A text-messaging and pedometer program to promote physical activity in people at high risk of type 2 diabetes: A development and feasibility study for the PROPELS Trial

Background: Mobile technologies for health (mHealth) represent a promising strategy for reducing type 2 diabetes (T2DM) risk. The PROPELS trial investigates whether structured group-based education alone or supplemented with a follow-on support programme combining self-monitoring with pedometers and tailored text-messaging is effective in promoting and maintaining physical activity (PA) among people at high risk of T2DM. Objective: This paper describes the iterative development of the PROPELS follow-on support programme and presents evidence on its acceptability and feasibility. Methods: We used a modified mHealth development framework with four phases: 1) conceptualisation of the follow-on support programme using theory and evidence; 2) formative research including focus groups (participants: n=15, aged 39-79 years); 3) pre-testing focus groups using a think aloud protocol (participants: n= 20, aged 52-78 years); and 4) piloting (participants: n= 11). Analysis was informed by the constant comparative approach, with findings from each phase informing subsequent phases. Results: The first three phases informed the structure, nature and content of the follow-on support programme, including the frequency of text-messages; the need for tailored content and two-way interaction; the importance of motivational messages based on encouragement and reinforcement of affective benefits (e.g., enjoyment), with minimal messages about weight and T2DM risk; and the need for appropriate language. The refined programme is personalised and tailored to the individual’s perceived confidence, previous activity levels and PA goals. The pilot phase indicated that the programme appeared to fit well with everyday routines and was easy to use, also by older adults. Conclusions: We developed a feasible and innovative text-messaging and pedometer programme based on evidence and behaviour change theory and grounded in the experiences, views and needs of people at high diabetes risk. A large scale trial is testing the effectiveness of this four-year programme over and above structured group education alone. Trial registration: ISRCTN83465245