Development and Validation of the Diabetes Pen Experience Measure: A New Patient-Reported Outcome Measure

Abstract

Background: Satisfaction with insulin-delivery devices has been shown to improve treatment adherence, translating into better glycemic control. The Diabetes Pen Experience Measure (DPEM) is a new patient-reported outcome measure to evaluate patients’ experience when using an injection device. Methods: The DPEM was developed using literature review and concept elicitation interviews with clinical experts and patients. This led to a theoretical model and a draft measure of the diabetes pen experience, which was refined following cognitive debriefing. Validation entailed a web-based, noninterventional survey; psychometric analyses conducted according to a statistical analysis plan; and refinement and finalization of the DPEM and theoretical model. Results: In total, 42 patients participated in concept elicitation interviews. Analysis of the qualitative interviews resulted in a preliminary theoretical model. Based on this model, DPEM items were generated; the preliminary version of the DPEM contained 30 items. Following cognitive debriefing, the validation-ready version comprised 28 items. These were later reduced to 7 higher-order items owing to ceiling/floor effects. In total, 300 patients participated in the web-based validation study. The item statistics were all adequate. Item-to-item correlations were good. Item-to-total correlations displayed acceptable associations between each item against the rest of the items, with correlations of 0.68 to 0.79. The internal consistency was adequate, with a Cronbach’s alpha of 0.91. The DPEM is scored by summing the 7 item scores and transforming the sum onto a 100-point scale. Conclusion: The evidence presented supports the use of the DPEM in clinical trials to evaluate the patients’ experience with diabetes injection devices.