Validity of six consumer-level activity monitors for measuring steps in patients with chronic heart failure

Abstract

IntroductionAlthough numerous activity trackers have been validated in healthy populations, validation is lacking in chronic heart failure patients who normally walk at a slower pace, making it difficult for researchers and clinicians to implement activity monitors during physical activity interventions.MethodsSix consumer-level activity monitors were validated in a 3-day field study in patients with chronic heart failure and healthy individuals under free living conditions. Furthermore, the same devices were evaluated in a lab-based study during treadmill walking at speeds of 2.4, 3.0, 3.6, and 4.2 km·h-1. Concordance correlation coefficients (CCC) were used to evaluate the agreement between the activity monitors and the criterion, and mean absolute percentage errors (MAPE) were calculated to assess differences between each device and the criterion (MAPE <10% was considered as a threshold for validity).ResultsIn the field study of healthy individuals, all but one of the activity monitors showed a substantial correlation (CCC ≥0.95) with the criterion device and MAPE <10%. In patients with heart failure, the correlation of only two activity monitors (Garmin vívofit 3 and Withings Go) was classified as at least moderate (CCC ≥0.90) and none of the devices had MAPE <10%. In the lab-based study at speeds 4.2 and 3.6 km·h-1, all activity monitors showed substantial to almost perfect correlations (CCC ≥0.95) with the criterion and MAPE in the range 1%-3%. However, at slower speeds of 3.0 and 2.4 km·h-1, the accuracy of all devices substantially deteriorated: their correlation with the criterion decreased below 90% and their MAPE increased to 4–8% and 10–45%, respectively.ConclusionsEven though none of the tested activity monitors fall within arbitrary thresholds for validity, most of them perform reasonably well enough to be useful tools that clinicians can use to simply motivate chronic heart failure patients to walk more.

Advances in accelerometry for cardiovascular patients: a systematic review with practical recommendations

“…The two other studies assessed step accuracy of accelerometers by visual observation on the treadmill and during free walking at various speeds. They both found that at speeds slower than 3.0–3.6 km/h, the accuracy of the devices substantially deteriorates 29,58 …”

“…Furthermore, the step‐counting algorithms provided by various manufacturers are all proprietary and use different thresholds of acceleration to detect a step, which limits the comparability among studies using different devices 73 . Despite numerous validation studies showing that most commercially available accelerometers are more or less equal in general populations with normal gait, 74,75 other studies have reported that step‐counting accuracy deteriorates in patients with chronic conditions, particularly during slower gait speeds 58,76 . As such, steps can still remain a useful self‐monitoring metric for patients but should be avoided by researchers striving for high accuracy and reproducibility of their findings.…”

“… (1)Limit the use of steps only to the studies that focus on walking, for example, when the aim of the intervention is to increase daily number of steps, or when participants are instructed to self‐monitor their steps 57 . In addition, researchers and clinicians must be cognizant of the inaccuracy of most devices at slow gait speeds 58 (2)Use time spent in PA intensity levels with caution, especially in patients with reduced cardiorespiratory fitness.…”

“…57 In addition, researchers and clinicians must be cognizant of the inaccuracy of most devices at slow gait speeds. 58 (2) Use time spent in PA intensity levels with caution, especially in patients with reduced cardiorespiratory fitness.…”

Wrist-Worn Activity Trackers in Laboratory and Free-Living Settings for Patients With Chronic Pain: Criterion Validity Study

“…A strict comparison of our study findings with other research within this population was not possible due to the lack of such studies. On the other hand, studies have been conducted aiming to evaluate criterion validity in wrist-worn activity trackers among an elderly population [ 56 ] as well as among populations suffering from chronic cardiac conditions [ 57 , 58 ]. These reports also suggest an overestimation of energy expenditure.…”