Usability of a Wrist-Worn Smartwatch in a Direct-to-Participant Randomized Pragmatic Clinical Trial

Abstract

Background: The availability of a wide range of innovative wearable sensor technologies today allows for the ability to capture and collect potentially important health-related data in ways not previously possible. These sensors can be adopted in digitalized clinical trials, i.e., clinical trials conducted outside the clinic to capture data about study participants in their day-to-day life. However, having participants activate, charge, and wear the digital sensors for long hours may prove to be a significant obstacle to the success of these trials.

Objective: This study explores a broad question of wrist-wearable sensor effectiveness in terms of data collection as well as data that are analyzable per individual. The individuals who had already consented to be part of an asymptomatic atrial fibrillation screening trial were directly sent a wrist-wearable activity and heart rate tracker device to be activated and used in a home-based setting.

Methods: A total of 230 participants with a median age of 71 years were asked to wear the wristband as frequently as possible, night and day, for at least a 4-month monitoring period, especially to track heart rhythm during sleep.

Results: Of the individuals who received the device, 43% never transmitted any data. Those who used the device wore it a median of ∼15 weeks (IQR 2-24) and for 5.3 days (IQR 3.2-6.5) per week. For rhythm detection purposes, only 5.6% of all recorded data from individuals were analyzable (with beat-to-beat intervals reported).

Conclusions: This study provides some important learnings. It showed that in an older population, despite initial enthusiasm to receive a consumer-quality wrist-based fitness device, a large proportion of individuals never activated the device. However, it also found that for a majority of participants it was possible to successfully collect wearable sensor data without clinical oversight inside a home environment, and that once used, ongoing wear time was high. This suggests that a critical barrier to overcome when incorporating a wearable device into clinical research is making its initiation of use as easy as possible for the participant.

Keywords: Electrocardiography; Photoplethysmography; Wearability; Wearable sensors; Wearables.

Fig. 1

Presentation of the Amiigo device to the study participants as shown on the mSToPS website. mSToPS, mHealth Screening to Prevent Strokes.

Fig. 2

Distribution of the number of days of usage of the device for the participants who collected photoplethysmography data at least once. On the x axis we have different intervals of the number of days of usage, e.g., between 0 and 25 days, while on the y axis we represent the number of participants using the device for that specific number of days.

Fig. 3

Average number of minutes of recorded signal per day for the participants wearing the device at least once. This value strictly depends on the time in which the device was worn by the participant (during the day, at night, or both). The distribution of this value is shown in the figure, where we divided the x axis into short intervals of 5 min, while on the y axis we represent the number of participants with average minutes per day included in that specific interval.

Fig. 4

Distribution of the number of minutes recorded per participant. On the x axis we have intervals of number of minutes, represented in a logarithmic scale for clarity, while on the y axis we have the number of participants corresponding to each interval.

Fig. 5

Total amount of collected and analyzable data per participant.