Formative usability evaluation of a web-based insulin self-titration system: preliminary results.

We developed a web-based system supporting patients in insulin self-titration and their caregivers in monitoring patients' self-management activities. Since usability flaws could cause user attrition and compromise patient safety, we evaluated the system's usability prior to its implementation in practice. Two pairs of researchers conducted cognitive walkthrough sessions and identified 81 unique usability problems, including four with a potential impact on patient safety. Usability evaluations could reveal many usability problems and allow solving the problems while avoiding user attrition and potential adverse patient events.