Half-unit pens offer the ability to dose insulin more precisely. Information about half-unit pen use and evidence of their benefits and drawbacks is limited. This study aims to characterize people with type 1 diabetes (T1D) who have used (current/former = EVER) vs. those who have never used half-unit pens (NEVER users) and to understand their perspective.


An observational cross-sectional online survey was administered through T1D Exchange’s online patient community,, to understand the use of half-unit insulin pens.


The 278 adult participants (156 EVER, 122 NEVER) had a mean age of 41.8 ± 12.7 years, body mass index of 26.0 ± 3.8 kg/m2, glycated hemoglobin of 6.3% ± 1.0%, and 55% were male. EVER users had T1D for a shorter duration than NEVER users (p < .001). EVER users were less likely to use continuous subcutaneous insulin infusion (p < .001) and more likely to start correcting high blood glucose at a lower level (p < .001) and low blood glucose at a higher level (p < .001). The highest ranked benefits of half-unit pen reported by its current users (N = 131) included prevention of hyperglycemia (40.5%), less anxiety or worry (23.7%), and prevention of hypoglycemia (16.8%).

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