A Micro-randomized Trial of HeartSteps, an mHealth Intervention for Increasing Physical Activity (HS)
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|ClinicalTrials.gov Identifier: NCT03225521|
Recruitment Status : Completed
First Posted : July 21, 2017
Last Update Posted : October 25, 2018
|Condition or disease||Intervention/treatment||Phase|
|Physical Activity||Behavioral: HeartSteps: A just-in-time adaptive intervention for increasing physical activity amongst sedentary adults.||Not Applicable|
Physical activity is a key behavioral strategy for prevention of non-communicable diseases such as diabetes and heart disease. Mobile health (mHealth) interventions have shown promise for supporting physical activity adoption and maintenance in ways that are highly acceptable to users, scalable, and cost-efficient. This study examines two intervention strategies—contextually tailored activity suggestions and daily planning of the activity for the next day—that a mobile health intervention can use to encourage physical activity in sedentary adults.
Study participants use HeartSteps, an mHealth physical intervention developed by the research team, in their daily lives for six weeks. Over the course of the study both of the HeartSteps intervention components—contextually-tailored activity suggestions and activity planning—are micro-randomized for each participant on each of the day of the study, in order the effects on physical activity of each component separately and how those effects change over time.
The primary hypothesis for suggestions is that providing a contextually tailored activity suggestion increases participant step count over the subsequent 30 minutes following message delivery.
The first secondary hypothesis for suggestions is that the proximal effect of the contextually tailored activity suggestions on the subsequent 30-minute step count will decrease with duration in the study.
The primary hypothesis for planning is that receiving evening planning will increase step count on the following day.
The primary analyses will use the methods developed in Boruvka et al. (2017). The primary longitudinal outcome for activity suggestions will be the log of the step count in the 30 minutes subsequent to decision points. The log of the step count in the 30 minutes prior to randomization will be included as a control variable. The primary longitudinal outcome for planning will be the square root of the step count on the day following the randomization of planning treatment.
All missing but "available" minute-by-minute step counts from the wrist band will be imputed as 0. See "Allocation" section for the definition of availability. Sensitivity analyses using step counts from the mobile phone (secondary data source) will be conducted.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||44 participants|
|Intervention Model:||Single Group Assignment|
|Intervention Model Description:||Each participant-time point is randomized between intervention or no intervention (delivery of a contextually tailored activity suggestion or no suggestion; planning or no planning)|
|Masking:||None (Open Label)|
|Official Title:||HeartSteps: a Just-in-Time Adaptive Intervention for Increasing Physical Activity Amongst Sedentary Adults.|
|Actual Study Start Date :||July 18, 2015|
|Actual Primary Completion Date :||February 1, 2016|
|Actual Study Completion Date :||February 1, 2016|
Experimental: HeartSteps intervention
For activity suggestions, at each available decision time, each participant is randomly assigned to either receive an activity suggestion or not. The randomization probability is 0.6 for receiving a message and 0.4 for not receiving a message.
For activity planning, at each decision point, the participant is randomized to either receive evening planning or not at that decision time. The randomization probability for receiving planning is 0.5, and 0.5 for not receiving planning.
Behavioral: HeartSteps: A just-in-time adaptive intervention for increasing physical activity amongst sedentary adults.
HeartSteps is an Android-based mHealth intervention that contains two main intervention components: contextually-tailored suggestions for activity and planning of the next day's activity. Activity suggestions provide individuals with actionable suggestions for how they can be active in their current context. Delivered suggestions are tailored based on time of day, user's location, day of the week (weekend/weekday), and weather. HeartSteps can deliver a user activity suggestions up to five times a day. Evening planning asks users to create or choose a plan of how they will be active on the following day. Planning can be delivered once a day, in the evening.
- 30 minute step count [ Time Frame: 30 minutes ]30-minute window after each available decision point
- Daily step count [ Time Frame: 24 hour day ]Daily step count on the day following treatment
- Thumbs up/down [ Time Frame: 30-minute window while message is available ]User ratings of message usefulness (thumbs up/thumbs down rating)