Faculty of Physical Education and Sport, Charles University, Prague, Czech Republic.
2nd Department of Medicine - Department of Cardiovascular Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
PLoS One. 2019 Sep 13;14(9):e0222569. doi: 10.1371/journal.pone.0222569. eCollection 2019.
Although 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.
Six 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).
In 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.
Even 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.
尽管已经有许多活动追踪器在健康人群中得到了验证，但在正常行走速度较慢的慢性心力衰竭患者中，验证工作仍存在不足，这使得研究人员和临床医生在进行体力活动干预时难以使用活动监测器。
在一项为期 3 天的现场研究中，对 6 种消费级别的活动监测器在慢性心力衰竭患者和健康个体的自由生活条件下进行了验证。此外，还在实验室跑步机步行速度为 2.4、3.0、3.6 和 4.2km·h-1的条件下对相同的设备进行了评估。采用 concordance correlation coefficient（CCC）来评估活动监测器与标准之间的一致性，mean absolute percentage error（MAPE）用于评估每个设备与标准之间的差异（MAPE<10%被认为是有效性的阈值）。
在健康个体的现场研究中，除了一个活动监测器外，所有监测器与标准设备的相关性均较强（CCC≥0.95），MAPE<10%。在心力衰竭患者中，只有两个活动监测器（Garmin vívofit 3 和 Withings Go）的相关性被归类为至少中度（CCC≥0.90），没有任何设备的 MAPE<10%。在实验室基于速度为 4.2 和 3.6km·h-1 的研究中，所有活动监测器与标准之间的相关性均较强到几乎完美（CCC≥0.95），MAPE 在 1%-3%的范围内。然而，在速度较慢的 3.0 和 2.4km·h-1 时，所有设备的准确性都大大恶化：它们与标准的相关性降至 90%以下，MAPE 分别增加到 4-8%和 10-45%。
尽管没有一个测试的活动监测器符合任意有效性阈值，但它们中的大多数都表现得相当好，足以成为临床医生可以用来简单地激励慢性心力衰竭患者多走路的有用工具。
