HF self-care. NYHA class was determined by a trained research assistant at the baseline visit, using standardized criteria. Daily steps and MVPA minutes were measured using Fitbit data from the first 7 days after the baseline visit. To be included in the analysis, patients had to have ≥4 days with ≥600 minutes of Fitbit wear-time/day. Results: We analyzed data from 78 participants (mean age=55.2 years [SD 10.6]; female=43.6%; Black/African American= 79.5%; mean BMI=35.6 kg/m2 [SD 8.7]; HFrEF=65.4%). The Kruskal-Wallis test demonstrated significant differences in the distribution of daily steps (p=.021) and MVPA (p=.023) across NYHA classes. Pairwise comparisons showed that patients in NYHA Class III had significantly lower daily steps and MVPA minutes than patients in Class I. There were also important differences in daily steps and MVPA between patients in NYHA Class III and II, and Class II and I, but these did not reach statistical significance. Conclusions: There was a general decrease in steps and MVPA duration with increasing NYHA class. Wrist-worn activity trackers represent a promising method for estimating NYHA class and assessing HF severity and progression through continuous PA monitoring, but larger studies are needed for validation.