A Micro-randomized Trial of HeartSteps, an mHealth Intervention for Increasing Physical Activity

Not Applicable

Completed

• Conditions: Physical Activity

• Registration Number: NCT03225521
• Lead Sponsor: Kaiser Permanente

Brief Summary

The aim of this research is to evaluate the efficacy of contextually tailored activity suggestions and activity planning for increasing physical activity among sedentary adults.

Detailed Description

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 Timeline

• Study Start: 2015-07-18
• Primary Completion: 2016-02-01
• Study Completion: 2016-02-01
• Study First Submitted: 2017-07-19
• Study First Submitted QC: 2017-07-19
• Study First Posted: 2017-07-21
• Status Verified: 2018-10
• Last Update Submitted: 2018-10-23
• Last Update Posted: 2018-10-25

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 44

Inclusion Criteria

• English speakers,
• between 18 and 60 years of age,
• could walk for exercise without discomfort, and
• either had a full-time daytime job or a regular schedule outside the home (e.g., students)
• have a personal phone running Android 5.0 or higher or willing to use a study-provided phone as their primary phone for the duration of the study.

Exclusion Criteria

• Need medical supervision to exercise
• Currently using an activity tracker (e.g., FitBit)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Primary Outcome Measures

Name	Time	Method
30 minute step count	30 minutes	30-minute window after each available decision point
Daily step count	24 hour day	Daily step count on the day following treatment

Secondary Outcome Measures

Name	Time	Method
Thumbs up/down	30-minute window while message is available	User ratings of message usefulness (thumbs up/thumbs down rating)