JMIR Publications

ABSTRACT

Background:

Cardiovascular disease and type 2 diabetes mellitus are posing a huge burden on healthcare systems worldwide. Mobile apps can deliver behavior change interventions for chronic disease prevention on a large scale, but current evidence for their effectiveness is limited.

Objective:

This manuscript reports on the development and user testing of a mobile app that aims at increasing risk awareness and engaging users in behavior change. It would form part of an intervention for primary prevention of cardiovascular disease and type 2 diabetes mellitus.

Methods:

The theoretical framework of the app design was based on the Behaviour Change Wheel, combined with the COM-B system (capability, opportunity, and motivation for behavior change), and the behavior change techniques from the Behaviour Change Technique Taxonomy v1. Additionally, evidence from scientific literature guided the development process. The prototype was tested for user-friendliness via an iterative approach. We conducted semi-structured interviews with individuals of the target populations which included the System Usability Scale. We transcribed and analyzed the interviews using descriptive statistics for the System Usability Scale and thematic analysis to identify app features that improved utility and usability.

Results:

The target population was Australians aged 45 years and older. The app included 4 core modules (risk score, goal setting, health measures, and education). In these modules, users learned about their risk for cardiovascular disease and type 2 diabetes mellitus, set goals for smoking, alcohol consumption, diet, and physical activity and tracked these. In total, we included 12 behavior change techniques. We conducted two rounds of usability testing, each with 5 participants. The average age was 58 years (SD: 8). Six participants owned iOS phones and 4 owned Android phones. In the first round, we identified a technical issue that kept 3 from completing the registration. Among the 7 who were able to complete the registration, 5 rated the app above average based on the System Usability Scale. During the interviews, we identified some issues relating to functionality, content, and language and clarity. We used the participants’ feedback to improve on these aspects.

Conclusions:

We developed the app using behavior change theory and scientific evidence. The user testing allowed us to identify and remove technical errors and integrate additional functions into the app that the participants had requested. Next, we will evaluate the feasibility of the revised app version developed through this design process and usability testing.