Differential signaling effects of blood glucose on delay discounting in individuals with and without type 1 diabetes.

Based on the signaling hypothesis of blood glucose (BG), a rise in BG levels signals a positive energy budget for healthy individuals but cellular starvation for individuals with type 1 diabetes. We examined this novel prediction and its intervention implications in the context of delay discounting, the degree to which delayed rewards are discounted, and the regulatory effects of insulin ingestion. We recruited 44 adults with type 1 diabetes (mean age 30.8 years, diabetes duration 15.4 years) and recorded their BG levels. The delay discounting rate was measured using the intertemporal choice task, where participants were required to choose between sets of smaller-and-sooner (SS) and larger-and-later (LL) rewards. In addition, 82 age-matched healthy participants were recruited to provide a baseline comparison on delay discounting. Random forest analysis showed that among many diagnostic factors, delay discounting was most dominating in differentiating the individuals with type 1 diabetes from the control participants. A hierarchical linear mixed model revealed that participants with type 1 diabetes had a stronger preference for SS rewards (p < .001) after controlling for covariates. Participants who had insulin delivered before the last meal exhibited a stronger preference for LL rewards compared to after-meal delivery. In contrast, subjective measures (e.g., self-reported hunger) failed to predict the participants' actual BG levels and delay discounting rates. In sum, individuals with type 1 diabetes tend to discount future rewards excessively compared to the control participants. Pre-meal insulin ingestion was associated with a higher LL preference for future rewards.

Insulin Pumps and Remote Software Updates: A New Way Forward.

This article discusses the future direction of insulin pump technology and its relationship to the software update process. A user needs analysis revealed that respondents wanted an insulin pump software update process to function much in the same way as smartphone updates. Users of insulin pumps have the same expectations as with other ubiquitous technology such as smartphones, tablets, and laptops. The development of a software update system within a regulated environment that meets the needs of insulin pump users by allowing optional software updates that provide access to pump improvements, feature additions, or access to algorithms that provide therapy-changing technologies is a new way forward for the management of a complicated disease that affects more than 450,000 people using insulin pumps in the United States.

Usability and training differences between two personal insulin pumps.

The purpose of this study was to determine if there were usability and training differences between the Medtronic MiniMed Paradigm Revel Insulin Pump and the Tandem Diabetes Care t:slim Insulin Pump during use by representative users, performing representative tasks, in a simulated use environment. This study utilized a between-subjects experimental design with a total of 72 participants from 5 sites across the United States. Study participants were randomized to either the Revel pump group or the t:slim Pump group. Participants were 18 years of age or older and managed their diabetes using multiple daily insulin injections. Dependent variables included training time, training satisfaction, time on task, task failures, System Usability Scale (SUS) ratings, perceived task difficulty, and a pump survey that measured different aspects of the pumps and training sessions. There was a statistically significant difference in training times and error rates between the t:slim and Revel groups. The training time difference represented a 27% reduction in time to train on the t:slim versus the Revel pump. There was a 65% reduction in participants' use error rates between the t:slim and the Revel group. The t:slim Pump had statistically significant training and usability advantages over the Revel pump. The reduction in training time may have been a result of an optimized information architecture, an intuitive navigational layout, and an easy-to-read screen. The reduction in use errors with the t:slim may have been a result of dynamic error handling and active confirmation screens, which may have prevented programming errors.

Human factors research applied: the development of a personal touch screen insulin pump and users' perceptions of actual use.

BACKGROUND: A brief history of the field of human factors research is covered, along with how this discipline is leveraged within medical device companies, to eliminate design flaws in products, in order to make them safe and effective for human use. The way in which human factors research was used to develop the t:slim(®) insulin delivery system (Tandem Diabetes Care(®) Inc., San Diego, CA) is also discussed. Following the development of the t:slim pump, a product evaluation study was conducted to assess users' perceptions of the t:slim pump under actual use conditions versus their current pump system. SUBJECTS AND METHODS: A 30-day, within-subjects study with a total of 74 participants was conducted at four different investigator sites across the United States. Study participants used the t:slim insulin pump in their normal environment for 30 days. Participants were given the Insulin Delivery System Rating Questionnaire during their first visit to assess their current insulin pump and then at the end of the study to measure their perceptions of the t:slim pump. A paired-samples t test was completed to analyze the data. RESULTS: The results indicated that 16 of the questionnaire variables showed statistically significant differences in scores. CONCLUSIONS: It was found that the utilization of a systematic human factors process resulted in an insulin pump that was proved to be safe and effective for human use and was cleared by the Food and Drug Administration for use in the United States. In addition, the results of the product evaluation study showed that, after use of the t:slim pump for 30 days, participants' perceptions of several variables improved.

The role of human factors in the design and development of an insulin pump.

This article discusses human factors (HF) processes and how they are applied during the development of a medical device to minimize the risk that the user interface design could lead to patient errors, adverse events, and product recalls. This process is best defined as "prevention through design." The HF design process is exemplified by three distinct phases: (1) preliminary analysis, (2) formative design evaluation and modification, and (3) design validation. Additional benefits of employing HF principles during medical device development are briefly reviewed, including reduced patient risk by eliminating design flaws, increased patient adherence through the reduction in the complexity of therapeutic regimes, and reduced likelihood for product recalls.