Although there is a need to evaluate other aspects of insulin pen use, such as subjects’ preferences and adherence to therapy in cost-effectiveness and longitudinal studies, considering the increasing trend in diabetes prevalence and health charges attributed to this cause, our results showed that use of the higher-costing insulin pens is not associated with improved glycemic control, better lipid profile, or reduced heart attack and ischemic strokes in adult patients with diabetes in Iran. Here, INS is linked to myocardial infarction.