Harnessing Digital Health to Objectively Assess Functional Performance in Veterans with Chronic Obstructive Pulmonary Disease

Abstract

Introduction: An early detection of impaired functional performance is critical to enhance symptom management for patients with chronic obstructive pulmonary disease (COPD). However, conventional functional measures based on walking assessments are often impractical for small clinics where the available space to administrate gait-based test is limited. This study examined the feasibility and effectiveness of an upper-extremity frailty meter (FM) in identifying digital measures of functional performance and assessing frailty in COPD patients.

Methods: Forty-eight patients with COPD (age = 68.8 ± 8.5 years, body mass index [BMI] = 28.7 ± 5.8 kg/m2) and 49 controls (age = 70.0 ± 3.0 years, BMI = 28.7 ± 6.1 kg/m2) were recruited. All participants performed a 20-s repetitive elbow flexion-extension test using a wrist-worn FM sensor. Functional performance was quantified by FM metrics, including speed (slowness), range of motion (rigidity), power (weakness), flexion and extension time (slowness), as well as speed and power reduction (exhaustion). Conventional functional measures, including timed-up-and-go test, gait and balance tests, and 5 repetition sit-to-stand test, were also performed.

Results: Compared to controls, COPD patients exhibited deteriorated performances in all conventional functional assessments (d = 0.64-1.26, p < 0.010) and all FM metrics (d = 0.45-1.54, p < 0.050). FM metrics had significant agreements with conventional assessment tools (|r| = 0.35-0.55, p ≤ 0.001). FM metrics efficiently identified COPD patients with pre-frailty and frailty (d = 0.82-2.12, p < 0.050).

Conclusion: This study proposes the feasibility of using a 20-s repetitive elbow flexion-extension test and wrist-worn sensor-derived frailty metrics as an alternative and practical solution to evaluate functional performance in COPD patients. Its simplicity and low risk for test administration may also facilitate its application for remote patient monitoring. Furthermore, in settings where the administration of walking test is impractical, for example, when ventilator support is needed or space is limited, FM may be used as an alternative solution. Future studies are encouraged to use the FM to quantitatively monitor the progressive decline in functional performance and quantify outcomes of rehabilitation interventions.

Keywords: Chronic obstructive pulmonary disease; Frailty phenotypes; Functional performance; Upper-extremity frailty meter; Wearable technology.

Figure 1:

Experimental design. In a seated position, a wearable sensor was attached to a participant’s dominant wrist. Participants were instructed to perform a 20-second elbow flexion-extension test with their dominant arm as fast as they could.

Figure 2:

Relationship between FM metrics and conventional functional measures among the COPD and control groups. (A) Linear relationship was significant between FM Speed (slowness) and normalized gait speed among all participants. (B) Linear relationship was significant between FM Range of Motion (rigidity) and eyes-closed balance center of mass sway among all participants. (C) Linear relationship was significant between FM Flexion Time (slowness & weakness) and 5STS completion time among all participants. (D) Linear relationship was significant between FM Extension Time (slowness & weakness) and TUG completion time among all participants.

Figure 3:

Representation of group comparison on (A) FM Speed (slowness), (B) FM Power (weakness), (C) FM Flexion Time (slowness & weakness), and (D) FM Extension Time (slowness & weakness). Each bar represents mean, and error bars represent a standard error of the corresponding mean.