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

Abstract

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. 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. 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. The evidence presented supports the use of the DPEM in clinical trials to evaluate the patients' experience with diabetes injection devices.