Accelerometer-measured physical activity pattern in older patients with frailty and heart failure

Abstract Background Physical activity (PA) assessed by accelerometers represents a novel method to understand the PA profile of older patients with heart failure (HF). We hypothesized that PA level and pattern vary in HF patients across the spectrum of frailty status. Aim To report the duration, intensity and volume of PA in older patients with HF according to frailty status. Methods We recruited 150 HF patients≥65 years from a hospital-based HF clinic between March and October 2023. Frailty was assessed using the Short Physical Performance Battery (SPPB); patients with SPPB 10-12, 7-9, 4-6 and ≤3 was classified as robust, mildly, moderately and severely frail respectively. To evaluate PA profile, all patients wore a wrist accelerometer on their non-dominant hand for 7 days (24 hours/ day). PA parameters including average acceleration over 24 hours (proxy of volume of activity); time spent in inactive, light, moderate and vigorous intensity activities; intensity gradient (more negative gradient equates to poorer intensity profile) and time of most active continuous bouts of PA, were compared amongst frailty groups. Results 146 participants with good quality accelerometer data were included in the analysis; median age 80 (range 65-94 years), 65% male. Thirty-eight percent had heart failure with reduced ejection fraction (HFrEF); 21% had NYHA class III/IV symptoms; median NT-proBNP was 2040 ng/L (IQR = 1110 - 4930). Frail patients were more likely to be older with more comorbidities; they also had more severe HF symptoms and higher NT-proBNP. Frail patients had lower volume of PA compared to robust patients, evidenced by lower average acceleration (milligravity-mg) over 24 hours [20.4 (robust); 16.0 (mildly frail); 13.5 (moderately frail); 13.2 (severely frail), p<0.001]. PA intensity profile was poorer in frail patients compared to robust patients [median intensity gradient: -2.72 (robust); -2.92 (mildly frail); -3.00 (moderately frail); -3.07 (severely frail), p<0.001]. (Table 1) Frail patients spent more time inactive compared to robust patients [median time spent inactive (minutes): 654 (robust); 689 (mildly frail); 780 (moderately frail); 720 (severely frail), p<0.001]. The median time (minutes) spent in light [225 (robust); 190 (mildly frail); 164 (moderately frail); 159 (severely frail)] and moderate to vigorous activity [62 (robust), 23 (mildly frail), 15 (moderately frail) and 13 (severely frail), p<0.001] were significantly shorter in frail compared to robust patients. (Figure 1) The most active continuous bout of PA of patients across the frailty spectrum appeared to between 10 AM to 2 PM. Conclusion The duration, volume and intensity of PA was generally low in older patients with HF. Worse frailty status was associated with longer duration of physical inactivity, shorter duration of light, moderate or vigorous activity, poorer PA intensity profile and lower volume of PA.