INS and Hypoglycemia: Patients initiating insulin therapy with pens (glargine) were more persistent (60.6% vs. 50.1%, p < 0.001), adherent (medication possession ratio, 0.73 vs. 0.57, p < 0.001) and with lower HbA1c levels in follow-up (mean adjusted change, -1.05 vs. 0.73, p < 0.001) in comparison to vial patients. In both cohorts, hypoglycemia occurred at similar rates (3.8% vs. 5.2% respectively, p = 0.21). Study drug costs were higher among pen users ($1164 vs. $762, p < 0.001).