Using consumer-grade physical activity trackers to measure frailty progression in critical care survivors: An exploratory observational study (Preprint)
BACKGROUND Critical illness has been suggested as a sentinel event for frailty development for at-risk older adults. Frail critical illness survivors suffer increased adverse health outcomes but monitoring the recovery post-Intensive Care Unit (ICU) is challenging. Clinicians and funders of healthcare system envision an increased role of wearable devices in monitoring clinically relevant measures as the sensor technology is advancing rapidly. Use of wearable devices also generated great interest among older patients and they are the fastest growing group of consumer-grade wearable device users. Recent research studies indicate that consumer-grade wearable devices offer a possibility of measuring frailty. OBJECTIVE To examine the data collected from wearable devices for the progression of frailty among the critical illness survivors. METHODS An observational study was conducted with 12 critical illness survivors from Kingston General Hospital in Canada. Frailty was measured by Clinical Frailty Scale (CFS) at ICU admission (AD), hospital discharge (DC), and 4-week follow-up (FU). Wearable device was worn between DC and FU. The wearable device collected data on steps, physical activity, sleep and heart rate (HR). Patient assessments were reviewed including the severity of illness, cognition level, delirium, activities of daily living, and comorbidity. RESULTS The CFS increased significantly following critical illness compared pre-ICU frailty level (P=.02, d=-0.53). Frail survivors over the 4-week follow-up period had significantly lower daily step counts than non-frail survivors (P=.02, d=1.81). There was no difference in sleep and HR measures. Daily step count was strongly correlated with the CFS at FU (r=-0.72, P=.04). Average HR was strongly correlated with the CFS at DC (r=-0.72, P=.046). HR standard deviation was strongly correlated (r=0.78, P<0.05) with the CFS change from AD to FU. No assocation was found between the CFS and sleep measures. The pattern of increasing step count over the FU period was correlated with the worsening of frailty (r=.62, P=.03). CONCLUSIONS This study demonstrated association between frailty and data generated from a consumer-grade wearable device. Daily step count and HR showed strong association with the frailty progression of the critical illness survivors over time. Understanding this assocation could unlock a new avenue for clinicians to monitor and identify a vulnerable subset of the population that might benefit from an early intervention. CLINICALTRIAL