The best insulin injection pen device for caregivers: results of injection trials using five insulin injection...

Insulin injection pens have been primarily developed for self-injection among individuals with diabetes. However, an increased elderly population with diabetes has caused an increase in the number of patients who cannot self-inject insulin. Consequently, caregivers inject insulin to the patients ("other-injection"); however, insulin injection devices have not yet been developed for other-injection use.

We evaluated five devices-OptiClik (Sanofi-aventis, Paris, France), SoloStar (Sanofi-aventis), MirioPen without an antiskid tool (Eli Lilly and Co., Indianapolis, IN), MirioPen with an antiskid tool (Eli Lilly, Hyogo, Japan), and FlexPen (Novo Nordisk A/S, Bagsvaerd, Denmark). In all, 22 respondents (mean +/- SD age, 42.6 +/- 9.3 years [range, 26-57 years]), including 11 men (50.0%) and 11 women (50.0%), injected themselves (self-injection) and others (other-injection). Thereafter, respondents evaluated the ease of use and feel of the pen devices via questionnaires. As a result, we evaluated 220 procedures of insulin injections [22 (respondents) x 5 (devices) x 2 (self and other)] in this study.

FlexPen was selected as the best device for self-injection but as the worst device for other-injection. OptiClik was selected as the second worst device for self-injection but as the best device for other-injection. Moreover, for other-injection, FlexPen was too long and less stable, had poor dial visibility, was difficult to recap, and was comprehensively inferior.

We identified problems that were not apparent during studies evaluating conventional self-injection. We conclude that devices meant for other-injection should have different features from those designed for self-injection and that consideration of caregivers' viewpoints is necessary for developing an insulin device specifically meant for other-injection.