Clinical trial NCT03225521: A Micro-randomized Trial of HeartSteps, an mHealth Intervention for Increasing Physical Activity
Official title: HeartSteps: a Just-in-Time Adaptive Intervention for Increasing Physical Activity Amongst Sedentary Adults.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Physical Activity
Keywords: Physical Activity
Mobile Health
Self Monitoring
Wearable Sensors
Tailored Health Communication
Implementation Intentions
Mobile Apps
Anti-Sedentary Behavior
Opportunistic Physical Activity
Health Belief Model
Lead sponsor: Kaiser Permanente
Sponsor class: OTHER
Collaborators: name: National Heart, Lung, and Blood Institute (NHLBI)
First posted: 2017-07-21
Enrollment: 44
Sex: ALL
Minimum age (years): 18
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
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)
Primary purpose: TREATMENT

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.

Eligibility criteria: 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)

Primary outcomes:
measure: 30 minute step count
timeFrame: 30 minutes
measure: Daily step count
timeFrame: 24 hour day
Secondary outcomes:
measure: Thumbs up/down
timeFrame: 30-minute window while message is available
Other outcomes:
Locations:
Study officials:
References:
citation: Boruvka A, Almirall D, Witkiewitz K, Murphy SA. Assessing Time-Varying Causal Effect Moderation in Mobile Health. J Am Stat Assoc. 2018;113(523):1112-1121. doi: 10.1080/01621459.2017.1305274. Epub 2017 Mar 29.
citation: Klasnja P, Hekler EB, Shiffman S, Boruvka A, Almirall D, Tewari A, Murphy SA. Microrandomized trials: An experimental design for developing just-in-time adaptive interventions. Health Psychol. 2015 Dec;34S(0):1220-8. doi: 10.1037/hea0000305.
citation: Liao P, Klasnja P, Tewari A, Murphy SA. Sample size calculations for micro-randomized trials in mHealth. Stat Med. 2016 May 30;35(12):1944-71. doi: 10.1002/sim.6847. Epub 2015 Dec 28.
citation: Klasnja P, Smith S, Seewald NJ, Lee A, Hall K, Luers B, Hekler EB, Murphy SA. Efficacy of Contextually Tailored Suggestions for Physical Activity: A Micro-randomized Optimization Trial of HeartSteps. Ann Behav Med. 2019 May 3;53(6):573-582. doi: 10.1093/abm/kay067.