Background: The EValuating U-500R Infusion Versus Injection in Type 2 Diabetes Mellitus (VIVID) study compared two methods of U-500R insulin delivery, continuous subcutaneous insulin infusion (CSII) and multiple daily injection (MDI), for 26 weeks in people with type 2 diabetes (T2D) requiring high doses of insulin. To assess glycemic variability (GV) and time in range (TIR), a subset of participants performed masked continuous glucose monitoring (CGM). Methods: VIVID participants were adults who had insulin requirements of >200 but ≤600 U/day and A1C 7.5% to 12%. Participants performed masked CGM for seven consecutive days on each of three occasions: before weeks 0 (baseline), 14, and 26. The primary objective was to compare GV between CSII and MDI groups, based on change from baseline of within-day standard deviation (SDw) of CGM glucose. Results: Of 54 participants enrolled, 41 with evaluable data were analyzed (17 and 24 in CSII and MDI groups, respectively). The CSII group had a significantly greater reduction from baseline in mean SDw of glucose (45.0 to 38.2 mg/dL [-8.1 mg/dL]) compared with the MDI group (47.0 to 45.8 [-0.4 mg/dL]; P = 0.047). TIR 70-180 mg/dL glucose increased significantly from baseline in the CSII group only, from 59.8% to 73.1% (change +12.9%, P < 0.05), but was not significantly different between groups. There were no significant between-group differences in the endpoint mean glucose or A1C. Conclusions: In the VIVID CGM substudy of U-500R in people with T2D requiring high doses of insulin, participants using CSII significantly reduced GV compared with MDI. CSII also significantly increased TIR with no difference between groups. [ABSTRACT FROM AUTHOR]