Relationship between Insulin Infusion Time and the Grip Strength

Abstract

Injectors for the self-injection of insulin, a drug used to treat diabetes mellitus, have been considerably improved with regard to usability and convenience as well as therapeutic safety and efficacy. However, it is possible that users may face difficulty in using them due to problems on their side, such as decreased grip strength. Therefore, there is a need to select the appropriate drug both from the formulation and injector perspective. In this study, we inves-tigated the relationship between grip strength and insulin infusion time. Grip strength of the dominant hand was measured in fourth-year pharmacy students, and the time required to infuse 8 units of insulin formulation was measured using four different pen-type injectors. The prescription quantity for each injector was determined using NDB open data. The results revealed a longer injection time for three of the four injectors (FlexTouch®: FT, FlexPen®: FP, Myriopen®: MP, and Solostar®: SS), namely FP, MP, and SS. NDB open data results also showed that FT was the most used injector despite delivering the lowest number of for-mulations. Although differences in infusion time attributed to those in grip strength were evident, we inferred that unlikely to have a direct impact on treatment efficacy, since the time difference was approximately 0.2 to 0.3 seconds for 8 units of insulin in all injectors. However, as grip strength is not the sole factor affecting infusion time, it is important to personalize instructions for individual patients.