Perceptions of Usability and Design for Prefilled Insulin Delivery Devices for Patients With Type 2 Diabetes

Abstract

Although many patients with type 2 diabetes are initially managed through lifestyle modification, most eventually require insulin therapy. However, insulin initiation is often delayed because of factors such as patients' resistance to insulin therapy and worries about injections. Such delays affect glycemic control, have a direct effect on patient encounters, and may affect medication adherence. Insulin pen delivery systems may address some of these concerns. This study had two phases. First, semi-structured qualitative interviews were conducted to identify the most important features of insulin delivery devices for prandial use from the perspective of patients (n = 8) and health care professionals (HCPs; n = 10). From phase 1, a 26-item questionnaire was developed. In phase 2, patients (n = 33 insulin naive, n = 78 pen users) and HCPs (n = 151) were asked to indicate the most important features to them in insulin delivery devices. Patients then simulated injection using three different pens (SoloSTAR, KwikPen, and FlexPen) and ranked them based on the same features. The most important features were knowing that the entire dose has been injected, ease of reading the dose correctly, and ease of correcting if the dose is over-dialed. In the simulation study, KwikPen and SoloSTAR scored significantly higher (paired t test, P < 0.05) than FlexPen on “knowing if you have injected the entire dose” (mean score out of 10: KwikPen, 8.9; SoloSTAR, 8.6; and FlexPen, 8.4). No other significant differences among the pens were noted in usability or design, and the mean ranking (from 1 to 3) of the pens was similar (KwikPen, 2.0; FlexPen, 2.1; and SoloSTAR, 1.9). By identifying which insulin delivery pens offer these features, HCPs can choose the most appropriate delivery device for patients, which may lead to earlier insulin initiation, greater patient adherence, and better clinical outcomes.